## General Mechanical

#### Question – Simulation of Ultimate Load Capacity of Steel Tubular Infilled With Concrete

Subscriber

Dear all,

I tried to re-create FE model of steel tubular infilled with concrete just like my reference journal (in attached file). My reference journal use ABAQUS to modeling the steel tubular infilled with concrete. I have follow the instruction from this link to make my own model using ANSYS. But there are some problem that I don't understand such as microplane method for concrete (link2) as the recommendation from 1st link and the element that I should use.

So my main problem is the ultimate load capacity is not the same as my reference.

Here some summary of my reference journal as my understanding :

1) For material properties of steel and concrete, my reference journal use stress strain curve

2) There is concrete damaged plasticity model for nonlinear behaviour, it need several parameter (e.g. dilation angle, flow potential eccentricity, viscoplastic, etc). im not using it cause I don't know how to input that in ANSYS

3) There is restraining bending moment by supports at column ends. I don't know how to input in that ANSYS too

I already ran the model but the size more than 2GB, so i clear the generated data.

I want to apply this FE model for my undergraduate thesis. I m new using ANSYS, kindly help me solve this.

• Wenlong
Ansys Employee

1) For steel material, you can simply use an elastic + plastic material model. The default structural steel material does not have plasticity so you want to add a maybe bilinear hardening to the material model. For concrete material, you may want to consider the hydrostatic effect (constraining effect that increases the concrete strength) plasticity, and damage. You may consider the Drucker-Prager material. This would probably be the most time-consuming part of your thesis.

2) Microplane material is one that can consider plasticity and damage for concrete. However, it needs commands to define in ANSYS Mechanical (It cannot be defined through GUI).

3) You can use a "remote force" to apply this restraining bending moment, and set the remote point constraint behavior to "coupled" or "rigid".

Hope these help.

Regards,

Wenlong

Subscriber

Thank you very much Mr.Wenzhang for your response

I have already used multilinear isotropic hardening for steel material, here the picture

1) I found this reference to calculate Drucker-Prager model for concrete with 54 MPa compressive strength. I want to use the calculation for concrete with 186 MPa compressive strength (data from my 1st reference). Is it valid?

3) To obtain load capacity of the coloumn, i use remote displacement as load (as recomended from here).  How to add the restraining bending moment per load step if i use remote displacement as load (my reference only shows the correlation between restraining bending moment and axial load)?