Re: Crack at middle of arm in ARB

KD
Keith DiRienz
Wed, Jun 29, 2022 3:56 PM

Benjamin,
An ARB crossbar experiences fully reversing torsion.  If there was a
harsh service environment or if there was an initial flaw or
inclusion, a fatigue crack could grow.  A torsional fatigue crack
would grow at a 45 deg. angle.

Keith DiRienz, P.E.
FEA Technologies
Dana Point, CA

At 12:04 AM 6/28/2022, you wrote:

HI,
I saw a Anti Roll Bar of a truck getting crack at the
middle of its arm portion. It happened due to the service load for
the Anti Roll Bar. No external forces acted on the bar.
Normally the ARB will induce high stress at the corner region on
both ends ( i.e. the joining zone of horizontal and vertical lines
in the below image. It is marked by blue colour exclamatory mark).
So it is obvious that the crack may occur at this corner region.

But in this bar, the crack occurred at the middle of arm portion of
ARB, vertical line. ( It is marked by a horizontal line in red colour).

Can anyone suggest me the possible reason for the crack to happen at
this location?

Reagrds,
Benjamin Franklin F,
Ashok Leyland,
Tamilnadu,
India.

Keith DiRienz, P.E.
FEA Technologies

Benjamin, An ARB crossbar experiences fully reversing torsion. If there was a harsh service environment or if there was an initial flaw or inclusion, a fatigue crack could grow. A torsional fatigue crack would grow at a 45 deg. angle. Keith DiRienz, P.E. FEA Technologies Dana Point, CA At 12:04 AM 6/28/2022, you wrote: >HI, > I saw a Anti Roll Bar of a truck getting crack at the > middle of its arm portion. It happened due to the service load for > the Anti Roll Bar. No external forces acted on the bar. >Normally the ARB will induce high stress at the corner region on >both ends ( i.e. the joining zone of horizontal and vertical lines >in the below image. It is marked by blue colour exclamatory mark). >So it is obvious that the crack may occur at this corner region. > >But in this bar, the crack occurred at the middle of arm portion of >ARB, vertical line. ( It is marked by a horizontal line in red colour). > >Can anyone suggest me the possible reason for the crack to happen at >this location? > >Reagrds, >Benjamin Franklin F, >Ashok Leyland, >Tamilnadu, >India. Keith DiRienz, P.E. FEA Technologies