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Published May 2019 | public
Journal Article

Out-of-plane mechanical characterization of acicular mullite and aluminum titanate diesel particulate filters

Abstract

This study characterizes the flexural and compressive behavior of two porous ceramic honeycombs commonly used in diesel particulate filtration, acicular mullite and aluminum titanate. Compression along the axis normal to the honeycomb cross‐section, referred to as out‐of‐plane compression, is compared to in‐plane flexure. The relationship between these loading modes is assessed using the failure strength and elastic modulus of the honeycomb structure and the constituent wall material. Weibull analyzes showed that flexure and out‐of‐plane compression exhibit similar behavior in cases where failure is governed by a single flaw, such as in acicular mullite. However, in heavily microcracked systems like aluminum titanate, compressive failure occurs by damage accumulation rather than growth of a single flaw, so compressive failure strengths are higher than flexural ones. Buckling was also shown to occur in both systems, but the geometries required are unlikely to be encountered in practical application. In the context of filter life assessment, failure in flexure occurs at much lower stresses for systems that rely on microcracking to accommodate thermal strains, so flexure is better suited as an estimate of filter strength.

Additional Information

© 2018 The American Ceramic Society. Issue Online: 02 April 2019; Version of Record online: 28 December 2018; Accepted manuscript online: 20 December 2018; Manuscript accepted: 25 November 2018; Manuscript revised: 21 November 2018; Manuscript received: 21 November 2018. The authors would like to thank The Dow Chemical Company and Dr. Aleksander Pyzik for providing acicular mullite samples and Corning Incorporated for providing the aluminum titanate samples for this study. Additionally, the authors would like to thank Dr. Matthew T. Johnson for his assistance in designing figures for this paper. This work was supported in part by the U.S. National Science Foundation Award No. DMS‐1535083 under the Designing Materials to Revolutionize and Engineer our Future (DMREF) Program. For mechanical testing, this work made use of the Central Laboratory for Materials Mechanical Properties supported by the MRSEC program of the National Science Foundation (DMR‐1121262) at the Northwestern University Materials Research Science and Engineering Center. For sample preparation and imaging, this work made use of the Optical Microscopy and Metallography Facility and the Central Laboratory for Materials Mechanical Properties at the Materials Research Center of Northwestern University, (National Science Foundation's MRSEC program, DMR‐1121262) as well as the EPIC facility of Northwestern University's NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS‐1542205); the MRSEC program (NSF DMR‐1720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. Data Availability: The raw data required to reproduce these findings are available to download from https://doi.org/10.17632/2zrh9mnfc3.1. The processed data required to reproduce these findings are available to download from https://doi.org/10.17632/2zrh9mnfc3.1.

Additional details

Created:
August 22, 2023
Modified:
October 23, 2023