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Low velocity impact (LVI) and subsequent compression after impact (CAI).

Raz Offir




Low velocity impact (LVI) and subsequent compression after impact (CAI) of composites are important characteristics of aerospace materials. The primary focus of our research is to predict and understand the damage mechanisms in composite laminates, leveraging finite element analysis (FEA) techniques and sophisticated micromechanical modeling.

This research is pivotal for applications where composite materials may be subjected to impact and compressive loads due to impact of debris, as often needed in aerospace industry.

Micromechanical Modeling:

Before conducting the LVI analysis, we calculate the effective properties of each layer within the composite laminate. This is achieved using micromechanical models, which allow us to predict the behavior of the composite material by considering the properties and interactions of its constituent materials—typically fibers and matrix. These models enable the determination of effective stiffness, strength, and other critical properties that influence the overall performance of the laminate.

Micromechanical Modeling:

In the LVI analysis, we simulate the impact event on the composite laminate using finite element analysis. This involves modeling the impactor and the target laminate, considering parameters such as impact velocity, impactor mass, and boundary conditions. The primary data obtained from the LVI simulations include force vs. time and force vs. displacement responses. These data points are crucial for understanding the dynamic response of the laminate to impact. Additionally, we measure the response at specific points on the laminate to gain insights into localized damage phenomena.

Damage Prediction:

Our damage models are designed to predict the initiation and progression of damage within the composite material. These models take into account various failure mechanisms, including fiber breakage, matrix cracking, and delamination. We also incorporate cohesive zone models to predict interlaminar damage, which is the separation between the layers of the laminate. By accurately predicting these damage mechanisms, we aim to understand how the composite material will perform under impact conditions and identify potential weaknesses in the material design.

Compression After Impact (CAI) Analysis:

Following the LVI analysis, we conduct CAI simulations to evaluate the residual strength and performance of the impacted laminate. The CAI analysis simulates the compressive loading on the damaged laminate to assess its ability to withstand further mechanical stress. This analysis helps in understanding the extent of damage induced by the impact and its effect on the overall structural integrity of the composite.

Validation and Comparison with Experimental Results:

To ensure the accuracy and reliability of our simulations, we compare the results of our LVI and CAI analyses with experimental test data.

The comparison is made for the same parameters found in the simulations.

By comparing the simulated results with real test outcomes, we validate our models and refine our predictive capabilities.


Our research integrates advanced simulation techniques, robust damage models, and thorough experimental validation to predict and understand the behavior of composite materials under impact and compressive loads. This work not only enhances the predictive accuracy of composite material performance but also contributes to the development of safer and more reliable composite structures in various engineering applications. Through continuous improvement of our models and methods, we strive to push the boundaries of composite material research and innovation.

Representative Results:

Related Publication:


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