List of Abstracts 2022: SESSION E - MATERIAL MODELS AND MODELING OF TECHNOLOGICAL PROCESSES
Date: September 8, 2022
Fuel economy, crashworthiness and relevant stiffness require in transport application of advanced material with higher strength, good formability, and fatigue and corrosion resistance. These products currently referred as “Advanced High Strength Steels” (AHSS) are currently developed. AHSS represents multiphase steels which possess a composite microstructure comprised of ferrite, bainite, austenite and martensite. There is as well paid attention to lightweight materials as aluminium and lithium (electric vehicle battery pack).
With the increased application of these materials in transport and mainly automotive industries, new challenges in metal forming process will increase demand for more precise numerical modelling of the forming process and safety evaluation.
Part of these activities involve development and application of new material models including the description of hardening, plasticity surface and fracture initiation.
Current work is a part of this initiative creating reliable models of hardening based on performed experiments. The combination of PYTHON scripts, ABAQUS and ISIGHT is used for this task.
The paper describes the general approach to material calibration for different simulations - full cash, quasistatic and NVH. The approach is demonstrated based on the latest project calibration of UD, SF GF composite and aluminium. The different aspects of calibration are discussed - testing, analytic conversion or optimization approach and final validation.
Quenching is a critical heat treatment operation in the manufacturing process that enhances fatigue durability and wear resistance of carburized steel components, like power-transmitting gears. A high pressure gas quenching preceded by low pressure carburizing has been recognized recently as a technology having many advantages compared to traditional gas carburizing followed by hardening in liquid quenchants.
In this study, the results of computational finite element analyses of oil and gas quenching of a Pyrowear 53 steel are presented and confronted by experimental values. Material input was prepared using JMatPro, and the properties computed using the CALPHAD method were corrected by values obtained from physical experiments. DEFORM-3D was used as simulation software. Pyrowear 53 steel is typically used for applications requiring resistance to tempering at elevated temperatures, such as aerospace gearbox components. The lack of available literature data on this material and its use in such demanding and responsible structures as aerospace transmissions components justify the choice of subject material and the need for work on improving its manufacturability.
Standard Navy C-ring specimens were used to examine internal stress evolution during the high pressure gas quenching of the steel and the geometric distortion at the final stage. Dimensional changes of C-rings are assumed to reflect actual parts' behaviour under certain process conditions and may be used as a good indicator of actual processes parameters influence.
Simulation results correlate well with values obtained from the physical measurement, which imposes the quality of input data and simulation procedure setup.
The investigation of the production process and following mechanical loading of wire products were performed by using a combined approach between experiments and FE simulation. The success of simulation is based on the accurate description of the material model mainly the plastic behaviour of the material. In general, plastic data are obtained from tensile test specimens. Extension of plastic data to the higher strain can be done by means of modification of the material data on the basis of the comparison with measured forces during tested samples. The limitation of the plastic data in fracture strain was also determined on the appropriate tests. DEFORM software was used for confirmation of data correctness. The evaluated data were used to simulate wire drawing production, torsion of rods and high rotating forgings within the TORBO project.
Advanced High Strength Steels (AHSS) are often used in the automotive industry to enhance passenger safety. These steels represent a good compromise between strength, ductility and toughness. They play an active role in reducing the weight of the car and thus in reducing CO2. They are still one of the best solutions to achieve this goal. These AHSS include the complex phase steel CP1200 and the two-phase steel DP1000, which show an excellent combination between strength and ductility. Another equally important technological parameter is the susceptibility to cracking from contours. This paper presents measurements and material model development for use in FEM software. The emphasis is mainly on correct describing the anisotropic behavior of the material in tension, including its susceptibility to cracking. Various standardized, non-standardized as well as special technological tests are used for this behavior.