Virtual testing of composites: Imposing periodic boundary conditions on general finite element meshes

Predicting the effective thermo-mechanical response of heterogeneous materials such as composites, using virtual testing techniques, requires imposing periodic boundary conditions on geometric domains. However, classic methods of imposing periodic boundary conditions require identical finite element mesh constructions on corresponding regions of geometric domains. This type of mesh construction is infeasible for heterogeneous materials with complex architecture such as textile composites where arbitrary mesh constructions are commonplace. This paper discusses interpolation technique for imposing periodic boundary conditions to arbitrary finite element mesh constructions (i.e. identical or non-identical meshes on corresponding regions of geometric domains), for predicting the effective properties of complex heterogeneous materials, using a through-thickness angle interlock textile composite as a test case. Furthermore, it espouses the implementation of the proposed periodic boundary condition enforcement technique in commercial finite element solvers. Benchmark virtual tests on identical and non-identical meshes demonstrate the high fidelity of the proposed periodic boundary condition enforcement technique, in comparison to the conventional technique of imposing periodic boundary condition and experimental data

Virtual testing of advanced composites, cellular materials and biomaterials: A review

This paper documents the emergence of virtual testing frameworks for prediction of the constitutive responses of engineering materials. A detailed study is presented, of the philosophy underpinning virtual testing schemes: highlighting the structure, challenges and opportunities posed by a virtual testing strategy compared with traditional laboratory experiments. The virtual testing process has been discussed from atomistic to macrostructural length scales of analyses. Several implementations of virtual testing frameworks for diverse categories of materials are also presented, with particular emphasis on composites, cellular materials and biomaterials (collectively described as heterogeneous systems, in this context). The robustness of virtual frameworks for prediction of the constitutive behaviour of these materials is discussed. The paper also considers the current thinking on developing virtual laboratories in relation to availability of computational resources as well as the development of multi-scale material model algorithms. In conclusion, the paper highlights the challenges facing developments of future virtual testing frameworks. This review represents a comprehensive documentation of the state of knowledge on virtual testing from microscale to macroscale length scales for heterogeneous materials across constitutive responses from elastic to damage regimes

A comparison of the gas-blast and centrifugal-accelerator erosion testers: The influence of particle dynamics

The gas-blast and centrifugal-accelerator testers are the two most commonly used erosion testers. An experimental and analytical study was made of the effect of particle characteristics (size, shape and concentration) on particle dynamics in each of these testers. Analysis showed that in the gas-blast tester both particle velocity and the dispersion angle of the particle jet were relatively sensitive to the particle characteristics. Particle characteristics, within the ranges studied, had little influence in the centrifugal accelerator tester. Consequently, during an erosion test, the range of particle velocities and dispersion angles in the gas-blast tester ismuch wider than in the centrifugal-accelerator tester. It was concluded that the centrifugal-accelerator tester gave closer control of the important erosion test parameters and therefore more consistent erosion test measurements. However, one drawback of the centrifugal-accelerator tester is the need to account for erosion effects associated with the impact of rotating particles, an inherent feature of this tester

High strain-rate properties of materials Progress report to 31st May 1985

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