How to model pipe's guide support ?

Dear Sirs,

I'm trying to solve the pipe stress analysis according to the example ASME B 31.3 appendix S Fig.301.1, shown in below URL.

LINK: ASME B31.3 pipe analysis example (page 21 & 22)

I made the most of the pipe model except the pipe support at the node No.20.

No.20 support is the constraint of vertical (Y-axis) movement of the pipe, so firstly I made the SPC with dof of '13456' aroud the pipe, but the analysis result showed unexpected movement.

My SPC is fixing the vertical movement of 'node on pipe surface', but I have to made is fixing vertical movement of all pipe elements passing through at the node 20. Therefore I have to made some constraint at the node No. 20 in global coordinates, not at the node on the pipe surface.

Please refer to the attached .hm model. I assume this is non-linear analysis, but I have'nt done such analysis so I dont know what to do.

I would appreciate any advice.

Thank you in advance.

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Rahul Rajan_21763

What is the reason to go for nonlinear analysis? Can you try linear static on same by referring attached fem deck.Also I see temperature is consistent in your hm deck whereas page 281 of ASME link talks about temperature combination.

Please ensure to have the load and boundary condition should be as per the document.

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Iskw

Dear Mr. Rahul,

Thank you so much for your reply.

The problem is the vertical support at node No. 20 in ASME analysis example.

Firstly I tryied linear static analysis by simply attaching SPC with DoF of (2) in order to fix only the vertical(Y-axis) movement.

However, the result was not the same as the ASME example's result.

Please see the below screenshot.

<?xml version="1.0" encoding="UTF-8"?>

What I really have to create is vertical constraint at Node 20's grobal position, but above SPC is vertical constraint of 'local' (i.e. element's) position.

Therefore the SPC's position was moved to X-axis forward because of thermal expansion, but I want to create the vertical constraint which are not affected pipe's deformation.

The reason why I want to analyse by non-linear is that the element stress of this example depends on the structure's deformed position. following is the image of what I want to do.

image.png.dfac74da423f315d117b3792a642dc6e.png

Iskw

This is an additional question.

As for displacement, ASME's example and Hyperworks's output were almost same. (except the Y-displacement at Node 20) Therefore, I assumed my model and analysis went well, then I thought other output such as stress, axial forces, and moments were same value. (refer to below screenshot)

<?xml version="1.0" encoding="UTF-8"?>

However, other value such as axial forces and bending moments are quite different from HyperWorks's output.

Am I comparing the wrong value ?? I think axial force (each X-axis and Y-axis) can be compared by ELFORCE(each XX and YY).

In hyperworks, following SI unit were used: mm, ton, N, MPa

<?xml version="1.0" encoding="UTF-8"?>

My hm model and fem and h3d are attached fr your reference. above result can be referred in Subcase 1: Gr+Press+Mass+Thermal

Thank you.

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