400 Commonwealth Drive, Warrendale, PA 15096-0001 U.S.A. Tel: (724) 776-4841 Fax: (724) 776-5760 SAE TECHNICAL PAPER SERIES 2000-01-1121 Finite Element Modeling of Bolt Load Retention of Die-Cast Magnesium Xuming Su Automated Analysis Corp. Keun Yong Sohn University of Michigan Don Dewhirst and John E. Allison Ford Motor Co. SAE 2000 World Congress Detroit, Michigan March 6-9, 2000Downloaded from SAE International by Brought to you by the University of Texas Libraries, Sunday, August 05, 2018The appearance of this ISSN code at the bottom of this page indicates SAE’s consent that copies of the paper may be made for personal or internal use of specific clients. This consent is given on the condition, however, that the copier pay a $7.00 per article copy fee through the Copyright Clearance Center, Inc.Operations Center, 222 Rosewood Drive, Danvers, MA 01923 for copying beyond that permitted by Sec-tions 107 or 108 of the U.S. Copyright Law. This consent does not extend to other kinds of copying such ascopying for general distribution, for advertising or promotional purposes, for creating new collective works,or for resale. SAE routinely stocks printed papers for a period of three years following date of publication. Direct your orders to SAE Customer Sales and Satisfaction Department. Quantity reprint rates can be obtained from the Customer Sales and Satisfaction Department.To request permission to reprint a technical paper or permission to use copyrighted SAE publications in other works, contact the SAE Publications Group. No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior wr itten permission of the publisher. ISSN 0148-7191 Copyright 2000 Society of Automotive Engineers, Inc. Positions and opinions advanced in this paper are those of the author(s) and not necessarily those of SAE. The author is solely responsible for the content of the paper. A process is available by which discussions will be printed with the paper if it is p ublished in SAE Transactions. For permission to publish this paper in full or in part, contact the SAE Publications Group. Persons wishing to submit papers to be considered for presentation or publication through SAE should send the manuscript or a 3 00 word abstract of a proposed manuscript to: Secretary, Engineering Meetings Board, SAE. Printed in USAAll SAE papers, standards, and selected books are abstracted and indexed in the Global Mobility DatabaseDownloaded from SAE International by Brought to you by the University of Texas Libraries, Sunday, August 05, 20181 2000-01-1121 Finite Element Modeling of Bolt Load Retention of Die-Cast Magnesium Xuming Su Automated Analysis Corp. Keun Yong Sohn University of Michigan Don Dewhirst and John E. Allison Ford Motor Co. Copyright © 2000 Society of Automotive Engineers, Inc. ABSTRACT The use of die cast magnesium for automobile transmis- sion cases offers promise for reducing weight andimproving fuel economy. However, the inferior creepresistance of magnesium alloys at high temperature is ofconcern since transmission cases are typically assem-bled and joined by pre-loaded bolts. The stress relaxationof the material could thus adversely impact the sealing ofthe joint. One means of assessing the structural integrityof magnesium transmission cases is modeling the boltedjoint, the topic of this paper. The commercial finite ele-ment code, ABAQUS, was used to simulate a well char-acterized bolt joint sample. The geometry was simulatedwith axi-symmetric elements with the exact geometry of aM10 screw. Frictional contact between the male andfemale parts is modeled by using interface elements.Material creep is described by a time hardening powerlaw whose parameters are fit to experimental creep testdata. Numerical simulation correlates well with test mea-surements for magnesium alloys AZ91D. The finite ele-ment analysis shows that the contact pressure along thelength of the screw is non-uniform.