Composites with epoxy matrix cannot be used in high temperature, while geopolymer matrix excel in high temperature resistance. First, prismatic specimens were subjected to conditioning temperature. Second, the tensile and bending test were performed at room temperature. This paper present comparison of mechanical properties of carbon/epoxy and carbon/geopolymer composites. Numerical simulations of tensile and bendidng tests were performed in finite element system Abaqus.

This work focuses on the numerical simulation of damage and fracture of unidirectional fiber-reinforced composite structures using the finite element method. A computational model is presented which can predict initial failure and is capable of the simulation of the subsequent process of local material damage up to final fracture. This procedure also known as progressive failure analysis originally combines Puck's failure criterion for the prediction of local failure and an innovative stiffness degradation approach for the simulation of resulting damage. The performance of the proposed model is demonstrated on examples of tensile tests of single-ply fiber-reinforced panels having different fiber orientations with and without stress concentrators. The numerical simulation is performed both as quasi-static and transient analysis and it involves identification and repetitive adjustment of material properties. The comparison of the results from experiment and from the simulation yields satisfactory agreement.

This study focuses on the comparison of selected nonlinear stress-strain relations for unidirectional continuous fiber carbon-epoxy composites and the identification of their parameters under tensile loading. Simple tensile tests of thin strips with various fiber orientations are performed. One linear relation, two types of nonlinear stress-strain relations taken from literature, and one improved relation are analyzed and used within the identification process. All the relationships are deduced from polynomial expansion of complementary energy density. The process, using a combination of the mathematical optimization method and finite element analysis, is described with the necessary details. Failure analysis for the determination of the first failure using Puck's action plane concept is also performed. The tensile and shear strengths are investigated. The comparison of the results obtained from the identified material parameters with the results obtained using the material parameters given by manufacturer is included.

No abstract

This paper deals with the progressive failure analysis of sandwich composite beam loaded with transversely low-velocity impact. A user defined material model was used for modeling of the non-linear orthotropic elastic behavior of composite skin. The non-linear behavior of foam core was modeled using Low-Density Foam material model. The numerical model was validated using performed experiment and the results in terms of deflection and contact force time dependencies are mutually compared.