Scaling Effects in Glass Reinforced Epoxy Filament Wound Tubes Subjected to Quasi Static Indentation

摘要

Purpose of this work is to study scaling effects in thin walled filament wound Glass Reinforced Epoxy tubes under quasi static lateral indentation load. Input parameters including specimen geometry, spherical indenter diameter and indentation depth are scaled according to Buckingham Pi theorem. Four geometrically scaled specimens are subjected to lateral indentation load and force-displacement relation is obtained which includes initial elastic phase, damage phase with less steeper gradient and unloading phase. Force-displacement and energy-displacement behavior is found to obey the scaling law. Initial elastic region of force displacement behavior and energy dissipation data shows excellent compliance with scaling law. Consistency reduces in scaled data with damage initiation and growth in the tube wall, however scaled data shows similar trends. Damage initiation and growth is observed by placing mirror inside the tube and insitu strong back light on tube’s external surface. Damage in tube wall reflected by the mirror is recorded with a video camera. Damage growth rate is calculated by processing recorded images and video. Damage growth rate and energy scales with the same factor. Scaling factor for energy is obtained by Buckingham Pi theorem and that for damage growth is obtained by curve fitting.