Failure Strain and Fracture Prediction During Shock Tube Impact Forming of AA 5052-H32 Sheet

Abstract

The present study deals with both numerical and experimental evaluation of failure strain and fracture pattern during shock tube impact forming of 1.5 mm thick AA 5052-H32 sheet. A hemispherical end nylon striker is propelled to deform the sheet at different velocities. Here the main objective is to understand the effect of flow stress models and fracture models on the forming outputs. The experimental situation is modelled in two stages, i.e., incorporating the pressure in the first stage, and displacement of the striker in the second stage in finite element simulation using the finite element (FE) code (DEFORM-3D). A new strategy followed to evaluate the rate-dependent flow stress data from the tensile test of samples sectioned from shock tube-based deformed sheet is acceptable, and finite element simulations incorporating those properties predicted accurate failure strain and fracture pattern. Out of all the flow stress models, the modified Johnson-Cook model has a better flow stress predictability due to the inclusion of the non-linear strain rate sensitivity term in the model. During the prediction of the failure strain and necking location, Cockcroft-Latham failure model, Brozzo failure model, and Freudenthal failure model have a fair agreement with experimental data in combination with the two flow stress models, i.e., Johnson-Cook model and modified Johnson-Cook model.

Constitutive Model and Fracture Criterion of Q345 Steel Welded Joints

“…According the test results in 3, the test points of fracture strain and triaxial stress of Q345 BMZ and HAZ material are shown in Figure 13, and the J-C fracture model is fitted by the least method. For Q345 BMZ material, when D 1 � 1.025, D 2 � −0.008, and D 3 � 3.617, the fitting curve is in good agreement with the experimental results, and the fitting formula is shown in equation ( 9); for HAZ materials, when D 1 � 0.678, D 2 � −2.689E − 5, and D 3 � 7.683, the fitting formula is shown in equation (10).…”

“…Bao et al [6,7] designed a series of tensile shear compression tests; B three Børvik et al [8] carried out the experiment and simulation of the stress and strain rate of thick steel plate and put forward the fracture criterion and the relationship between failure strain and strain rate; Vm [9] described the type of limit state, gave the experimental results of fracture toughness characteristics, and gave examples of application of reliability theory, risk analysis, and fracture mechanics to solve various application problems. Barik et al [10] carried out numerical and experimental study on the failure strain and fracture mode during the impact forming process of 1.5 mm thick AA 5052-H32 sheet. Akbari and Asadi [11] welded A356 aluminum pipe by friction stir welding and obtained the best FSW parameters according to the silicon particle size, hardness, and ultimate tensile strength of welded pipe.…”

An Enhanced Lemaitre Model and Fracture Map for Cr5 Alloy Steel during High-Temperature Forming Process

“…Qiang Li [ 13 ] used the Cockroft and Latham fracture criterion to study the surface cracking of Fe-Cu-C steel. Feuerhack et al [ 14 ] used the Cockcroft and Latham damage criterion to study crack location and shape during extrusion. Aditya Rio Prabowo et al [ 15 ] analysed the reliability of the Cockcroft and Latham damage criterion.…”