Method and system for improving a part's resistance to stress induced failure

A method for designing a part comprising the steps of:

• determining the total stress state of the part by adding the existing residual stress distribution of the part to the applied stress distribution of the part;
• determining the amount of residual stress which can be induced in the material from which the part is manufactured;
• modeling the total stress state acting on the material;
• superimposing the modeled stress state on a model of the part;
• identifying areas of the model which may be prone to failure as a result of localized tensile stresses;
• designing a residual stress distribution to be induced in the part such that it will cancel the effects of localized tensile stresses while minimizing distortion of the part due to the induced stress;
• utilizing a Fatigue Design Diagram in conjunction with fatigue life functions for various values of Kt to determine the magnitude of compression to be induced in the part such that it will offset the localized tensile stresses and optimize the cyclic load bearing capabilities of the part;
• determining the appropriate process and associated parameters to induce the designed residual stress distribution;
• inducing the designed residual stress distribution in the part;
• testing the part to assess the efficacy of the induced residual stress distribution;
• and
• implementing the process in the manufacturing environment.

A system for improving the resistance to stress induced failure of a part comprising:

• a computer system having software for performing a method of improving the resistance to stress induced failure of a part;
• wherein said method comprises the steps of:
• inputting into the system the existing residual stress distribution of the part;
• inputting into the system the part geometry and material properties, performing finite element analysis to calculate anticipated applied stress distribution of the part;
• calculating the total stress state of the part;
• and
• determining the residual stress distribution to be induced in the part to maximize the resistance of stress induced failure of the part.