Caglar Oskay delivered an invited lecture at Northwestern University
Caglar Oskay delivered an invited lecture within the Structural Engineering and Infrastructure Materials Seminar Series of the Civil and Environmental Engineering Department at Northwestern University. The title of the seminar is: “A Multiscale Simulation-Based Life Prediction Approach for Heterogeneous Materials”. The abstract is as follows:
Abstract:
We will describe a multiscale simulation-based failure and life prediction approach for heterogeneous materials subjected to fatigue loads. This approach is a new alternative to the model-based life prediction approach. The multiscale methodology we employ considers multiple time scales, to account for the size disparity between loading periods and characteristic times associated with damage accumulation, as well as multiple spatial scales, to account for the size disparity between the characteristic lengths of the composite structure and the underlying constituents. The methodology is a space-time generalization of the computational homogenization method. The primary issue of computational complexity is addressed by reduced order modeling in both space and time. The multiscale approach is coupled with a probabilistic (Bayesian) parameter calibration strategy, which allows for quantification of uncertainty associated with life predictions. We will focus our discussions on the integration of the multiscale modeling and uncertainty quantification and a novel fast multiple time-scale integration strategy that significantly increases the computational efficiency of structural life prediction analysis. In the proposed time integration strategy, the elastic time stepping is employed in solving microchronological (i.e., fast time scale) problems, whereas the inelastic equilibrium is satisfied at each step of the macrochronological (i.e., slow time scale) problem. We demonstrate the efficiency and accuracy characteristics of the proposed approach and present an investigation of the damage accumulation behavior of carbon fiber reinforced polymer composites subjected to cyclic loading.