Stating Failure Modelling Limitations of High Strength Sheets: Implications to Sheet Metal Forming

Area of Science:

• Materials Science
• Mechanical Engineering
• Computational Mechanics

Background:

• High strength sheet steels are crucial in modern manufacturing.
• Accurate fracture modeling is essential for predicting material behavior and ensuring structural integrity.
• Existing strain-driven ductile fracture models require validation for pre-damaged materials.

Purpose of the Study:

• To assess the accuracy of strain-driven ductile fracture models in simulating damage and fracture evolution in high strength sheet steel.
• To validate numerical simulations against experimental data for both undamaged and pre-damaged specimens.
• To identify limitations of current models and propose areas for improvement.

Main Methods:

• Numerical modeling of standard fracture mechanical tests.
• Implementation of a specific failure and damage model to simulate material response.
• Experimental validation of simulation results using laboratory testing data.

Main Results:

• The damage and failure model accurately predicts fracture evolution in undamaged specimens.
• For pre-damaged specimens, the model over-predicts displacement at crack initiation by an average of 28%.
• A significant discrepancy exists between simulated and experimental results for pre-damaged materials.

Conclusions:

• The current damage and failure model is suitable for undamaged high strength sheet steel but requires enhancement for pre-damaged conditions.
• An extended model incorporating crack tip fracture mechanisms is needed for improved accuracy.
• Such advancements will enhance fracture testing procedures and the modeling of sheet metal manufacturing processes.