Preliminary Investigation for Optimization of Fiber Reinforced Cementitious Composite Structures

The present study addresses the preliminary steps for the optimization of fiber reinforced cementitious composites (FRC) with respect to brittle failure behavior of a single component. FRC is one of the advanced materials that consist of a concrete matrix and glass, carbon, or aramid fibers. This kind of reinforcement is corrosion free and highly durable when used in concrete, which makes it possible to produce very thin structural concrete elements. It is well known that the properties of such composites depend on the layout of the material at the microscopic level (e.g. fiber size, fiber coating, impregnation, and surface roughness among other material characteristics). The investigation of the sensitivity of the structural response of the composite material with respect to the microscopic material parameters is part of this work. To improve the structural behavior of FRC, the significant parameters of the material models for the interface and the fibers are introduced as design parameters and adjusted by a controlling optimization process. Two different objectives are investigated: strength and ductility of FRC. To perform the structural analysis, an isotropic gradient-enhanced damage model for concrete as well as fibers is used. Numerically integrated interface elements are applied for modeling the debonding between the fibers and the matrix. To obtain a reliable composite by applying structural optimization, the nonlinear failure behavior of matrix material, fiber, and interface models are considered within the optimization process [

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]. Gradient-based optimization algorithms are used to adjust these parameters to improve both strength and ductility of such composite structures [

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], [

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