Marc accurately predicts results of dynamic tensile extrusion test

In a wide range of industrial and defense applications, material are required to perform at extreme operating conditions involving large plastic deformation, high strain rates, elevated temperatures and severe dynamic pressure. Some examples of this application are perforating guns in the oil and gas industry, debris impact in aerospace engineering and ship collisions in naval engineering.

Challenge

The high cost of building and testing prototypes for applications operating under extreme conditions and the difficulty of acquiring data during physical testing makes accurate simulation critical. A key challenge is the development of material models that maintain their accuracy while the material is subjected to extreme conditions. For this reason, much of the information about the response of the material is obtained after the fact and is used to validate the model and tune its material characteristics parameters.

TECHDYN researchers set out to develop a new material model that could be used to accurately predict the performance of materials under extreme conditions. In this test, a projectile is shot into a conical die with an exit opening smaller than the diameter of the projectile. It is subjected to very large deformations and high strain rates. As the projectile deforms, the material is dynamically extruded, producing a material jet that travels as much as twice as fast as the initial speed of the projectile. TECHDYN needed to find a FEA solution that could handle the large deformation and strains involved in the problem.

Solution

“We prefer Marc implicit FEA software because it provides substantially greater accuracy than any alternative we are aware of. We have found computational times to be reasonable considering the complexity of the underlying physics. Marc Also simplifies the process of implementing complex material models with its user defined function capabilities.” Said Nicola Bonora, Chief Executive Officer of TECHDYN Engineering. 

The material jet stretches as a result of the velocity difference between the tip and tail. The number, size and shape of the fragments produced at an initial velocity of 400 m/s was used to validate the simulation.

Now that TECHDYN has validated their material model and ability to simulate extreme conditions, the company is preparing to offer engineering consulting services using Marc with the new material model to provide accurate simulations of extreme conditions.