Window cracks on dump truck 1

[tmusliah]

Hi,

I am a production engineer working at an earth moving equipment manufacturer, primarily dump trucks. I am primarily involved in the manufacturing of the operator cabins (cabs).

Until recently we used to manufacture the cab entirely out of steel, but our latest model uses a GRP shell over a steel frame.
The windows are bonded, much the same way other automotive companies do it. We use Sika to bond the windows to the fibre glass.

The problem we have been having recently, is the fact that the rear windows have started to crack. Initially this was put down to stone impact, but this theory was shortly dispelled.

Is there anyone out there, who might suggest a possible cause and solution for this problem.

Thanks

Trev

 

[aspearin1]

Stresses imposed on the glass due to shrinkage or warpage of the GRP? A roof load that is less supported by the GRP than the former steel? Less vibration and shock absorbance by the GRP than the previous steel?

aspearin1

 

[tmusliah]

Sorry Aspear1

I think I was a bit vague in my initial statements.

These cracks do not occur on all machines, but it seems as if there is some sort of wierd occurence that the machine goes through that causes some sort of flexing in the glass.

The glass is question is a flat sheet of laminated glass 4mmx4mm with vinyl inbetween.
The dimensions of the glass are 780mm x 1260mm, and it is only supported on its extremeties.

As a test we put some glass out in the field wth a larger cross curvature. It was originally 5-10mm, and it is now between 10-15mm. This seems to have increased the lifespan of the glass.

 

[aspearin1]

Can this be traced back to a particular lot of glass from the supplier? Can it be traced to a particular vehicle?

aspearin1

 

[tmusliah]

Hi,

I have received more info. on another forum.
Please use the link below to read further.

Thanks

Trevor

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