Thermal Effects on the Pin-Bearing Behavior of IM7/PETI5 Composite Joints

Abstract

Thermal effects on the pin-bearing behavior of an IM7/PETI5 composite laminate are studied comprehensively within this paper. Pin-bearing tests of several lay-ups at the operating temperatures of −129, 21, and 177°C are conducted to generate data on the effect of temperature changes on the pin-bearing behavior of the IM7/PETI5 material. A unique computational study investigating the factors influencing pin-bearing strength is performed for the [90,0]8s lay-up. A detailed three-dimensional finite element model is developed including the modeling of resin layers between plies in the laminate with a pin hole. Using a previously established technique, the pin-bearing problem was modeled assuming a rigid frictionless pin and restraining only radial displacements at the hole boundary. An original three-dimensional solution, where thermal residual stresses were combined with the state of stress due to pin-bearing loads was evaluated. The presence of thermal residual stresses were observed to intensify the interlaminar stresses predicted at the hole boundary in the pin-bearing problem. Furthermore, the research shows that changes in material properties drives pin-bearing strength degradation with increasing temperature. The thermal residual cure stresses then somewhat affect the extent that the pin-bearing strength changes with temperature. In general, thermal residual stresses were determined to be significant in affecting pin-bearing strength.

Effects of temperature on the response of composite bolted joints

“…The recommended one is to monitor the practical elongation of the hole diameter using an the extensometer with one probe attached to the free side of hole and another one to the bolt or loading plate. 20,29 The strain such as 0.04 is used as a criterion. Sometimes, the offset of, for example, 4% of hole diameter ( δ 0.04 ) is used to determine P max , which is the maximum load along the load-stroke curve whose offset value is less than δ 0.04 .…”

Experimental analysis of damage propagation in riveted CFRP-steel structures by thermal loads

“…Clearly, the focus of the paper is the prediction of failure load rather than the propagation and description of damages around hole edge. The correlation between interlaminar stress peaks and damaged areas under different thermal environments is investigated by [22] for pin-loaded specimens. Bearing strength is considered to be a function of thermal dependent material properties and changes in residual stresses [22].…”

“…The correlation between interlaminar stress peaks and damaged areas under different thermal environments is investigated by [22] for pin-loaded specimens. Bearing strength is considered to be a function of thermal dependent material properties and changes in residual stresses [22]. However, only a little research is discussed in the literature focusing on mixed material applications joined with rivets undergoing internal thermal loads due to different thermal elongation coefficients.…”

Investigating bearing strength of pin-loaded composite plates in different environmental conditions

“…Two stacking sequences, namely [0/45/-45/90] 3s and [90/-45/45/0] 3s , are loaded at room temperature (25 C), high temperature (150 C), and low temperature (100 C); then, the internal damages are evaluated in detail. Walker 16 studied thermal effects on the pin-bearing behaviour of an IM7/ PETI5 composite laminate. Three-dimensional finite element anlysis models are developed to fully evaluate the state of stress due to curing, in the vicinity of the bolt hole.…”