Prediction of the Elastic Properties of Z-pin Reinforced Composites Laminates under Hygrothermal Environment

The mechanical properties of Z-pin reinforced composite laminates underhygrothermal conditions were studied.A predictive model for the elastic properties of Z-pin reinforced composites was established,taking full account of the effects of temperature, humidity, and microstructure changes induced by pin insertion.Comparison with the experimental results from existing literature revealed good agreement between the calculatedresults of the model and experimental data.The study indicated that the elastic modulus of Z-pin reinforced composites decreases with increasing temperature, and the moisture-heat coupling significantly exacerbates the degradation of material properties. The transverse elastic modulus and in-plane shear modulus exhibit higher sensitivity to the hygrothermal environment, whereas the longitudinal elastic modulus is less affected.Under hygrothermal conditions, the influence mechanism of Z-pin volume contentmanifests itself as a competitive interplay between the hygrothermal softening effect of the matrix and the bridging constraint effect exerted by Z-pins.This research methodology provides an effective approach for predicting the performance of Z-pin reinforced composites in hygrothermal environments.