Development and Validation of Models for Durability Estimation of
Exhaust Manifolds under High Temperatures
Abstract
Air-gap insulated exhaust manifolds are mainly stressed by
thermo-mechanical loads (TMF). To calculate the components with regard
to their durability, a material model was created using a nonlinear
kinematic model of strain hardening based on
Low-Cycle-Fatique-(LCF)-tests and multi-level creep tests. On this
basis, an energy-based model for life estimation was developed. The
simulation of the LCF tests showed a good correlation. The model was
validated on the hot gas test rig using a bended pipe. Furthermore, a
model was developed to calculate welds. LCF tests with welded specimens
were carried out and based on these tests, the material model of the
basic material was modified for the welded areas.