Description
The mechanical behavior of brittle materials is highly dependent on flaw size and distribution, but once a crack has begun to propagate, the local microstructure plays an important role in whether that crack will lead to ultimate failure. Two case studies involving ceramic thermal barrier coatings (TBC) and polymer matrix composites (PMC) will be presented wherein the local microstructure has been shown to strongly influence crack propagation pathways as well as the active toughening mechanisms. Design of novel TBC material systems is predicated on improving the toughness of this thin ceramic coating via activation of a ferroelastic toughening mechanism. Common descriptions of ferroelastic toughening overlook the impact of local morphology including grain size, orientation, or the presence of a second phase. Preliminary efforts to deconvolute these morphological effects via strategic small-scale mechanical tests will be presented. Similar strain controlled tensile loading of PMCs will also be presented in greater context of integrating local fiber distribution into multiscale modeling efforts.
Recommended Citation
Krogstad, J. (2014). Strategic characterization of crack path propagation in brittle structural materials. In A. Bajaj, P. Zavattieri, M. Koslowski, & T. Siegmund (Eds.). Proceedings of the Society of Engineering Science 51st Annual Technical Meeting, October 1-3, 2014 , West Lafayette: Purdue University Libraries Scholarly Publishing Services, 2014. https://docs.lib.purdue.edu/ses2014/mss/mmemb/39
Strategic characterization of crack path propagation in brittle structural materials
The mechanical behavior of brittle materials is highly dependent on flaw size and distribution, but once a crack has begun to propagate, the local microstructure plays an important role in whether that crack will lead to ultimate failure. Two case studies involving ceramic thermal barrier coatings (TBC) and polymer matrix composites (PMC) will be presented wherein the local microstructure has been shown to strongly influence crack propagation pathways as well as the active toughening mechanisms. Design of novel TBC material systems is predicated on improving the toughness of this thin ceramic coating via activation of a ferroelastic toughening mechanism. Common descriptions of ferroelastic toughening overlook the impact of local morphology including grain size, orientation, or the presence of a second phase. Preliminary efforts to deconvolute these morphological effects via strategic small-scale mechanical tests will be presented. Similar strain controlled tensile loading of PMCs will also be presented in greater context of integrating local fiber distribution into multiscale modeling efforts.