Damage onset analysis of optimized shape memory polymer composites during programming into curved shapes

Abstract

The unique shape memorizing ability of shape memory polymers (SMPs) and their fibre reinforced composites have offered the prospect of remedying challenging, unsolved engineering applications. Interestingly, research integrating deformable shape memory polymer composites (SMPCs) in prefabricated modular constructions, deployable outer space structures and other compactable structural components have emerged in the recent past. To ensure effective use in strength demanding applications, SMPC components must possess better mechanical properties. Increased fibre content in SMPCs will improve mechanical properties but can adversely affect the shape memory effect (SME), increasing the possibility of material damage when programming into curved shapes and bends. This will degrade the strength capacity of SMPCs in their applications. This paper details a complete study performed on this critical effect optimizing SMPC properties by means of a 3×3 Taguchi array. The study also provides an experimental framework demonstrating how these undesirable effects can be mitigated coupled with an ABAQUS finite element analysis (FEA) damage prediction strategy. Interestingly, the compression side of the specimen was found to be the most critical location prone to programming damage. In addition, a compressive stress level of 70 MPa was found to be the damage onset stress (σo) point for programming using FEA, and correlated with experimental results. The proposed experimental and FEA framework will enhance future SMPC component design, allowing researchers to predict the possibility of programming damage numerically, saving time and cost. We believe that these findings will aid researchers seeking to develop strong and efficient functional SMPCs for future engineering applications.