Local Buckling and Collapse of FRP Structural Column

本文研究了商品薄壁箱形拉挤纤维增强塑料(FRP)结构构件的局部屈曲及其相关的倒塌行为。首先，为了揭示其基本的弹性力学行为，作者进行了各种试验：从其结构构件的板单元上切下的条形试件的拉伸试验、条形试件的弯曲试验和简支弯曲梁试验。其次，通过刺柱试验研究了钢绞线垫层对局部屈曲承载力的影响。然后观察了长柱的弹性一般屈曲行为，本研究的极限应力与欧拉屈曲准则符合得很好。在大挠度平衡状态下，其受压翼缘处会出现周期性的波浪形屈曲，并突然丧失承载能力。在相对较短的S柱中，板单元的预屈曲挠度较小，但在临界荷载作用下，板单元仍发生突然破坏。在箱形杆件中，详细的测量表明，由于弹性局部屈曲凹陷，倒塌开始于角部的横向破坏。极限应力与用正交各向异性薄壁板屈曲理论得到的局部屈曲准则一致。然而，在H型构件中，已经表明微破坏导致板单元屈曲，从而导致构件整体倒塌。

This study deals with the local buckling and the associated collapse behavior of commercially available, thin-walled box-shaped, pultruded fiber reinforced plastic (FRP) structural members. At first for revealing its fundamental elastic mechanical behavior, the author carried out various experiments ; tensile test for strip specimens cut off from the plate element of its structural member, bending test for the strip specimens and simple supported bending beam test. Second the effects of strand-mat on the local buckling load carrying capacity were investgated through stab column testing. Elastic general buckling behavior was then observed in long colums, and the ultimate stresses in this study are in good agreement with Euler's buckling criterion. At a large deflection equilibrium state, it experiences periodically wavy buckling dents at its compression flange and the sudden loss of its load carrying ability. In relatively short column s, the prebuckling deflection is small, but the plate elements still collapse suddenly at a critical load. In the box-shaped members, the detailed measurements suggested that the collapse begins in transverse failure on the corner due to elastic local buckling dent. The ultimate stresses are in agreement with the local buckling criterion obtained by using orthotropic thin-walled plate buckling theory. In the H-shaped members, however, it has been shown that the micro failure induces the plate elements to buckle and consequently the member collapses as a whole.