## General Mechanical

#### static and dynamic analysis

• chiheb ben abdallah
Subscriber

hello,

i'm new to ansys and i'm trynig to conduct a fatigue analysis on a semi trailer vehicle subjected to static and dynamic loads. the static load is a pressure non uniformly distributed along the upper faces of the longitudinal beams whereas the dynamic loads are the normal forces applied on the wheels due to the uneveness of the road  can anyone help me please

• Sahil Sura
Ansys Employee

Hello chiheb ben abdallah,

'Fatigue Tool' helps in getting the results regarding the life, damage, safety factor, etc.
You can also use a DesignLife Add-on to make the capacities of nCode DesignLife product in Mechanical.

You can also follow the sub-modeling approach to address the problem efficiently. (Performing Submodeling in Ansys Mechanical — Lesson 6 - ANSYS Innovation Courses)

For more information on dynamic analyses please check out (Random Vibration Analysis in Ansys Mechanical | Ansys Courses, Mode Superposition Transient Analysis | Ansys Courses)

The following references will help you to proceed with the details and steps to address the fatigue analysis. Also please find an example problem for the same.

Fatigue Tool (Group) (ansys.com)
Fatigue Results (ansys.com)
Chapter 60: Accelerated Thermomechanical Fatigue Analysis of Thermal-Barrier Coatings (ansys.com)

Hope this helps!
Thanks,
Sahil
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• chiheb ben abdallah
Subscriber

Thank you, can I ask about a method to reduce the number of elements in meshing, I'm trying to simulate the stress distribution on the chassis when the vehicle is in motion, unfortunately the number of nodes is gigantic and I don't have enough memory space for solving the model. What can I do In that regard.

Ps: I have ansys 2019 R3.

• Sahil Sura
Ansys Employee

Hi chiheb ben abdallah,
If the computational limitation is present, you can go for Linear elements (single order), as the default mesh uses second-order elements. This will help you see a change in the solution time as a relatively less number of equations will be formed for the solver to compute.
Mesh (ansys.com)
You can also go for mesh sizing options, to mesh the critical areas with relatively fine mesh.
Specifying an Appropriate Element Size for Stress Analysis — Lesson 1 - ANSYS Innovation Courses
You can also try solving the model using symmetry if the boundary conditions suit for the some cases.
Understanding when to Take Advantage of Symmetry - Lesson 3 - ANSYS Innovation Courses

Hope this helps!
Thanks,
Sahil
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• chiheb ben abdallah
Subscriber

hello, how  can i find the location of this contact mentionned in the warning, please

• Erik Kostson
Ansys Employee

See this post on how to display a specific contact element:

https://forum.ansys.com/forums/topic/how-to-display-contact-elements-id-in-ansys-workbench/

All the best

Erik

• chiheb ben abdallah
Subscriber

hello

i performed a static analysis on the semi-trailer and i want to perform a dynamic analysis using the results of the static analysis to simulate its interaction with the road  should i share the results with the model or with the setup?

i also want to determine the stresses, the displacements, and the frequencies which type(s) of dynamic analysis should i use?

• chiheb ben abdallah
Subscriber

i tried the following and i got question marks on analysis settings and submodeling. how can i fix this?

• chiheb ben abdallah
Subscriber

hello, i wnat to konw the location of the error mentioned in the results file, can you help me?

• Erik Kostson
Ansys Employee

Hi

If the model has solved and want to check where that remote point is, just create a result and scope it to that node (say node 759781 in your case).

To scope a result to a node (974 in this case) see here:

You would need to replace and add the node number of interest in the Solver Comp. Ids.

Thank you

Erik

• chiheb ben abdallah
Subscriber

Hello, no unfortunately the model is not solved and I want to know t what the message 15 joint element with lag means and the place where there is excessive penetration

• chiheb ben abdallah
Subscriber

hello,

i want to perform a dynamic analysis where  a sinusoidal force is applied on the axles of a semi-trailer. the semi trailer model is initially subjected to static loads. first i performed static anlysis then a modal analysis to extract mode shapes and natural frequencies. in modal analysis i used static structural as pre-stress.

the purpose of the simulation is to investigate the occurance of resonance when the force is applied. i tried a transient structural analysis  but i don't know whether it is the right choice or not. if not what type of dynamic analysis shoud i perform? and how can i know whether resonant vibrations occur or not?