Effects of hygrothermal environmental conditions on compressive strength of CFRP stitched laminates

Abstract

Experimental and analytical investigation was conducted to understand the hygrothermal properties of uniweave T300/QY9512 laminates. Tests were performed under hygrothermal and room temperature environment separately. Effect of stitching parameters upon strength performance of laminates was predicted using FEM model. Compressive strength of laminates, under different environmental conditions, was also predicted. Test results have shown that hygrothermal environment condition has a severe effect on the compressive strength of laminates and the reduction in compression strength for stitched laminates reached up to 50%. Stitching might improve the compressive strength of laminates depending upon the environmental conditions and lay-up sequence of stitched laminates.

Anti‐symmetrical curved composite laminate subject to delamination induced by thermal cycling

“…Composite material performance depends on the interface between matrix and fiber that is constantly changing when exposed to moisture and temperature. Moisture diffusion, for instance, is activated by increasing the temperature . Therefore, the utilization of such materials in hot/wet environment can change the mechanical behavior in the matrix domain, and, consequently, may require further assessment in the realistic conditions …”

“…Moisture diffusion, for instance, is activated by increasing the temperature. [4][5][6] Therefore, the utilization of such materials in hot/wet environment can change the mechanical behavior in the matrix domain, and, consequently, may require further assessment in the realistic conditions. 4,7 The effect of thermal variation in composite laminates is considered deleterious at the interface because of differences in coefficient of thermal expansion (CTE) of fiber and matrix.…”

Evaluation of weather influence on mechanical and viscoelastic properties of polyetherimide/carbon fiber composites

“…2,14 Water absorption may lead to physical and chemical changes, which affect the viscoelastic behavior of the material. 14,15 Physical degradation consists of plasticization and swelling of the matrix. 16 The diffusion of water molecules into the polymer structure forces the macromolecules apart, so that the material expands or swells with the increase of its free volume.…”

“…2,14 Water absorption may lead to physical and chemical changes, which affect the viscoelastic behavior of the material. 14,15…”

Post-impact residual high strain rate compressive properties of carbon fiber laminates

“…9,11–13 Experimental studies have assessed the variation of compressive strength and energy absorption in laminates with respect to orientation and alignment of fibers, variation in temperature, variation in tup crosshead velocity, and presence of flaws or delamination. 6,11,14–19 Effect of in-plane or out-of-plane loading directions and the fiber weave orientation, diameter, and spacing have been characterized in these studies. Comparisons between experimental results and finite element analysis of material impact have been conducted for further inquiry into the strength and energy absorption parameters of laminates.…”