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Failure Analysis Case Studies II
         D.R.H. Jones (Editor)
         0 2001 Elsevier Science Ltd.  A11 rights reserved                                      267








                  Failure analysis of rubber fuel pipes in aero-engines

                                                 Guoru Fu

                      Beijing Aeronuuticul  Technoiogy Research Center, Box 9203- 16, Beging 100076, China

                                   Received  19 May 1998; accepted 14 September 1998


          Abstract

            This paper describes a series of examinations and the fracture analysis of burst rubber fuel hosepipes on
          aero-engines. The bursting of the hosepipes was caused by  fatigue failure and major reasons are improper
          design of hosepipe structure, low fatigue bearing capacity and severe deformation in mounting. 8 1999
          Published by Elsevier Science Ltd. All rights reserved.

          Keywork Aircraft failures; Engine failure; Fatigue; Hosepipes




          1.  Introduction

            The bursting  of  rubber  fuel  hosepipes  on aero-engines  seriously compromises flight safety.
          Though much  research has done, the problem has not  been  solved. At least  10 incidents were
          recorded in 1994-1995  alone. The bursting happened in two types of hosepipes which we designate
          as A  and  B  respectively for convenience. This article describes  the characteristics of  bursting
          hosepipes, analyzes the failure and proposes prevention measures.




          2.  Visual inspection of hosepipes

            The characteristics of bursting hosepipes are as follows:

          (1)  There were, to some extent bending deformations in both ends of the hosepipes, with more
             deformation taking place near the end of the elbow pipe (see Fig. 1).
          (2)  For most  hosepipes  only one opening existed in the exterior of  the  rubber  at the bending
             position near the end of the metal elbow adapter, but two openings were observed in one A
             type hosepipe.
          (3)  The distance from the bursting position to the end of the adapter housing was 0-15  mm.
          (4)  The bursting shape of the outer rubber was irregular and there with axial, circumferential and
             branched cracking.
          Reprinted from Engineering Failure Analysis 6 (3), 173-180 (1999)
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