Simulation of elastic plastic material behaviour with uncertain material parameters : a spectral stochastic finite element method approach Finite element method stochastic theory characterization of uncertainties random fields processes polynomial chaos linear stochastic finite elements polynomial chaos algebra non linear stochastic finite elements. Finite Elemente Methode Stochastik Charakterisierung von Unsicherheiten Zufallsfelder prozesse Polynom Chaos lineare stochastische Finite Elemente Methode Polynom Chaos Algebra nicht lineare stochastische Finite Elemente