Revealing the coupled effects of hygrothermal environment and geometrical parameters on the failure of double-lap, single-bolt composite joints

Coupled effects of hygrothermal environment and geometrical parameters on the failure of a double-lap, single-bolt composite joint are investigated numerically. The studied geometrical parameters include the ratio of end distance to hole diameter (e/D) and that of width to hole diameter (w/D). Three representative environmental conditions, including −55 °C/dry (CTD), 23 °C/dry (RTD) and 70 °C/wet (ETW), are considered. Numerical progressive damage models (PDMs) that consider hygrothermal effects are established to predict the failure load and failure mode of the joints. Good agreement between the predicted and experimental results confirm the applicability of the established PDMs. The results indicate that the CTD condition increases the failure load of the joint, whereas the ETW condition decreases it. The extent of the hygrothermal effect changes with e/D, but is insusceptible to w/D. Further, the relationship between the failure load and e/D is affected by the hygrothermal condition. Under the CTD condition, the failure load reaches a plateau at a smaller critical value of e/D, compared with that under the ETW condition. However, the relationship between the failure load and w/D is unaffected by the hygrothermal condition. The failure mode depends on e/D and w/D, and is not affected by the hygrothermal condition.