Neutron Diffraction Measure Test Structure Optimization with Multi-Constraint Based on Response Surface Methodology
One of difficulties in aircraft external carriage life assessment in service is the early fatigue damage detection.To study the problem,an experimentation which includes fatigue test and neutron diffraction residual stress measure has been carried out on a test structure which is a part of an aircraft external carriage.A test structure optimization method with multi-constraint based on the RSM has been invented to solve the contradiction between the influence of stress distribution cause by the neutron diffraction measuring window and the exactitude of fatigue test life result.Firstly,two constraints and test structure stress on the fatigue dangerous position are determined.Then,the appropriate design point is chosen and simulated.The response surface model of stress on the fatigue dangerous position is fitted.An optimization process is carried out for the measuring window based on the model.Finally,the fit of response surface model and stress deviation are checked.Optimization results prove that the test structure optimized by this method can satisfy the constraint conditions of two kinds of experiment,which can give a guideline for the test structure design for future neutron diffraction and fatigue combination test.
neutron diffraction measurefatigue testresponse surface methodologystructure optimizationfinite element analysis