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Journal of Failure Analysis and Prevention

, Volume 14, Issue 2, pp 139–147 | Cite as

Failure Analysis and Design Optimization of the Steady Rest Hanger Rod Pipe Assembly

  • Bharat Joshi
  • John George
  • Brian Rose
  • Yin Chen
Case History---Peer-Reviewed

Abstract

This article investigates the failure of the steady rest hanger rod pipe assembly weld joints of an automotive exhaust system. Rig testing of the exhaust system showed the presence of crack at the steady rest hanger rod and brace weld joints. Metallurgical investigation was performed in order to determine the root case of failure and contribution factors. Metallurgical analysis methods included visual examination, thickness measurements, optical and scanning electron microscopy, chemical analysis of the material and weld evaluation. A CAE analysis was performed to simulate the rig test. Finite element simulation of the system also showed high damage at the steady rest hanger and brace weld locations. A DOE study was conducted to identify the design variables that could impact the dynamic response of the system like the thickness of the parts, the weld characteristics of joints, etc. Design changes were proposed; to improve the fatigue life of steady rest hanger rod pipe assembly based on the results of DOE-based study. The new design was analyzed using finite element analysis and compared with the original design for fatigue life, which showed a considerable improvement in the durability of the joint.

Keywords

Automotive exhaust systems Steady rest hanger rod Failure analysis Fatigue failure Finite element analysis Design of experiments (DOE) 

References

  1. 1.
    F. De Coninck, W. Desmet, P. Sas, K.U. Leuven, E. Hansenne, Y. Van Gucht, B. Lehaen, L. Dedene, Durability assessment of lightweight stainless steel exhaust systems. ISMA, 2008_0247Google Scholar
  2. 2.
    A. Goktan, A. Yetkin, Road load data estimation on multiaxial test rigs for exhaust system vibrations, SAE Technical Paper 2002-01-0805Google Scholar
  3. 3.
    L. Meda, H. Lawrenz, M. Romzek, D. Gilmer, Structural durability evaluation of exhaust system components, SAE 2007-01-0467Google Scholar
  4. 4.
    J. George, Y. Chen, H.R. Shih, A DOE based study to evaluate the dynamic performance of an automotive exhaust system, 2013 SAE International, Paper number 2013-01-1883Google Scholar
  5. 5.
    X. Fang, M. Ciray, Y. Chen, Dynamic simulation & correlation for automotive exhaust systems, SAE 2001-01-1437Google Scholar
  6. 6.
    M.J. Mullen, A.H. Griebel, J.M. Tartaglia, Fracture Surface Analysis, Advanced Materials and Processes, ASM International, 2007, pp. 21–23Google Scholar
  7. 7.
    ASTM E 1086-08 Standard test method for optical emission vacuum spectro analysis of stainless steel by the point to plane excitation technique, 2008Google Scholar
  8. 8.
    ASTM A240/A240M-09a Standard specification for chromium and chromium-nickel stainless steel plate, sheet, and strip for pressure vessels and for general applicationsGoogle Scholar
  9. 9.
    G. Totten, Fatigue crack propagation. Adv. Mater. Processes 166(5), 39–41 (2008)Google Scholar

Copyright information

© ASM International 2013

Authors and Affiliations

  • Bharat Joshi
    • 1
  • John George
    • 2
  • Brian Rose
    • 1
  • Yin Chen
    • 2
  1. 1.Materials Engineering and Warranty Analysis LaboratoryFaurecia Emission Control TechnologiesColumbusUSA
  2. 2.Computer Aided EngineeringFaurecia Emission Control TechnologiesColumbusUSA

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