Based on your description, it seems you have a good setup for your composite model using ABAQUS. Given that your CAI simulations are yielding a load-displacement curve that is too stiff compared to the experimental results, there might be a few parameters you could investigate to reduce the compressive stiffness:

Remember that simulation models like this can be sensitive to several parameters, so it may take some time and iteration to match your experimental results well. It is important to perform a sensitivity analysis to understand which parameters impact your results most. A parametric study might be beneficial to hone in on the optimal values of these parameters for the closest correlation with your experimental results.

Enrico Rusli ,

If you post a photo of the diagram, we can help better.

However, try doing a sensitivity analysis on the mesh and interlayer stiffness.

Also compare Abaqus damage modes with Test. Does it match?

Good luck

Creating a Finite Element Method (FEM) model of a Low Velocity Impact (LVI) and Compression After Impact (CAI) experiment is a complex process that requires careful consideration of various factors. Here are some general steps that can be taken to create an FEM model for an LVI and CAI experiment:

1. **Define the geometry**: The first step in creating an FEM model is to define the geometry of the composite plate. This can be done using a CAD software or by importing a 3D model of the plate into the FEM software.

2. **Define the material properties**: The next step is to define the material properties of the composite plate, such as the Young's modulus, Poisson's ratio, and density. These properties can be obtained from material testing or from published literature.

3. **Create the mesh**: The composite plate must be divided into small elements in order to perform the FEM analysis. The mesh size and element type can affect the accuracy and computational efficiency of the simulation.

4. **Define the boundary conditions**: The boundary conditions of the simulation must be defined, such as the type of loading and the support conditions. For LVI and CAI experiments, the loading is typically applied using a drop tower or an Instron machine.

5. **Define the damage model**: The damage model used in the simulation can affect the accuracy of the results. There are several damage models available, such as the Hashin damage model and the Puck failure model.

6. **Run the simulation**: Once the FEM model is set up, the simulation can be run using the chosen FEM software. The results can be analyzed to determine the damage and deformation of the composite plate during the LVI and CAI experiments.

7. **Compare with experimental results**: Finally, the results of the simulation can be compared with the experimental results to validate the accuracy of the FEM model. If the results do not match, adjustments can be made to the model parameters to improve the accuracy of the simulation.

It is important to note that creating an FEM model for LVI and CAI experiments requires expertise in both composite materials and FEM analysis. It is recommended to consult with an expert in the field to ensure the accuracy and reliability of the simulation results.

Citations:

[1] https://www.simuleon.com/simulia-abaqus/

[2] https://www.3ds.com/products-services/simulia/products/abaqus/abaquscae/

[3] https://www.researchgate.net/post/Why-my-Abaqus-model-becomes-inflated

[4] https://youtube.com/watch?v=9IuEhywu8b8

[5] https://www.3ds.com/products-services/simulia/products/abaqus/abaqusexplicit/

[6] https://www.wolframalpha.com/input?input=parameters+to+reduce+compressive+stiffness+in+cae+simulation+of+composite+plate

To address your specific concern regarding the compressive stiffness in your FEM model of the LVI (Low-Velocity Impact) and CAI (Compression After Impact) experiment, here are some potential factors you can consider:

Remember that accurately simulating LVI and CAI experiments can be challenging due to the complexity of the material behavior and the dynamic nature of the impact and compression. It may require multiple iterations and adjustments to achieve a closer match between the simulation and experimental results.

Mohamad Khorashad Here is the comparison between the abaqus and experimental result. I have tried using denser and coarser mesh but the curve gradient does not change. As for the damage, the lvi delamination area is bigger on the simulation, but the peak force is similar as seen in the lvi curve.

Enrico Rusli,

It is good, but CAI, as you said is very stiff!

How about other damage modes, like fiber fracture and matrix cracking?

Also, you can contact me through Skype to check your model.

Good luck