Piping Mass Properties - Weight for Creo 4+ (non spec driven)

[tcusumano]

Was looking for direction on best practices for piping and obtaining the weight. Creo 4.0.m130+

config.pro option piping_material_source

weight_length

or

material_dir

For weight_length there is a PTC Article - CS56730

The following formula is used to convert the Weight/Length parameter to a density:

• Density=WT_LEN/AREA
• AREA=pi /4 * [OD^2-(OD-2*WALL_THICKNESS)^2]

I am favoring the use of the material_dir but wanted feedback on practices in place in the community; pros and cons.

Thanks, Ted

[jpiotrowski]

Hi Ted,

I'd definitely recommend using the material_dir setting of the piping_material_source. The material_dir option will automatically calculate the WT_LEN if you use a different unit systems and generally MUCH easier to deal with.

The material_dir option links the material of the pipeline to the listed material in the pro_material_dir directory.

The weight_length option is a bit trickier and requires some calculations beforehand, particularly when using IPS unit system. If you're going with this option, in Creo the mass and density values are explicitly not the weight (force) - gravity needs to be accounted for in any calculations. It is VERY important to note the difference between the Creo Parametric Default unit system and IPS unit system. IPS is a measure of pound-force and Creo Parametric Default is a measure of pound-mass. You will need to convert any standard "lb/in³" densities to lbf by dividing by (32.174 ft/s2 x 12 in/ft). 

Cheers,