Failure Analysis of Multi-Layered Thick-Walled Composite Pipes Subjected to Torsion Loading

In the current study multi-layered thick-walled fibre reinforced composite pipes under torsion loading are considered. To analyse the stress-strain distribution in the pipe the Finite Element model (ABAQUS) has been developed. Using the model the radial, hoop, axial and shear stresses have been calculated for different lay-ups of the fibre reinforced pipes, and modified Tsai-Hill failure coefficients have been computed. The validation of the model was done by comparing the results available in the literature and the semi-analytical three-dimensional elasticity solution. The dependence of the failure coefficient on winding angles and layers’ thickness was investigated and analyzed, and the appropriate design considerations have been suggested for four-layer pipes.

Alternative derivation of the higher-order constitutive model for six-parameter elastic shells

In this paper, we present a general method to derive the explicit constitutive relations for isotropic elastic 6-parameter shells made from a Cosserat material. The dimensional reduction procedure extends the methods of the classical shell theory to the case of Cosserat shells. Starting from the three-dimensional Cosserat parent model, we perform the integration over the thickness and obtain a consistent shell model of order $$ O(h^5) $$ O ( h 5 ) with respect to the shell thickness h. We derive the explicit form of the strain energy density for 6-parameter (Cosserat) shells, in which the constitutive coefficients are expressed in terms of the three-dimensional elasticity constants and depend on the initial curvature of the shell. The obtained form of the shell strain energy density is compared with other previous variants from the literature, and the advantages of our constitutive model are discussed.

Basic Solutions of Three Dimensional Elasticity

Elastic calculation method is an important research content of computational mechanics. The problems of elasticity include basic equations and boundary conditions. Therefore, the final solution consists of the general solutions of the basic equations and the special solutions satisfying the boundary conditions. Numerical method is often used in practical calculation, but the analytical solution is also an important subject for researchers. In this paper, the basic solution of three-dimensional elastic materials is given by theoretical derivation.