Influence of the insertion of shape memory wires in composite materials on impact response

Abstract

In recent decades, the quest for high-performance materials—those that combine low weight with high mechanical strength—has intensified. A promising solution involves composites reinforced with fiber and a polymeric matrix. However, these composite materials often exhibit deficiencies in crashworthiness. To address this issue, we investigated the incorporation of shape memory alloys, specifically nickel–titanium (NiTi), into the laminate structure. This study aimed to develop an equation, using a design of experiments approach, capable of predicting the energy absorption capacity of fiberglass and epoxy resin matrix composites upon impact, with integrated NiTi wires. Additionally, we proposed a model through numerical simulation using the finite element method to correlate with experimental analyses, thereby establishing a reliable model for future research. We selected the appropriate NiTi alloy (martensitic or superelastic) for the impact specimens through a full factorial design and dynamic mechanical analysis. After choosing the statistically superior superelastic wire, we manufactured test specimens using vacuum assisted resin transfer molding. These specimens, designed with three variables (diameter, spacing, and position in the laminate), followed a fractional factorial design. The drop-weight impact tests, conducted according to the ASTM D7136 standard, demonstrated increased energy absorption when NiTi wire was included in the composite. A non-linear numerical simulation (dynamic analysis) was performed, and its results—showing an excellent correlation with experimental data (above 95%)—validated the model.