Dr. M. S. Niazi
University of Twente
Faculty of Engineering Technology
Chair of Production Technology
P.O. Box 217
7500 AE Enschede
P +31 (0)53 489 4175
F +31 (0)53 489 3471
FibreChain (European Project)
Start / End:
January 2013 to July 2014
Lightweight components and their energy-efficient production is one of the most important key factors to fulfill the ever increasing global demands. Nowadays, for 3D-shaped, multi-layered products based on flexible materials only specialized and semi-automated manufacturing equipment is available. The FibreChain project aims at the development of worldwide first automated turnkey manufacturing systems for fibre-reinforced thermoplastic composites (FRTC) addressing public and private transportation, mechanical, chemical and civil engineering as well as consumer goods.
One task of the FibreChain project is to develop optimization software tools to determine the process window for production processes of FRTC. The production processes of Laser Assisted Tape Placement (LATP) and thermo-forming of FRTC are taken as examples in this work package. The optimization problem of LATP has been setup in ANSYS 13.0 Workbench, utilizing the CFD and Design optimization module to determine the process window.
Plasticity induced anisotropic damage modeling for forming processes.
Start / End:
January 2009 to December 2012
Cum Laude for PhD.
ESAFORM PhD prize for industrial research and outstanding contribution to material forming.
Stringent carbon emission targets and consumer demands for highly fuel efficient and safe vehicles are driving most of the innovations in the automotive industry. In the present era, the prime technological goal of the automotive industry is to design and manufacture commercially viable lightweight vehicles while maintaining the structural performance of the vehicles at the same time. Development of Advanced High Strength Steels (AHSS) is an important step forward in this context. However, plastic deformation induces damage in AHSS. Damage development during the forming process renders the classical failure prediction techniques ineffective, which poses difficulties in designing the forming process. Therefore damage development in these steels has been studied and incorporated in numerical simulations for accurate failure predictions in forming processes and for determination of the product properties after forming.
Damage development is anisotropic by nature and shall be considered anisotropic for accurate failure predictions. In this research, anisotropy in damage has been classified into two categories; Material Induced Anisotropy in Damage (MIAD) and Load Induced Anisotropy in Damage (LIAD). MIAD is related to the anisotropy in distribution and shape of second phase particles or impurities and is governed by void/crack nucleation. LIAD is related to the loading direction of the material. The phenomenon of MIAD was discovered during this research. This is the first research showing the occurrence of MIAD in AHSS.
The standard Lemaitre anisotropic damage model was modified to incorporate: lower damage evolution under compression, strain rate dependency in damage and Material Induced Anisotropic Damage (MIAD). Viscoplastic regularization of damage models was revisited. This technique proved to be effective in removing the pathological mesh dependence of local damage models. The damage model parameters for the same grade of DP600 were determined. The Modified Lemaitre’s (ML) anisotropic damage model was validated with experiments.
•Process parameter optimization
•Material deformation modeling