Shear connectors modelling

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  • Last Post 24 April 2020
Aiadema posted this 20 April 2020

Hello everyone,

I have been trying to modelate a Timber Concrete Composite (TCC) beam in Ansys Workbench, but I am not quite sure about how to model the connection between them. As you know (or don't), usually the concrete is connected to the timber using "Shear Connectors", like the ones shown in the picture below, so it exists a slip between the materials when subjected to bending.

Shear Connector

However, the main objective of the model is to obtain the stresses and deflection of the beam under sustained loads, so it is not necessary to model each connector. In this type of modelation, you can consider that each connector can be represented as a spring in the longitudinal direction, as it can be seen in the image below.

So here is mi question: How can I model the connectors as springs ? They have to act in the interface of the materials, so I should apply them there. How can I choose the nodes that the springs connect ? If it can be done like the image above, I would like to choose the stiffness of each spring and know how to draw them using Ansys workbench. I have already drawn the concrete and timber (hope ok) using a tutorial I saw on Youtube, but I have not being able to model the connectors as shown before.

Regards,
Andrés

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peteroznewman posted this 20 April 2020

 COMBIN14 is a spring element where you can define the direction the spring acts in using keyop(2).  You can define a spring rate and have a zero length spring.  The nodes on the timber side can be coincident with the nodes on the concrete side.

You will need other springs or connections between the timber and concrete beams for the other two directions and something to control rotation about the line along which all those shear nodes exist.

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  • Aiadema
Aiadema posted this 20 April 2020

Thank you Peter for the answer.

My question is more related to How to do it. My idea is to connect the centroids of each material to the interface with rigid links, and then define the spring, but I am just starting with Ansys so I have not being able to do it. In fact, I have 2 main issues:

1. How to connect a rigid link between the centroid of the material to the interface. ¿Does it affect the material behavior ?

2. With the link defined: how to define a spring in a space which does not exist (the interface between the timber and concrete is thickless).

Thanks in advance.

 

Aiadema posted this 24 April 2020

Hello Peter,

I started to make a 2D model to have a  more "user friendly"  approach to the composite beam and to the program. I used COMBIN14 elements for connecting both materials, and changed KEYOP(2) to 1, so it acts in the x direction, as you said. However, when I tried to create a 0 length spring, the program tells me I can not have 0 length springs. So I gave them a length of 25 mm (same as mesh size), but it keeps not working. Also, I still have 4 warnings that I do not know how to fix. Finally, when I check the Stresses, the concrete is not experiencing any stress, so my conclusion is that the springs are not well defined, and of course the model is not working properly.

I attached the model Im using, in case you can take a look to the file.

Thanks a lot for your help.

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