Advances in Structural Integrity for Mechanical, Civil, and Aerospace Applications
Proceedings of SICE 2022, Volume 1
- 2025
- Book
- Editors
- Sai Sidhardh
- S. Suriya Prakash
- Ratna Kumar Annabattula
- Phani Mylavarapu
- Book Series
- Lecture Notes in Mechanical Engineering
- Publisher
- Springer Nature Singapore
About this book
This book presents select proceedings of the 4th Structural Integrity Conference and Exhibition (SICE-2022), organized at the Indian Institute of Technology, Hyderabad. This book includes chapters written by eminent scientists and academicians broadly working in aerospace, civil, and mechanical and materials engineering within the areas of structural integrity, life prediction, and condition monitoring. These chapters are classified under the domains of aerospace, fracture mechanics, fatigue, civil structures, experimental techniques, computation mechanics, molecular dynamics and nanostructures, smart materials, energy impact, dynamics, mechanisms, structural optimization, composites, AI/ML applications, additive and advanced manufacturing, bio-engineering, structural health monitoring, nondestructive testing, and damage and failure analysis. The book can be a valuable reference for researchers, students and practicing engineers.
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Table of Contents
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Frontmatter
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Modelling Bearing Capacity of Bored Piles Under Vertical Eccentric Load Within Python Framework
Pratyusha Bandaru, Hemaraju PollayiThis chapter focuses on the modelling of bearing capacity for bored piles subjected to vertical eccentric loads within a Python framework. It introduces the concept of soil-structure interaction (SSI) and its significance in the design of superstructures. The study employs limit analysis theorems to create interaction diagrams for pile groups under vertical eccentric loads, identifying 'cap rotation' as the most common failure mechanism. The proposed formulation is based on the interaction factor method and a stepwise incremental approach, accounting for nonlinear pile behaviour. The chapter includes case studies, such as a wind farm in southern Italy, to illustrate the practical application of the suggested approach. The results demonstrate the potential for more rational and efficient design of pile foundations under eccentric loads. The chapter concludes by highlighting the importance of using ultimate moment-axial force interaction diagrams for a more accurate assessment of pile group bearing capacity.AI Generated
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AbstractThis paper deals with the modelling of load bearing capacity of bored-pile groups under the vertical eccentric load using Python. In many practical problems, the pile foundations of civil engineering structures (such as bridges, retaining walls, offshore structures) are frequently subjected to eccentric loads. There are two main tasks considered in the present work: (1) a group of equally spaced, identical piles subjected to an external moment vector, and (2) general case of a group of unevenly distributed and dissimilar piles. It is observed that the pile group subjected to vertical eccentric load failed by a cap rotation about the head of a pile and all piles within the group achieve the ultimate axial capacity in compression under the collapse mechanism. Finally, a wind turbine (with 95 m height) having a circular raft (with 16 bored piles, 22 m long, 0.8 m diameter) is modelled in the present work considering typical sub-soil profile (consisting of a deep layer of over consolidated, inorganic silty clay of high plasticity up to a depth of about 15 m with the ground water table 2.0 m from the ground level) and estimated the undrained shear strength in the intermediate layer and in the lower stiff clay. The authors will optimise the pile group under eccentric loading for the cost–benefit analysis. -
An Improved Methodology for Precise Estimation of Fracture Process Zone Size
Mansi, Tutika Kavya, Sonali BhowmikThe chapter delves into the critical role of the Fracture Process Zone (FPZ) in understanding the fracture behavior of quasi-brittle materials like concrete, rock, and ceramics. It introduces an innovative methodology to estimate the FPZ width using Digital Image Correlation (DIC) and v-displacement data, which has not been explored before. By identifying a threshold layer that separates regions of major and minor microcracking, the study provides a precise estimation of FPZ width. This methodology is particularly significant as it offers insights into toughening mechanisms within the FPZ, such as crack bridging and crack-tip blunting. The chapter also highlights the importance of FPZ size in predicting material response under various loads and bridging the gap between design life and service life of structures. The study emphasizes the need for precise observation of FPZ size and properties, which has been a debated topic among researchers. The improved methodology presented in this chapter promises to advance the understanding of fracture mechanisms in quasi-brittle materials, making it a valuable read for specialists in the field.AI Generated
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AbstractConcrete is widely used as a construction material; due to its heterogeneous behavior, the service life of the structures becomes crucial so as to avoid the sudden brittle failures. Fracture in concrete is accompanied by emergence and evolution of an inelastic zone, fracture process zone (FPZ), around the crack tip. Inside this FPZ, many mechanisms occur: crack blunting, aggregate bridging, and microcracking, which prevent brittle failure. The softening of stress–strain curve in post-peak region and the size-effect phenomena is attributed due to the existence of this FPZ. As the size of FPZ influences the toughness of concrete—larger the FPZ, higher will be toughness; it becomes necessary to quantify the length and width of FPZ. Till now, the research was primarily focused on the length of fully developed FPZ. However, for better insight into the crack growth, an accurate prediction of FPZ size is necessary. Hence, precise quantification of width is also important. In this work, an attempt has been made to estimate the width of fracture process zone using v-displacement data of digital image correlation (DIC). The study aims to propose a methodology to find the FPZ width in plain concrete members. The maximum FPZ width for monotonic loading is estimated for geometrically similar beam samples. The proposed methodology has been verified against the existing literature on other non-contact techniques, and a good agreement has been found between them. -
Investigation of the Effect of Stiffener Parameters on Post-buckling Strength of Stiffened Composite Panels Using FEA
Srilakshmi Rayasam, Siddarth Patil, Achchhe LalThis chapter delves into the critical aspects of stiffened composite panels, widely used in aerospace applications. It begins by discussing the advantages and challenges of these panels, such as high specific stiffness and strength but susceptibility to damages like stiffener debonding and interlaminar damage. The study then focuses on the significant challenge of designing composite panels with stiffeners that can withstand compression loads post-buckling. The chapter employs finite element analysis (FEA) to investigate the damage behavior of stiffened panels, validating the model against experimental data. It also introduces Rao's algorithm for optimizing stiffener dimensions, aiming to minimize the panel's weight while ensuring structural integrity. The research highlights the influence of various stiffener parameters, including shape, thickness, location, height, and distance between stiffeners, on the panel's performance. The use of Rao's algorithm, which does not require algorithm-specific parameters, is a notable innovation in this study. The chapter concludes with the identification of optimal stiffener dimensions and a comparison of different stiffener shapes, providing valuable insights for professionals in the field.AI Generated
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AbstractComposite stiffened panels are widely used in numerous components of aircraft. Stiffeners can recover stability and stiffness efficiently with less gain in the structure’s weight when compared to increasing plate thickness. In this paper, finite element analysis of stiffened panels made of composite is carried out using ABAQUS. Damage analysis within the plies is performed by implementing progressive damage modelling based on Hashin’s criteria. The initiation and evolution of the adhesive layer damage are modelled using cohesive zone modelling. A convergence study is conducted to find the optimal mesh size. Next, a parametric study is carried out by varying stiffener sections such as T, I, and C. The failure load and the post-buckling stiffness of the structure are taken as performance examiners to evaluate the concert of each stiffener. In this work, optimization of the stiffened panel is carried out by using Rao-1 Algorithm. The optimal dimensions of the stiffener height, the distance between the stiffeners, the thickness of the stiffener, the height of the stiffener, and the thickness of the panel are estimated for the given specified panel size. -
Identifying the Cracks in Beam Structures Using a Simplified Substructure Technique
Eshwar Kuncham, Md Armanul Hoda, Subhamoy SenThe chapter introduces a novel method for identifying cracks in beam structures using a simplified substructure technique. It highlights the limitations of traditional non-destructive testing methods and proposes a vibration-based approach that examines changes in the structure's vibration characteristics. The use of Bayesian filters and interacting particle ensemble Kalman filters is emphasized for their ability to improve the accuracy and efficiency of structural health monitoring. The paper presents a state-space formulation for the substructure system and demonstrates the effectiveness of the proposed method through a numerical experiment on a cantilever beam. The results show accurate and precise estimation of damage parameters and response measurements, even under noisy conditions. The method offers computational efficiency by monitoring only a specific subdomain of interest, making it a promising approach for real-world applications.AI Generated
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AbstractBeam definitions are used to simplify complex structures like bridges or skyscrapers. This study highlights the importance of monitoring beams as they are often the critical components and damage in them can result in changes in their dynamic characteristics. This study proposes a substructure-based approach for damage estimation in structural beams, that can later be extended for monitoring high-dimensional structures. The traditional approach of full structure monitoring mandates heavy instrumentation and computational costs. To avoid that, the existing subdomain estimation approaches need to deal with the quasi-static displacement at subdomain boundaries making the estimation a coupled problem. Instead, the proposed approach focuses on only monitoring a subdomain of interest, independently, making it computationally cheaper. The study employs an interacting filtering algorithm with Particle and Ensemble Kalman filters, circumventing the complexities of quasi-static displacement. The proposed approach has been tested numerically and the results are promising for further investigation and improvement. -
Analysis of the Non-circular Suture Designs on Bio-inspired Materials
C. Sachin Chandran, Pratiksha Rodewad, S. AnupThe chapter delves into the analysis of non-circular suture designs in bio-inspired materials, emphasizing the superior mechanical properties of elliptical interfaces compared to circular ones. It begins by discussing the enhanced mechanical properties of biological composites due to weak interfaces and superior architecture. The authors then introduce elliptical suture models, comparing them analytically and through finite element analysis with circular suture models. The study reveals that elliptical sutures exhibit better deformation behavior, energy absorption, and toughness, making them a promising design for bio-inspired materials. The chapter concludes by highlighting the significant role of geometry and friction in the mechanical behavior of these interfaces, providing valuable insights for future bio-inspired designs.AI Generated
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AbstractBiological composite materials found in nature like nacre, shells of cephalopods, and woodpecker beaks possess superior mechanical properties compared to their simple constituents having weak mechanical properties. The weak suture interfaces present in these biological composite materials play a significant role in achieving excellent mechanical properties since they govern the deformation and fracture mechanisms. These non-adhesive suture interfaces possess non-linear behaviour depending on friction and the geometrical interlocking. Bio-inspired sutured materials are developed by mimicking the excellent properties of biological materials. The geometry of a curved suture can be developed using the two-dimensional (2D) shape descriptor approach. In the present study, an elliptical geometry of the suture interface is proposed, and the analytical equations and finite element results are developed to capture the non-linear pullout response of the suture. -
Finite Element Analysis of Drilling Process in Carbon Fiber Composite Material: Mechanical Behavior and Delamination Prevention
Anmol Choudhary, Greegar GeorgeThe chapter delves into the finite element analysis of the drilling process in carbon fiber composite materials, specifically M21/T700 CFRP. It begins by highlighting the distinctive properties of carbon fiber-reinforced polymer (CFRP) and its applications across various industries. The study then focuses on the challenges posed by drilling in CFRP, such as delamination and other defects. Using Abaqus, the authors model the drilling process, investigating the influence of drilling forces and optimizing parameters like spindle speed and feed rate to enhance drilling efficiency. The chapter presents detailed simulations and analyses, including the variation of stress and plastic equivalent strain with different drilling parameters. The findings aim to provide practical recommendations for improving the drilling process in CFRP, making it a valuable resource for professionals seeking to optimize machining techniques in composite materials.AI Generated
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AbstractCarbon fiber-reinforced polymer (CFRP) composites have gained popularity in various fields owing to their strength, durability, and lightweight nature. CFRP is a fiber-reinforced composite material that employs carbon fiber as the primary structural component, making it suitable for aircraft components that require high strength, anisotropy, and thermal conductivity. For the components made from composite laminate, drilling is a crucial machining technique that requires particular attention. During drilling, maintaining processing quality is challenging due to the influence of drilling force, which can lead to delamination, tearing, and other defects. In this paper, we present a finite element analysis of the drilling process in carbon fiber composite and study its mechanical behavior. We developed a three-dimensional model of an M21/T700 carbon fiber-reinforced polymer and simulated the drilling process using Abaqus software. The various force components during drilling are analyzed and compared the stress and plastic equivalent strain incurred during the drilling process with the spindle speed and feed rate. This study can aid in selecting a spindle speed and feed rate combination that reduces the thrust force induced during drilling, preventing interlaminar and intralaminar failure modes at critical thrust forces. This, in turn, can assist in reducing the degradation and development of drilling tools and designing carbon fiber composite materials. -
Optimization of Orthogrid-Stiffened Cylinder Under Axial Force and External Pressure
R. Santhosh, P. C. Jain, Gangadharan RajuThe chapter delves into the critical optimization of orthogrid-stiffened cylinders, a common design in aerospace structures, to withstand axial forces and external pressure. The focus is on minimizing mass while ensuring structural integrity against buckling. Two optimization methods are explored: a low-fidelity analytical approach and a high-fidelity numerical method using finite element analysis. The analytical method provides quick estimates but may underpredict buckling loads, while the numerical method offers accurate results albeit at a higher computational cost. The study highlights the potential for significant mass reduction, with one optimized design showing a 28.13% reduction compared to a reference design. The chapter also discusses the challenges and trade-offs between these methods, making it a valuable resource for engineers seeking to enhance the performance of aerospace structures.AI Generated
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AbstractThe optimization problem of the design of orthogrid-stiffened cylinder under combined axial force and external pressure is a complex problem. It involves finding the optimal layout of stiffening rings and stringers (number of rings and stringers which are discrete variables) and sizing of members and skin (continuous variables) while minimizing the mass of the stiffened cylinder and satisfying the buckling constraints. Also, the presence of multiple modes of buckling adds to the complexity of the optimization problem. Further, the design space is nonconvex with multiple local minima, and steps must be taken to avoid sub-optimal solutions. In this paper, a methodology for carrying out systematic optimization for the stiffened cylinder is presented. The optimization problem statement is defined as the minimization of mass with buckling load factor as the constraint, and two methods are presented to evaluate the buckling load. The first method is a simplified analytical method for evaluating individual buckling modes, and the second method is a high-fidelity method where buckling load is calculated using FEM. The optimization problem is solved using both methods. A comparison is made between the optimal solutions by the two fidelity models in terms of accuracy and cost. It is observed that the low-fidelity method is suited for preliminary calculations and screening the design space. The high-fidelity method gives an optimal solution which is having significant mass savings (28.13%) compared to results in the literature. -
A Systematic Survey on Dynamic Analysis of Functionally Graded Rotor Systems
Arepalli Sri Rama Murty, Prabhakar Sathujoda, Neelanchali Asija BhallaThe chapter delves into the dynamic analysis of functionally graded rotor systems, exploring the evolution and applications of these advanced materials. It covers various fabrication techniques, including gaseous, liquidous, and solid phase methods, and discusses the modelling of thermal and mechanical properties. The text also highlights the dynamic analysis cases, comparing the performance of FGM rotors with conventional systems, and examines the effects of defects such as corrosion and cracks. Additionally, it reviews different modelling techniques, such as the power law, exponential, and sigmoid function distributions, and discusses the dynamic stiffness method. The chapter concludes with a future outlook, emphasizing the need for more experimental results and the potential of advanced analytical techniques.AI Generated
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Abstract“Functionally graded materials” (FGMs) are becoming more popular owing to merits in their thermos-mechanical behaviour and performance. However, designing the systems made of FGM, considering the practical conditions such as thermal conditions, corrosive environments, manufacturing difficulties and manufacturing defects are still evolving. Present work is aimed at reviewing different design and modelling approaches suitable specifically to rotor systems made of “functionally graded” materials. Though research is picking up in this area, limited studies have been reported on FG rotors. A step-by-step concise information has been provided on every aspect of FGM related to rotor systems, which includes brief history of FGM, literature review of fabrication methods, applications of FGM, material modelling due to gradation of materials over the cross section of rotor, temperature variant material properties because of temperature distribution, analytical and finite element methods available to analyse rotor systems subjected dynamic loads, modelling and analysis of defects such as effect of corrosion, porosity and cracks in dynamic behaviour of rotor systems. -
Mass Optimization of Bracket
Kavadi Ravi Teja, R. Santhosh, P. C. JainThe chapter delves into the critical design considerations for aerospace brackets, emphasizing strength, stiffness, material selection, and manufacturing tolerances. It introduces a methodology driven by topology optimization, sizing optimization, and finite element analysis to design a bracket housing a Reaction Control System (RCS). The study achieves a notable 49.7% reduction in mass, demonstrating the effectiveness of optimized parameters and technical ingenuity in aerospace engineering. The comprehensive approach, moving away from reliance on intuition, ensures the structural resilience and dependability of aerospace vehicles. The methodology is validated through finite element analysis and practical hardware testing, marking a significant milestone in the evolution of aerospace engineering methodologies.AI Generated
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AbstractBrackets, crucial components in aerospace structures, serve the dual purpose of load transfer and mounting packages onto airframe shells. Achieving the delicate balance between minimizing mass and meeting stringent strength and stiffness requirements is a perennial design challenge. This paper details the optimization of brackets, employing solid modeling software for intricate design and ANSYS packages for rigorous analysis and optimization. The process integrates finite element analysis to assess structural integrity, topology optimization to refine material distribution, and parametric optimization to fine-tune geometric parameters. The resulting design achieves optimal efficiency within the constraints of confined space and attachment requirements dictated by various subsystems. Beyond optimization, the design undergoes thorough manufacturability scrutiny, considering material properties and fabrication processes. The successful realization of a prototype hardware validates the proposed methodology, showcasing a seamless transition from conceptualization to a technically robust and functional bracket design. -
Stress Transfer in Two-Hierarchical Non-self-similar Bio-inspired Composites
A. J. Abhirami, S. AnupThe chapter delves into the intricate mechanical properties of bio-inspired composites, drawing inspiration from natural materials like nacre and bone. It focuses on the arrangement of constituents at the elemental level, particularly the brick-and-mortar structure, which significantly enhances toughness and strength. The study introduces two-hierarchical, non-self-similar composites and compares them with regular and stairwise staggered models using finite element analysis. The results demonstrate that hierarchical structures reduce stress concentrations and ensure a more uniform stress distribution, crucial for withstanding impact loads and improving defect tolerance. This research is pivotal for advancing the multi-scale modeling and simulation of bio-inspired composites, providing a preliminary estimation for experimental works and opening avenues for future studies on macroscopic mechanical properties.AI Generated
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AbstractThe innovations and advancements in composite materials have significantly been backed by the design of biological composites such as spider silk, nacre, bone, antler, and bamboo, owing to their magnificent mechanical properties. Even though the constituents at their basic level are weak, biological composites are characterized by superior mechanical properties like high toughness and strength which makes them unique. Bio-inspired composites, inspired by biological composites, are engineered by mimicking the essential features of the biological composites, which are responsible for their superior mechanical properties. These include geometric and material properties such as the aspect ratio of platelet, Young’s moduli ratio of platelet to the matrix, and the staggering and hierarchical arrangement of platelets. This study deals with the comparison of stress distribution in a multi-scale finite element model of a two hierarchical (2H) non-self-similar bio-inspired composite. The results of non-self similar composite which is a 2H Stairwise staggered composite with Regular staggered composite as platelets (SR) are compared with that of the models without hierarchy. -
Detection and Prediction of Bond Degradation for Piezo Impedance-Based Structural Health Monitoring (PISHM) Using Hybrid Deep Learning Model
Lukesh Parida, Sumedha Moharana, Sourav Kumar GiriThe chapter delves into the advanced application of piezo impedance-based structural health monitoring (PISHM) using deep learning models. It introduces the Sn–Ag alloy-based bonding layer as a superior alternative to traditional epoxy adhesives, showcasing its resistance to environmental stresses. The study employs deep learning techniques, including CNN, LSTM, and a hybrid CNN-LSTM model, to predict bond layer degradation conditions. Experimental results demonstrate the effectiveness of the Sn–Ag bonding layer and the superior performance of the hybrid deep learning model in accurately predicting bond degradation. The research highlights the potential of deep learning in enhancing the sensitivity and reliability of structural health monitoring systems, paving the way for more robust and efficient infrastructure maintenance.AI Generated
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AbstractIn past years, sensor-based health diagnostics have shown significant potential for electromechanical impedance (EMI) techniques with many practical implementations. In order to enhance the effectiveness of health monitoring systems, it is crucial to examine the bonding interface between the piezoelectric sensor (PZT) and the host structure. A promising approach to achieve this goal is the utilization of Sn–Ag bonding, which offers improved resistance to moisture, chemicals, and temperature compared to traditional epoxy adhesive bonding. The Sn–Ag bond layer presents a novel attachment method to the structural design, which may ultimately enhance the sensitivity of the health monitoring system. This study used EMI techniques to instrument a unique Sn–Ag alloy-based bond and compared it against an epoxy adhesive bond for better sensing and actuation. Later, both the bonds were cured, and the bond performances were analyzed through conductance and susceptance signatures. Moreover, three different bond layer damage conditions, i.e., incipient, moderate, and severe, were chosen to check the performance of the bond layer through admittance signatures. The EMI techniques rely on pristine data, which presents significant constraints when applied to pre-existing structures. Furthermore, the experimental results were used to predict baseline data through deep learning classifications, i.e., convolutional neural network (CNN), long short-term memory (LSTM), and CNN-LSTM hybrid model for all the bond layer damage conditions. The experimental results were compared against the chosen deep learning model for futuristic prediction. The efficiency of all the deep learning models is quantified using performance metrics like accuracy and R2 score. The present study demonstrates that the hybrid model yields superior performance compared to the other two models for predicting Sn–Ag and adhesive bond layer damage. The proposed framework aims to replace traditional optimization algorithms to achieve a more simplified effective prototype for the futuristic prediction of EMI signals. -
Modelling and Diagnosis of Faults in Deep Groove Ball Bearing
Naveen Kumar, Samrat Mandal, Chintamani Mishra, Nirmal Baran HuiThe chapter delves into the critical role of bearings in rotating machinery and the importance of monitoring their health to prevent machine failure. It focuses on the modelling and diagnosis of faults in deep groove ball bearings using vibration analysis. The study develops two sophisticated models: a 5-DOF MATLAB Simulink model and a multi-body dynamics CAD model using MSC ADAMS. These models are used to simulate various faults such as outer race, ball, and inner race faults, and their vibrational responses are analyzed. The results are validated against theoretical bearing characteristics frequencies, demonstrating the effectiveness of the models in fault diagnosis. The chapter highlights the practical applications of these models in simulating complex faults and testing diagnosis schemes, making it a valuable resource for professionals in the field.AI Generated
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AbstractDeep groove bearing is widely used in rotating machines as it can operate at a wide range of load and speed combinations. This article presents two simulation models for deep groove ball bearings. The first model of bearing is a 5-DOF system block diagram model developed using MATLAB Simulink environment and the second model of bearing is a detailed three-dimensional multi-body dynamic model of bearing where contact between races, slip and effects due to friction are taken into consideration and it is developed using multi-body simulation (MBS) software ADAMS. Different geometrical faults are given to the different parts of the bearing. Envelope analysis is done to the simulated signal and the result are than interpreted to find out the condition of bearing. These models of deep groove ball bearing elements can be integrated to different machine components to find the condition of industrial rotating machines. -
Numerical Study of Bulging Instability in a Porous Tube Under Internal Pressure
Bobby Dudhe, Arun Kumar Singh, Pawan Kumar Soni, Vadapalli Surya PrasanthThe chapter delves into the numerical study of bulging instability in poro-hyperelastic tubes subjected to internal pressure. It begins by introducing the concept of hyperelastic materials and their application in various industries, including the medical field where brain aneurysms are a relevant phenomenon. The study then focuses on the effects of tube length, diameter-to-thickness ratio, and void fraction on the critical pressure and stress distribution within the tube. Notably, the results show that critical pressure is independent of tube length but decreases with increasing void fraction. Additionally, the study highlights the significance of radial stress in thicker tubes and the impact of porosity on stress distribution. The chapter concludes with practical implications for designing and understanding the behavior of poro-hyperelastic tubes under pressure.AI Generated
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AbstractBulging instability is a mechanical failure that happens when a thin tube undergoes excessive localized deformation before ultimately failing. Understanding this process is crucial in ensuring the stability of various mechanical and biological systems, such as fluid-carrying rubber tubes and aneurysms in the human brains. In this numerical study, we used the finite element method and a hyperelastic material to simulate bulging instability in a closed-end tube. Our findings reveal that inflation only occurs when the internal pressure in the tube reaches a critical value, which depends on the tube's thickness but not its length. Further analysis of the poro-hyperelastic tube demonstrates that the presence of porosity lowers the critical pressure required for inflation by reducing the stresses in the tube material. -
Damage Assessment in Coated Femoral Stem Using Numerical Analysis
Samiksha Moharana, R. Gnanamoorthy, Yuichi OtsukaThe chapter delves into the critical issue of damage assessment in coated femoral stems, specifically focusing on the influence of assembly loading, coating quality, and delamination length on the interfacial region between coatings and implants. Using finite element analysis, the study examines the shear stress distribution and contact slip estimation at the coating/substrate interface in HAp/Titania-coated femoral stems. The research highlights the importance of understanding stress concentration and contact slip in predicting and preventing implant failures, providing valuable insights into the durability and performance of these materials in total hip replacements.AI Generated
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AbstractThe deterioration of bone cartilage in hip joints caused by osteoarthritis and rheumatoid arthritis is the most prevalent cause of total hip replacement. The femoral stem in the implant is fixed to the bone at the time of surgery. It is coated with biocompatible ceramics such as hydroxyapatite (HAp) to enable faster bone growth. The coating experiences relative motion during the initial period, before sufficient bone growth occurs, and loosens in many cases. Suspension plasma-sprayed hydroxyapatite (HAp)-based coatings such as HAp/Titania on titanium substrates have been proven suitable for both mechanical properties and biocompatibility. Slip occurs primarily at the coating and metallic implant interface (the bonded interface), accelerating the coating damage due to fretting. The current investigation is directed at understanding the influence of assembly load, coating property, and delamination length on the interface strength between coating and implant. A two-dimensional finite element model of a 170 mm-long femoral stem coated with HAp/Titania coating is analyzed using commercial software. The geometrical model is like the original joint condition of the human hip implant. The numerical analysis showed that the first contact edge is where the most stress and contact slip happen because that is where the stress is concentrated during an assembly loading condition. The variation in load and contact slip conditions will result in coating failure in the implant. -
Analysis of Prestressed Shape Memory Alloy Actuator for Compliant Mechanism
G. Jayabharath Reddy, S. ManiprakashThe chapter begins by introducing compliant mechanisms, highlighting their advantages over traditional actuators in terms of complexity and functionality. It then delves into the use of smart materials like shape memory alloys (SMA) as actuators, focusing on their unique thermomechanical properties. The core of the chapter is the analysis of prestressed SMA actuators, which shows that prestressing can significantly enhance the performance of compliant mechanisms. This is supported by detailed numerical simulations and practical applications, such as sun tracking mechanisms and rehabilitation robotics. The chapter also discusses the design and analysis of a simplified SMA actuator-spring system, demonstrating how prestressing can increase recoverable strain. The results show that there is an optimal prestress level for maximum strain recovery, beyond which the benefits diminish. Overall, the chapter provides valuable insights into the design and optimization of compliant mechanisms using SMA actuators, making it a must-read for specialists in the field.AI Generated
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AbstractComparing other possible actuators for compliant mechanisms, shape memory alloy has an advantage in terms of compactness and the specific actuation energy. In this work, actuation capacity of an SMA wire under different prestressed condition has been studied. To perform this study, due to the elastic nature of the compliant mechanism, the mechanism has been modeled as a spring and considered the entire system to be a spring and SMA wire assembled in series. With a suitable constitutive model for SMA, the displacement of spring has been simulated for cyclic thermal loading. This analysis has been repeated for different prestressed condition. The simulation results show the strong dependence of prestressed value with the actuator displacement. -
Free Vibration Analysis of Hybrid Fibre Metal Laminated Panels
Darshan Singh Bisht, Nikesh Chelimilla, Naresh Kali, Srikanth KorlaThe chapter delves into the free vibration analysis of hybrid fibre metal laminated panels, specifically GLARE and CARALL, under different crack lengths and boundary conditions. By employing finite element analysis, the study reveals how cracks affect the natural frequencies and mode shapes of these materials. Notably, CARALL exhibits higher natural frequencies due to its superior strength and stiffness. The research also underscores the influence of boundary conditions on the dynamic behavior of these panels, with fixed-fixed conditions yielding higher natural frequencies compared to fixed-free configurations. The detailed analysis of mode shapes and the impact of crack lengths on stiffness provides valuable insights into the structural integrity of these advanced materials, making the chapter a crucial resource for understanding the dynamic behavior of hybrid fibre metal laminated panels.AI Generated
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AbstractFibre metal laminates (FMLs) are advanced multilayered composite materials. In recent days, the demand of using these materials increased rapidly in aerospace, structural and automotive industries due to their high strength and lightweight attributes. These FMLs may be subjected to various vibratory loads and prone to damages during their working condition; in the present work, a numerical comparative study between Glass-Aluminium-reinforced Laminates (GLARE) and Carbon-Aluminium-reinforced Laminates (CARALL) with 5 mm, 10 mm, 15 mm, 20 mm length cracks and without cracks is conducted under free vibration analysis; the effect of boundary condition on natural frequency is also studied. From the results, it is clearly noticed that CARALL exhibited higher natural frequency values when compared to GLARE. It may be due to high strength and stiffness nature of the carbon fibre. It is also depicted that, as the crack length increases at the fixed position the natural frequency for different modes decreases, which may be due to decrease in stiffness of the FML. -
Finite Element Model Updating Using Modal Data
Rajpurohit Kiran, Sahil BansalThe chapter delves into the critical process of finite element model updating using modal data, essential for accurate structural system analysis and damage assessment. It explores both deterministic and probabilistic approaches, with a particular focus on Bayesian methods that quantify model uncertainties. The proposed approach leverages dynamic condensation to reduce the model's complexity and employs a modified Gibbs sampling technique to extract posterior samples. This methodology is illustrated through an example of a ten-DOF shear building, demonstrating the effectiveness of the technique in identifying structural parameters and modal frequencies with high accuracy. The chapter also highlights the challenges and solutions related to incomplete modal data and the computational efficiency of the proposed method, making it a valuable resource for professionals seeking advanced techniques in structural health monitoring and model updating.AI Generated
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AbstractFinite element (FE) model updating is a framework for identification of FE model and its parameters consistent with the system measurements. For updating FE model with uncertain model parameters, the Bayesian model updating approach is widely adopted which uses probability logic for uncertainty quantification. This approach using modal data is conducted by mode matching or without mode matching approaches. Mode matching approach requires solving the eigenvalue problem and relative weighting factors for modal frequencies and mode shapes. Whereas, without mode matching approach adopts the eigenvalue equation instead of solving it and does not require weighting factors. Due to limitations in gathering data from the structure in a single setup, model updating can be performed using data from multiple setups. Sampling techniques are commonly adopted for generating samples from posterior distribution of model parameters and its statistics. Among various sampling techniques, Gibbs sampling is appropriate for multi-dimensional problems when conditional distributions are possible for the parameters. The present work aims to perform FE model updating using modal data from multiple setups. The effectiveness and efficiency of a modified Gibbs sampling method in Bayesian model updating are illustrated by 10 degrees of freedom (DOF) numerically simulated freedom (DOF) numerically simulated example.
- Title
- Advances in Structural Integrity for Mechanical, Civil, and Aerospace Applications
- Editors
-
Sai Sidhardh
S. Suriya Prakash
Ratna Kumar Annabattula
Phani Mylavarapu
- Copyright Year
- 2025
- Publisher
- Springer Nature Singapore
- Electronic ISBN
- 978-981-9763-67-2
- Print ISBN
- 978-981-9763-66-5
- DOI
- https://doi.org/10.1007/978-981-97-6367-2
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