Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Import data and constraint problem

Please login with a confirmed email address before reporting spam

Hello,

I am trying to use COMSOL to do simulation on human gait. For this stage of my project, I am looking at the lower limb. I have a tibia model and also the force data (against time) collected from gait experiment. My problems here are:

1. How can I import this force data into COMSOL as the input according to time?
2. How can I apply the constraint to the tibia? Ideally, I believe applying the vertical body weight force on the top of the tibia and applying the experimental data on the distal end of the tibia. I am not familiar with COMSOL, from my experience in ANSYS, I can define the tibia to 'simply supported'. How can I do this in COMSOL?

Really need someone to shed some light to help me to finish this project and run away from my current university.

Many thanks.

1 Reply Last Post Oct 21, 2009, 10:14 a.m. EDT

Please login with a confirmed email address before reporting spam

Posted: 2 decades ago Oct 21, 2009, 10:14 a.m. EDT
Hi,

1. You can import force data against time as function. In order to do this you have to define a new function in the option menu. With the ineterpolation method, for example, you can import your data from an external .txt file. In the user guide you can found how to do this. After, you can apply this function on the boundaries that you need simply editing its name in the boundary settings menu.

2. As for the body weight force you can apply it in subdomain settings in vertical directions according to your reference system so that the body load are applied to the entire volume or surface of your model (according to your 3D or 2D geometrical model). For what concerns the constraints probably you have to apply a fixed constraint conditions to the boundaries far from the distal end of the tibia but this depends to the experiment conditions that are performed in order to obtain the force data.

Eros
Hi, 1. You can import force data against time as function. In order to do this you have to define a new function in the option menu. With the ineterpolation method, for example, you can import your data from an external .txt file. In the user guide you can found how to do this. After, you can apply this function on the boundaries that you need simply editing its name in the boundary settings menu. 2. As for the body weight force you can apply it in subdomain settings in vertical directions according to your reference system so that the body load are applied to the entire volume or surface of your model (according to your 3D or 2D geometrical model). For what concerns the constraints probably you have to apply a fixed constraint conditions to the boundaries far from the distal end of the tibia but this depends to the experiment conditions that are performed in order to obtain the force data. Eros

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.