Compensation of residual stress induced shape errors in CFRP structures using mechanical actuators
Date of Issue2016-05-26
School of Mechanical and Aerospace Engineering
Fibercomposites, especially Carbon Fiber Reinforced PoIymer(CFRP)1 have received high recognition in numerous industries, because of their outstanding mechanical and thermal properties. However, due to curing stresses and other possible reasons, CFRP parts show distortions after manufacturing, in the form of warpage and spring-in. This results in wastage of parts especially in precision industries where high shape accuracy is required. Even after optimising the curing cycle and other parameters that Iead to curing stresses, the distortion still remain. In this thesis a postmanufacturing shape adjustment using conventional methods of mechanical actuation is suggested. Although there are state of the art actuators Iike shape memory polymers and piezo-ceramic actuators, they have many drawbacks Iike creep, Iow thermal capability etc. Mechanical actuators not only have larger actuation force capability, but also are cheap and easy to manufacture. Sample actuators made of steel were designed and manufactured fortesting the validity of the thesis and were used to produce counter deformations on the plate so that shape errors get minimized. Finite element methods were carried out to fix the position and number of actuators required and the results were validated using a test model. Experimental results of mechanical actuation on a test specimen proved reasonable shape error compensation and also showed close match with the simulation results.