In-situ Effect in Cross-ply Laminates under Various Loading Conditions Analyzed with Hybrid Macro/Micro-scale...

Area of Science:

• Materials Science
• Computational Mechanics
• Solid Mechanics

Background:

• Composite materials, particularly cross-ply laminates, are susceptible to complex failure mechanisms.
• Understanding the in-situ effect, where neighboring plies influence local behavior, is crucial for accurate failure prediction.
• Existing analytical models may not fully capture the intricate interactions at the ply level.

Purpose of the Study:

• To investigate the in-situ effect on failure initiation and propagation in cross-ply laminates using multi-scale finite element analysis.
• To develop empirical formulas for calculating in-situ strengths based on ply thickness and orientation.
• To propose novel failure criteria that incorporate in-situ effects for predicting composite failure under multi-axial stress.

Main Methods:

• Three-dimensional (3D) hybrid macro/micro-scale computational models were developed.
• Multi-scale finite element analyses were performed under various loading conditions.
• A reverse fitting method was used to obtain material parameters for empirical formula development.

Main Results:

• Computational models accurately quantified the in-situ effect, showing good agreement with analytical predictions.
• Comparative studies revealed crack suppression mechanisms influenced by embedded ply thickness and adjacent ply orientation.
• Empirical formulas for in-situ strengths and new failure criteria were successfully developed.

Conclusions:

• The developed computational technique effectively predicts failure behaviors and strengths of cross-ply laminates by incorporating in-situ effects.
• The proposed failure criteria enhance the prediction accuracy for laminated composites under multi-axial stress states.
• This research provides a robust framework for designing and analyzing composite structures with improved reliability.