Twist beam

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Introduction:-
Twist beam cross member was found failing in field having covered around 34392 Km and was sent for
failure investigation.
Material Observations: - Refer attached Sheets for details.

Remarks:-
1) Material and properties of cross member conforms toE46.
2) Sample has failed near the bracket welding on LH side.
3) Notch like marks as seen on earlier were observed in failed sample indicating unevenness of the plate
which may act as location of stress concentration to initiate crack.
4) Party should be asked to submit the detailed material test report indicating the mechanical properties for
TML verification.

Conclusion:-
As indicated in our earlier report (Ref. MET-106/2011/016), the major cause of the failure is that crack
initiated from uneven surface of the cross beam, resultant of improper edge condition during blanking of
sheet.