Bolt Modeling in ANSYS Workbench | Compare Using circular beam connection and line body

[shiraz883]

Hi,

I have a top cover assembly wherein I have a tube (with a notch), a ring which sits in the notch, lower loose flange and top flange and bolts to connect these flanges.

I am trying to analyze the stresses in the assembly for temperature (T) and pressure load (P). Needless to mention I need to consider preload also. So I will prepare a solution combination in WB and combine P+T+Pretension and subtract T only to get primary load evaluation

I analyzed the model using 2 methods:

1. Bolts modeled using circular joint beam connection and scoping the beam to top and bottom flange cylindrical edges.
2. Bolts modeled as line bodies and connecting the ends of line body to top and bottom flanges using bonded MPC connection.

The results which I get for the temperature only load case (no preload or pressure)are different. The second option gives realistic behaviour. But I am wondering why the two do not match?

For the first option I gave the environment temp as 500°C so that the circular beam (bolt) temp is 500°C while the temp of other bodies is mapped from the temperatures obtained from steady state thermal evaluation.

For the second case the temperatures were mapped from the steady state thermal evaluation including the line bodies (bolts) so that the environment temp is not changed for the thermal analysis and it remains 22°C.

Is it possible that when I change the environment temp for the first case (to get the beam have the avg temp of bolts), the other bodies in the assembly also assume the same temperature??





Shiraz
Sr. Engineer

 

[L_K]

In environment temperature, there are no thermal strains. If you set environment
temp to for example 500C and body temperature to 100C (either mapped from earlier
analysis or thermal condition), it will shrink by temperature delta.

I am not sure if is possible to (and how if it is) to apply temperature condition
to BEAM188 element.