Crash resisitant plastic fuel rail 1

[riba67]

Does any body have any experience in designing a crash-resistant plastic (glass filled Nylon 66) fuel rail?

I am using Abaqus for FE modelling, but i wonder how easy is to use moldflow? How can moldflow findings be coupled with Abaqus impactr modelling?

Anybody having any material properties data specific to impact testing @ 15-20m/s (stress-strain curves).

 

[patprimmer]

The main problems you will have with your design are:-

1) Glass filled nylon is quite anisotropic in it's properties, due to the tendency of the fibres to line up parallel to each other, in line with the direction of flow. This mainly happens close to the surface.

The level of anisotrophy? is very dependant on a number of factors, being:-
direction of flow of the moulten nylon when filling the mould
the speed of fill
the fibre length to section thickness
the aspect ratio of the fibre
The shape of the fibre
The presence of non fiberous fillers

2) The properties of nylon are also very dependant on the moisture content of the part. Water molecules act as a plasticiser, and have a profound effect on both flexural modulus and elongation at break.

3) Glass content also has a significant on various properties, and the effect is not linear.


Energy to break by notched izod impact is the most commonly quoted figure fot impact strength, but it actually bears little resemblance to the mode of real world failures. A much better property to use when trying to predict breakages in nylons is the elongation at break.

I could write pages, and send reams of data, but space and time precludes this.

If you require detailed info, let me know.

Regards
pat