Predicting the failure of a component

Abstract

The invention provides a method and apparatus for predicting the failure of a component using a probabilistic model of a material's microstructural-based response to fatigue. The method predicts the component failure by a computer simulation of multiple incarnations of real material behavior, or virtual prototyping. The virtual prototyping simulates the effects of characteristics that include grain size, grain orientation, micro-applied stress and micro-yield strength that are difficult to simulate with real specimens. The invention provides an apparatus for predicting the response of a component to fatigue using the method.

1 . A method for predicting the failure of a component, the method comprising:
 obtaining a Finite Element Model (FEM) of a component;   analyzing said FEM to obtain stresses at nodes of said FEM;   identifying a subset of said nodes as significant nodes based on said stresses;   determining a Representative Volume Element (RVE) for at least one of said significant nodes;   developing an RVE microstructure-based failure model for at least one said RVE;   simulating a component life using at least one RVE microstructure-based failure model, said simulating producing a result related to said component life;   performing said simulating a plurality of times to produce results related to component life;   preparing statistics using said results; and   comparing said statistics to a probability of failure (POF) criteria to determine whether said performing predicted failure for said component.   
     
     
         2 . The method of  claim 1 , wherein said failure is due to fatigue. 
     
     
         3 . The method of  claim 1 , said simulating further comprising:
 determining an RVE life for each said RVE, said determining an RVE life comprising:   evaluating a statistically determined number of nucleation sites within said RVE utilizing probabilistic methods.   
     
     
         4 . The method of  claim 1 , wherein said RVE microstructure-based failure model comprises random variables and wherein probabilistic methods are used to provide values for said random variables. 
     
     
         5 . An apparatus for predicting the failure of a component comprising:
 a central processing unit (CPU);   an output device for displaying simulated fatigue results;   an input device for receiving input;   and a memory comprising:
 instructions for receiving input comprising a component's material characteristics, a Finite Element Model of said component; and at least one Representative Volume Element (RVE) microstructure-based failure model; 
 instructions for predicting failure of said component comprising:
 analyzing said FEM to obtain stresses at nodes of said FEM; 
 identifying a subset of said nodes as significant nodes based on said stresses; 
 determining an RVE for at lest one of said significant nodes; 
 simulating a component using at least one RVE microstructure-based failure model, said simulating producing a result related to component life; 
 performing said simulating a plurality of times to produce results related to component life; 
 preparing statistics using said results; and 
 comparing said statistics to a probability of failure (POF) criteria to determine whether said performing predicted failure for said component; and instructions for displaying a result from said predicting. 
 
   
     
     
         6 . The apparatus of  claim 5 , wherein said failure is due to fatigue. 
     
     
         7 . The apparatus of  claim 5 , wherein said simulating further comprises:
 establishing an RVE life for each said RVE; and   using each said RVE life to produce a result related to said component life.   
     
     
         8 . The apparatus of  claim 5 , wherein each said RVE microstructure-based failure model comprises at least one random variable and wherein probabilistic methods are used to provide values for said at least one random variable.