Self-consistent crystal plasticity

Visco-Plastic Self-Consistent crystal plasticity model (VPSC) is one of the most successfuly crystal plasticity model that is widely used in the community of material science and engineering where people seek for a way to link microscopic mechanical properties to their macroscopic counterparts. This model is extensively studied in MFL.

Phenomenological constitutive model

Phenomenological approach using anisotropic yield functions and simple hardening rule has been widely used both in academia and industry. Development of accurate constitutive models for efficient yet accurate model is often required.

Forming limit prediction for sheet metals

Forming limit of a sheet metal is a mechanical property that can tell to what extent the metal sheet can be deformed before material faiture (such as fracture, or strain-localization) occurs. We are currently capable of calculating the theoretical forming limits using both crystal plasticity models and phenomenological models. Predictions of forming limit is very beneficial as actual experimental measurement is very costly and may consume a large volume of testing specimens. Sometimes, it is even impossible to experimentally determine the forming limits due to a certain geometry of given metal sheets. For example, a very thin ferritic stainless steel cannot be easilly tested using Erichsen tester!

Finite-Element simulations for metal forming operations

Practice of Finite Element simulation on forming operations has become a customary process prior to actual die-making process in order to reduce manufacturing cost and time. We develop material models and offer both numerical and experimental methods to characterize them for forming operations. The model is coded as a User MATerial subroutine (UMAT) for finite element simulations using ABAQUS.

Residual stress measurement on the basis of X-ray diffraction

Residual stresses arise due to heat treatment and plastic deformation, which is often unwated since it may lead to prematured failure of materials. Moreover, the same method has been used to measure quasi-static flow stress under multiaxial loading conditions where conventional measurement methods using load-cell is not applicable.