Influence of boundary conditions on the critical and failure load in the GFPR channel cross-section columns subjected to compression

Abstract

The paper deals with experimental investigation and numerical analysis on influence of boundary conditions on critical load, post-buckling behaviour and failure load of compressed composite channel-section columns. The columns were made of 8-ply glass–epoxy laminate. The six different layers arrangement were considered.Tests were conducted using two test stands. In the first of them, special self-aligning grips with spherical bearings were used. In the second stand contains a stiff plate and a table. The stiff plate was mounted to the upper jaw and has only one degree of freedom (vertical movement). The table with spherical bearing which is mounted in the bottom jaw has 3 DOF (rotations about three perpendicular axes). The strain-gauges technique has been used for all tested specimens. Additionally the second stand has been equipped with the ARAMIS system for non-contact 3D displacement measurements.Numerical analysis was conducted using ANSYS software. Two models were prepared with boundary conditions corresponding to test stands.The critical load values were determined using following methods: the load vs. square of strain difference P−(ε1−ε2)2, the load vs. strain difference P−(ε1−ε2) curve inflection point method. To the failure load estimation the Tsai-Wu criterion and maximum stress criterion have been applied.