Project Overview

With the development of the principle of fatigue and damage tolerance in the aircraft design, there is more demand for aluminium-alloy integral structural components such as wing panels and the fuselage bulkhead, which ismachined with larger and thicker raw material (pre-stretched plate and die forging). However, increasing component size creates a greater potential for deleterious residual stresses. Due to the inherent thermal conductivity of aluminium alloys, a temperature field will be generated in the thickness direction during the quenching process. Residual stresses will be created due to the different cooling rates between the core and the surface of rawmaterial. With the increase of size and thickness of raw billets, the residual stress may increase severely.

The stress relief and rebalance of residual stress during the mechanical processing affects the dimensional stability. Residual stress affects the stress corrosion cracking and hence the service life of the structural components. Therefore, control and testing of the residual stress of the parts, especially of large size and thick section, is necessary. This project aims to create a method to remove residual stresses after quenching processes.

The mechanisms for the formation and distribution of residual stress will be identified using theoretical analysis and this will be validated using physical experiments. A special residual stress measuring method will be generated for the application. The effect of residual stress on the material strength, the fatigue life and the stress corrosion resistance will be quantified using physical experiments. An FE model will be developed to predict the residual stress generation and removal process for the patented technique. Tests will be done to prove the patented technique of removing residual stress.

Researchers

  • Dr Michael Kaye (Imperial College London)

  • Mr Ran Pan (Imperial College London)

  • Ms Chen Li (First Aircraft Institute, AVIC)

  • Ms Jinghua Zheng (Imperial College London)

  • Mr Wei Zhang (First Aircraft Institue, AVIC)