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Über dieses Buch

Experimental and Applied Mechanics, Volume 4 of the Proceedings of the 2015SEM Annual Conference& Exposition on Experimental and Applied Mechanics, the fourth volume of nine from the Conference, brings together contributions to important areas of research and engineering. The collection presents early findings and case studies on a wide range of topics, including:

Advanced Methods for Frontier Applications,

Non-Homogeneous Parameters Identification,

Teaching Experimental Mechanics in the 21st Century,

Material Characterization and Testing,

Mechanics of Interfaces

Novel Applications of Experimental Mechanics

Inhaltsverzeichnis

Frontmatter

Chapter 1. Experimental Characterization of Shape Fixity in Transversely Curved Unimorph Shape Memory Polymer Actuators

Abstract
Shape memory polymers (SMP) have the potential to be utilized as a lightweight, solid state actuator in modern reconfigurable structures including as deployment systems for satellite solar panels or morphing aircraft wings. This study is predominantly focused on the use of Veriflex-S®, a thermally activated shape memory polymer, and bi-directional carbon-fiber-reinforced polymer (CFRP) in a unimorph actuator configuration. One of the deficiencies of shape memory polymer structures is the lack of recovery after a single or multiple thermo-mechanical cycle(s). The novel concept of incorporating transverse curvature in the CFRP substrate, similar to that of an extendable tape measurer, has demonstrated the ability to improve shape recovery by increasing the bending stiffness of the unimorph composite actuator to compensate for the lack of recovery of the SMP. Another deficiency of SMP actuators is the lack of retention of the stored or deformed shape over time. This paper is concerned with the effect of transverse curvature on the shape fixity when the unimorph composite is mechanically deformed into a stored configuration. A set of experiments was designed to determine the influence of transverse curvature, the relative widths of SMP and CFRP substrate, and SMP thickness on actuator fixity after a thermo-mechanical cycle. The performance of SMP unimorph actuators with varying levels of transverse curvature in the substrate were evaluated versus SMP unimorph actuators with a flat substrate. The ability of the unimorph actuator to minimize shape retention loss was evaluated by determining the deflection angle over time after being released from the stored configuration. Experimental results indicate that in most circumstances transverse curvature does not negatively affect the ability of the unimorph actuator to retain its shape fixity. Cases of 100 % or greater retention of shape fixity were documented which could lead to the expanded use of transversely curved shape memory polymer unimorph actuators in reconfigurable structures.
Jason T. Cantrell, Jordan R. Van Hall, Andie J. Young, Peter G. Ifju

Chapter 2. Full-Field Three-Dimensional Characterization of Non-repetitive Motions by Single-Shot Multiplexed Digital Holography

Abstract
Typically, in 3D displacement measurements, the sample is repeatedly loaded at least three times and the displacement fields are obtained from multiple sensitivity vectors. However, for studying transient and non-repetitive phenomena, including, but not limited to, displacement fields of temporally-varying biological tissues, repeating the experiment is not an option. Therefore, to measure 3D displacements in such applications, all the measurements have to be done concomitantly. In this paper, single-frame, multiplexed holography is used for simultaneous quantification of 3D displacement fields. In our approach, the hologram of an object of interest is recorded in an off-axis configuration, with three simultaneous incoherently-superimposed pairs of reference and object beams. Three different spatial carrier frequencies are realized by small differences in the angle of illumination of each reference wave with respect to the CCD sensor. Therefore, the reconstructed image corresponding to each illumination direction is reconstructed at a particular position on the image plane. Because of the differences in the position of each reference beam and wavelength of each pair of beams, the reconstruction distance and magnification of each sensitivity vector are different. Therefore, we developed and implemented registration algorithms to accurately translate individual views into a single global coordinate system. Representative results highlighting the 3D measuring capabilities of our holographic system are presented.
Morteza Khaleghi, Jérémie Guignard, Cosme Furlong, John J. Rosowski

Chapter 3. Basic Foundations of Signal Analysis Models Applied to Retrieval of Displacements and Their Derivatives Encoded in Fringe Patterns

Abstract
All the techniques that measure displacements, whether in the range of visible optics or any other form of field methods require the presence of a carrier signal. The carrier signal is a wave form that is modulated (modified) by an input, deformation of the medium. The carrier is tagged to the medium under analysis and deforms with the medium. The wave form must be known both in the unmodulated and the modulated conditions. There are two basic mathematical models that can be utilized to decode the information contained in the carrier, phase modulation or frequency modulation, both are closely connected. Basic problems that are connected to the detection and recovery of displacement information that are common to all optical techniques will be analyzed. This paper is concentrated in the general theory common to all the methods independently of the type of signal utilized. The aspects discussed are those that have practical impact in the process of data gathering and data processing.
Cesar Sciammarella, L. Lamberti

Chapter 4. Recent Optical Measurements for the Mechanical Properties of Thin Films

Abstract
With advances in the technology behind micro-systems, the mechanical properties of sub-micron and nano-scale thin films have become an item of particular interest. We demonstrate two recent development of using optical methods to measure the mechanical properties of thin films. First, a paddle-like cantilever beam test structure with nano-scale metal films deposited on its top was successfully fabricated and calibrated using standard CMOS processes. Paddle cantilever beam deflection was obtained using a four-step phase-shifting process with a Michelson interferometer. Film strain was determined using a simple force equilibrium equation. Residual stresses were measured and observed at different thicknesses. High tensile stress forms during the early deposition stage for thin film due to grain coalescence, and a decrease in stress with an increase in film thickness. With thicknesses greater than 150 nm of Cu film, lattice relaxation associated with the surface mobility of metallic atoms changes residual stress from tension to compression. Second, it summaries the XRD measurements of the bulge tested thin film. We annealed thin films and tracked the texture transformation using X-ray diffraction while independently varying the stress in the film using a bulge test apparatus. The bulge height was measured as a function of pressure using a optical interferometer, using the bulge as the fully reflective surface, and an optically flat half-silvered mirror as a reference surface. A CCD camera was used to record interference fringe motion as the pressure was increased. Results show that applied stresses have no links on the kinetics of the texture transformation in films.
Chi-Jia Tong, Y.-T. Wang, Y.-C. Cheng, M.-T. Lin

Chapter 5. Evaluation of the Penalized Least Squares Method for Strain Computation

Abstract
This work proposes an alternative procedure to smooth and differentiate experimental full-field displacement measurements to get strain fields. This one, the penalized least squares method, relies on the balance between the fidelity to original raw data and the smoothness of the reconstructed ones. To characterize its performance, a comparative study between this algorithm and two other commonly implemented strategies (the ‘diffuse approximation’ and the Savitzky-Golay filter) is achieved. The results obtained by the penalized least squares method are comparable in terms of quality of the reconstruction to those produced by the two other algorithms, while the proposed technique is the fastest as its computation time is totally independent from the asked amount of smoothing. Moreover, unlike both other considered methods, it is possible with this technique to perform the derivation to obtain strain maps before smoothing them (while the smoothing is normally applied to displacement maps before the differentiation) which can lead in some cases to a more effective reconstruction of the strain fields.
Raphaël Moulart, René Rotinat

Chapter 6. Speckle Projection Profilometry Using a Diffractive Telecentric Arrangement

Abstract
A modified approach to 3-D shape measurement using the Speckle Projection technique is proposed and demonstrated. Images of a random speckle pattern are obliquely projected onto a reference plane and then onto the specimen surface. The apparent local in-plane image displacements determined by two-dimensional Digital Image Correlation (2-D DIC) combined with triangulation to provide the surface height or shape of the specimen. Here, the projected pattern is created using a custom telecentric projector. This enables the physical projection to follow closely the theoretical assumptions typically used in triangulation and to avoid the artifacts introduced when using the expanding projection created by a typical projector arrangement. In addition, the apparent size of the telecentric projected image remains constant within a significant range of out-of-plane displacements or non-zero surface heights. This feature aligns the apparent in-plane image displacement due to specimen shape to a single direction. Therefore, measurements of any displacements in the second in-plane direction provide an independent measure of changes in camera perspective, effectively reducing the need for pre-measurement calibration. Finally, the use of a diffraction grating creates a parallelogram projection, equalizing the optical path lengths of the entire projected pattern. This maximizes the range of telecentricity or nearly parallel focus of the projected speckle, allowing objects with large surface height variation to be measured accurately. An example optical system is presented and the practical features are explained. Experimental results for a cylinder specimen and also a complex shaped specimen show that the method is effective and accurate. This approach allows for shape measurements to be made efficiently, with minimal calibration and reduced mathematical complexity.
Wade Gubbels, Gary S. Schajer

Chapter 7. Use of VFM for Heterogeneity Evaluation of Materials Under Uniaxial Tensile Stress

Abstract
Identification of spatially varying stiffness is a challenging, but important, research topic especially as materials become more complex and are used in extreme environments. Examination of heterogeneity is often accomplished by unique test fixtures capable of creating the necessary stress configurations for heterogeneous stiffness identification. In this work the Virtual Fields Method (VFM) was used to identify stiffnesses in a simple geometry, namely uniaxial tension, of a simulated material with an inclusion whose stiffness gradually increases from that of surrounding material. Three different VFM analyses were examined and their results compared. Results suggest that cooperative use of these analyses could provide reasonable stiffness identification for heterogeneous materials using uniaxial tensile tests.
John Considine, F. Pierron, K. T. Turner

Chapter 8. Optimized Test Design for Identification of the Variation of Elastic Stiffness Properties of Loblolly Pine (Pinus taeda) Pith to Bark

Abstract
This article presents the design optimization of an un-notched Iosipescu test specimen whose goal is the characterization of the material elastic stiffnesses of a Loblolly (Pinus taeda) or Lodgepole pine (Pinus contorta) sample in one single test. A series of finite element (FE) and grid simulations were conducted to determine displacement and strain fields for various ring angles, ring spaces, and proportions of latewood per ring. These displacement and strain fields were utilized to determine the constitutive parameters for the woody material using VFM. Using an error function based on a comparison of the input stiffnesses and those identified by grid simulation information it was possible to narrow the optimum ring angle at which test specimens should be tested. The results of this work suggest that the starting angles for the un-notched Iosipescu test specimens should be approximately 45° to produce the smallest identification error.
D. E. Kretschmann, J. M. Considine, F. Pierron

Chapter 9. Investigation of the Hydric Transfer Phenomenon in Wood at the Ring Scale with the Grid Method

Abstract
The water diffusion phenomenon and its effect on the deformation of wood samples are studied here. A suitable experimental device is designed to impose a direct contact on one side of the specimen with water. Strain maps are measured over time on the other side. The grid method is used for this purpose. White fir of Massif Central (Abies alba Mill) is studied here. During the experiments, strain gradients clearly appear between early and late woods, highlighting the different diffusion properties at the scale of the rings. The results also show changes in the moisture diffusivity of the material during the test. A cycle of adsorption/desorption is also studied. Results highlight the existence of residual strains at the wood ring scale.
Djily Dang, Evelyne Toussaint, Michel Grédiac, Rostand Moutou Pitti

Chapter 10. Extension of the Non-linear Virtual Fields Method to Inertial Heterogeneous High Strain Rate Tests

Abstract
This paper presents the development of a novel inertial test for the identification of non-linear parameters for elasto-plastic constitutive models at high strain rates. After briefly presenting the principle of the approach (stress reconstruction from acceleration fields measured using an ultra-high speed camera), the methodology is detailed including the development of the identification routine and the experimental implementation. Results will be discussed and future work presented.
S. Dreuilhe, F. Pierron

Chapter 11. Experimental Mechanics for Graduate Students

Abstract
This talk provides a description of a current graduate course in experimental mechanics taught at Brown University. This course is designed for graduate students with a strong engineering background who want to learn more about the physical and mathematical principles behind experimentation. It includes the fundamentals of optics, optical interferometry, and imaging systems including Digital Volume Correlation and Particle Image Velocimetry. It will also include signal processing, and spatial and temporal filtering techniques. The goal of the course is to give students a quantitative appreciation of commonly used experimental methods in mechanics, their applications, limitations and theories. Students will be able to apply the theories learned in lectures to carefully designed laboratory experiments. As such the course is intended for all students with interests in continuum mechanics. The purpose of this talk is to give the audience an overview of how experimental mechanics can be integrated into the pedagogy of the classroom.
Christian Franck

Chapter 12. Bridge Foundation Depth Estimation Using Sonic Echo Test

Abstract
Nondestructive Tests are capable of determining unknown characteristics of the bridge foundations especially the depth of the piles and drilled shafts. Sonic Echo—Impulse Response (SE/IR) is one of the methods used in determining the depth of wooden and concrete piles and drilled shafts. When the top of the pile is inaccessible, sonic waves in the pile would be generated by either horizontally striking the side of the pile or striking vertically on a block attached to the pile surface. In the present research, in order to have reasonable criteria to determine the depth of piles, the data acquired by the sensors should be interpreted properly. In addition, while a sensor is mounted somewhere far from the top of the pile, the sensor receives different echoes at different times and reflection of the waves from the top of the piles and superstructures makes the case more complicated. In order to develop a methodology for testing and Interpretation, tests were conducted and analyzed in the laboratory and on railway bridges in New Mexico.
Saman Rashidyan, Tang-tat Ng, Arup Maji

Chapter 13. Detonation of Small Charges Buried in Cohesionless Soil

Abstract
As a preliminary to an experimental program involving larger charges, the detonation of 100 g of the explosive C4 has been analyzed by varying several soil and geometry parameters.
The particle size distribution, mass density and water content of the tested soils have been controlled before and after the shots. Particular emphasis was laid on the influence of the water saturation, and tests were performed on dry and saturated soils. Mass density and water content were measured both by densitometry and by standard laboratory test methods.
The preparation of the soil in the tank, including the protocols of filling the tank with the soil, wetting and compacting steps, has been standardized to improve repeatability. Three depths of burial have been considered. The propagation of the shock wave is visualized via shadowgraphy, which also provides indications on the cone of ejection of the soil particles and ejecta, despite the sand dust.
The speed of propagation of the pressure wave and its time course are recorded through five gauges located on a shaft at the vertical of the charge. The vertical force induced by the explosion is also recorded by a transducer placed at the bottom of the tank. The craters left by the explosion are measured by a 3D scanner.
Eve Roger, Benjamin Loret, Jean Paul Calvel

Chapter 14. Similitude Analysis of Composite I-Beams with Application to Subcomponent Testing of Wind Turbine Blades

Abstract
The mechanical behavior of new materials for wind turbine blades is initially characterized by using coupon testing. If the results of the coupon testing look promising, then the materials are incorporated into a blade and certified through a full-scale blade test. The coupon testing is not always representative of performance of the new materials, and full-scale-blade testing is time consuming and very expensive—on the order of several hundred thousand dollars. To bridge the large gap between coupon testing and a full-scale test, subcomponent testing is proposed as a cost-effective alternative. To design a meaningful scaled-down subcomponent emulating the structural conditions experienced in the full-scale component, it is proposed that similitude theory can be applied to a scaled replica of the I-beam structure of a wind turbine blade involving spar caps and the shear web. In the current research, the governing equations for the bending of a simply-supported shear deformable thin-walled composite I-beam are analyzed to derive the scaling laws. Fidelity of the derived scaling laws is then examined as a model-validation criterion by mapping the maximum deflection of variant subcomponents to the full-scale composite I-beam. The combined effects of the size of the subcomponents and the ply stack-up schemes on the fidelity of the scaling laws are then investigated through complete and partial similarity conditions. According to the results, preserving the aspect ratio plays a critical role in successful prediction of the maximum bending of the full-scale I-beam. Also, subcomponents with a modified ply stack-up could be found with good accuracy in maximum bending prediction using the derived scaling laws.
Mohamad Eydani Asl, Christopher Niezrecki, James Sherwood, Peter Avitabile

Chapter 15. Validating FSI Simulations in LS-DYNA 971 R7

Abstract
The latest version of LS-DYNA includes multi-physics capabilities that allow the computational fluid dynamics and structural solvers to be combined. This presents a powerful tool for automotive engineers that can be used in designing body panels. Body panels are one of the easiest locations to eliminate weight from, however, if panels are made too thin they become susceptible to a phenomenon known as oil-canning. Oil-canning can occur under loading conditions such as those found in automotive air dryers. Oil-canning is a complex phenomenon that can result in either temporary or permanent deformation of a panel. Fluid–structure interaction simulations provide a possible design tool for predicting oil canning events, however the numerical results must be validated. An experimental program is presented where automotive roof panels are placed into a custom test rig and loaded with a high velocity air jet. Flow characterization is performed by building a pressure map for various conditions with piezo-resistive pressure transducers. The flow data is used in an LS-DYNA simulation of the experiment and the results are compared to determine the validity of the numerical simulation as a design tool.
Kevin A. Gardner, Jeremy D. Seidt, Amos Gilat

Chapter 16. In Vitro Experimental Study for the Determination of Cellular Characteristics of Mesenchymal Stem Cells Using a Non-uniform Deformation Field

Abstract
In the present study, relationship between cell orientation angle and strain value of membrane was comprehensively investigated using inhomogeneous strain field. And an axial strain threshold of cell, which corresponds to launch of cell orientation migration, was elucidated. One of the advantages in this study was that the inhomogeneous strain distribution was easily created by making a little improvement in a commonly-used uniaxial stretching device. The strains of two-dimensional stretched membrane were quantified position by position using digital image correlation (DIC) method. A 3D histogram of the cell frequency, which correlated with the cell orientation angle and normal strain of the membrane, made it possible to determine the axial strain threshold accurately. The value was 4.4 ± 0.3 %, which was reasonable compared with past study conducted by other researcher, although the past experiments were based on cyclic uniaxial stretch stimulation (homogeneous strain field). In addition, a preferential axial strain of the cell was achieved using the same technique of the determination of the axial strain threshold. This work has novel values at three points: (i) Determining axial strain threshold of the cells precisely. (ii) First suggestion of preferential axial strain of the cells. (iii) Investigating methodically cell behavior in inhomogeneous strain field.
Yasuyuki Morita, Toshihiro Sato, Sachi Watanabe, Yang Ju

Chapter 17. Development of New Method for Direct Measurement of High Strain Rate Testing Parameters

Abstract
High strain rate testing and dynamic characterization of materials have been always serious challenges. Traditional Split Hopkinson Pressure Bar (SHPB) is being used for this purpose for the last 100 years. Traditional SHPB concept relays completely on the one dimensional stress wave propagation theory that adopts several assumptions. Besides, this method is subjected to some limitations of specimen dimensions, specimen material type, bars material, pulse shaping and others. The new developed direct measurement SHPB utilizes two force sensors to measure forces on both sides of the tested specimen thereby the stress on the specimen. Also, it utilizes two laser displacement sensors to measure the displacement on both sides of the specimen thereby measure the strain and the strain rate. This system measures the stress, the strain and the strain rate simultaneously all through the test period. The new developed method opens the door for great developments in the field of dynamic testing and characterization of all types of materials. It is a non-assumptions method independent of specimen material or dimensions.
Rafid M. Kully

Chapter 18. Simultaneous Measurement of Polymerization Stress Evolution, Conversion Kinetics, and Exotherm in Real-Time

Abstract
Photopolymerized composites are used in a broad range of applications with their performance largely directed by reaction kinetics and contraction accompanying polymerization. Herein, we demonstrate an instrument capable of simultaneously collecting multiple kinetics parameters for a wide range of photopolymerizable systems: degree of conversion (DC), reaction exotherm, and polymerization stress (PS). Our system consists of a cantilever beam-based instrument (tensometer) that has been optimized to capture a large range of stresses. The sample configuration allows the tensometer being coupled to a fast near infrared (NIR) spectrometer collecting spectra in transmission. Using our instrument design, simultaneous measurements of PS, DC, and exotherm are performed, for the first time, on a commercial composite with ~80 % (by mass) silica particle fillers. This new system is expected to provide new insights into kinetics and property relationships for photopolymerized composites.
Zhengzhi Wang, Forrest A. Landis, Anthony A. M. Giuseppetti, Sheng Lin-Gibson, Martin Y. M. Chiang

Chapter 19. Symmetric and Asymmetric Double Cantilever Beam Methods for Interfacial Adhesion Strength Measurement in Electronic Packaging

Abstract
This paper discusses Double Cantilever Beam (DCB) test methods that were developed for characterizing adhesion strength of several critical interfaces in advanced microelectronic packaging. Those interfaces include silicon-epoxy underfill and solder resist-epoxy underfill. A unique sample preparation technique was developed for DCB testing of each interface in order to avoid the testing challenges specific to that interface—for example, silicon cracking and voiding in silicon-underfill samples and cracking of solder resist films in solder resist-underfill samples. Additionally, asymmetric DCB samples (i.e., different cantilever beam thickness on top compared to the bottom) were found to be more effective in maintaining the crack at the interface of interest and in reducing the occurrence of cohesive cracking when compared to symmetric DCB samples. Several case studies using DCB for material selection and assembly process optimization are also discussed. Furthermore, fractography results from SEM examination of the fractured surfaces are also presented for better understanding of the failure mode.
Tsgereda Alazar, Santosh Sankarasubramanian, Sivakumar Yagnamurthy, Kyle Yazzie, Pilin Liu, Pramod Malatkar

Chapter 20. Experimental Study of Mechanical Performance in Friction Stir Welded Dissimilar Titanium Alloys

Abstract
Friction Stir Welding (FSW) is a solid state joining process widely used in aerospace industry for near net shape manufacturing. In the past, FSW has been well established with similar titanium alloys. The process is mainly optimized for titanium alloy, Ti-6Al-4V, to produce defect free joints of it. The current study evaluates FSW with dissimilar titanium alloys that include, Ti-6Al-4V, Ti-6242, and Ti-54MFG to broaden the application of the process with titanium alloys. FSW of dissimilar titanium joints was studied by varying its process conditions, namely, rotation speed and feed rate during the process. The experimental study of effect of process parameters on friction stir welded dissimilar titanium joints was conducted to investigate the mechanical performance of joints. The mechanical performance of joints showed that the modulus of elasticity close to 120 GPa and average ultimate strength of 920 MPa was obtained. The optimum values of rotation speed and feed rate were identified for joining dissimilar titanium alloys.
Neha Kulkarni, M. Ramulu

Chapter 21. Testing a Multi-bay Box Subjected to Combined Loads

Abstract
The COmbined Loads Test System (COLTS) facility at NASA Langley Research Center provides a test capability to help develop validated structures technologies. The test machine was design to accommodate a range of fuselage structures and wing sections and subject them to both quasistatic and cyclic loading conditions. The COLTS facility is capable of testing fuselage barrels up to 4.6 m in diameter and 13.7 m long with combined mechanical, internal pressure, and thermal loads. The COLTS facility is currently being prepared to conduct a combined mechanical and pressure loading for a multi-bay pressure box to experimentally verify the structural performance of a composite structure which is 9.1 m long and representative of a section of a hybrid wing body fuselage section in support of the Environmentally Responsible Aviation Project at NASA. This paper describes development of the multi-bay pressure box test using the COLTS facility. The multi-bay test article will be subjected to mechanical loads and internal pressure loads up to design ultimate load. Mechanical and pressure loads will be applied independently in some tests and simultaneously in others.
Marshall Rouse, Dawn Jegley

Chapter 22. A Study on the Generation of a Fine-Grained Layer in Upsetting Between Flat and Conical Dies

Abstract
A narrow fine-grained layer is generated in the vicinity of frictional interfaces in many manufacturing processes. The majority of previous studies on this topic is devoted to machining. The present is paper concerned with the generation of a fine-grained layer in upsetting of hollow cylinders between flat and conical dies. The layer occurs in the vicinity of the friction surface between the specimen and the conical die. The die angle varies to change the state of stress and strain near the friction surface. No lubricant is used to increase the friction stress. Based on a proposed criterion that defines the fine-grained layer, it is demonstrated that its thickness depends on the die angle. Moreover, the thickness varies along the friction surface. A general continuum mechanics model is proposed to connect the thickness of the fine-grained layer and the strain rate intensity factor. The model is based on dimensional analysis and a number of general assumptions. The strain rate intensity factor in the upsetting process is determined by an approximate method. Then, the experimental results are used to find some input parameters of the theoretical model.
Robert Goldstein, Sergei Alexandrov, Dragisa Vilotic, Leposava Sidjanin

Chapter 23. Interface Microstructure and Strength of TLP Bonded Iron and Steel

Abstract
Commercially pure iron (Fe) and stainless steel 321 (SS 321) were transient liquid phase (TLP) diffusion bonded using Cu and/or Au-12Ge interlayers. The joining pressures, temperatures and times were investigated. Au atoms appeared to diffuse back at the joining interface during slow cooling from the joining temperature. A faster cooling method prevented the back-diffusion of Au atoms from interior to the joining interface. Residual interlayer disappeared when faster cooling methods such as air cooling, water cooling or water quenching were applied. However, microcracks appeared in the joint centerline if water cooling or quenching was applied. Au-rich particles also appeared in the joint microstructure. No microcracks appeared for the samples cooled in air from the bonding temperature. The highest strength of the TLP diffusion bonded Fe reached almost same as the normalized Fe. The maximum tensile strengths (UTS) obtained for the bonded Fe were 291 ± 2 MPa using a Cu interlayer and 315 ± 4 MPa. The maximum strength found was 387 ± 4 MPa for TLP diffusion bonded steel using an Au-12Ge interlayer. The maximum strength for steel was obtained for the samples bonded at 1050 °C for 20 h in vacuum and cooled in air. The maximum strength found was 387 ± 4 MPa which is 70.4 % of the base alloy strength.
A. H. M. E. Rahman, M. N. Cavalli

Erratum: Experimental and Applied Mechanics, Volume 4

Proceedings of the 2015 Annual Conference on Experimental and Applied Mechanics
Without Abstract
Cesar Sciammarella, John Considine, Paul Gloeckner
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