Imperial College London

DrZhushengShi

Faculty of EngineeringDepartment of Mechanical Engineering

Advanced Research Fellow
 
 
 
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Contact

 

+44 (0)20 7594 1806zhusheng.shi

 
 
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Location

 

705City and Guilds BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Zhang:2022:10.1177/10567895221105655,
author = {Zhang, R and Shi, Z and Yardley, VA and Lin, J},
doi = {10.1177/10567895221105655},
journal = {International Journal of Damage Mechanics},
pages = {1373--1395},
title = {A CDM-based unified viscoplastic constitutive model of FLCs and FFLCs for boron steel under hot stamping conditions},
url = {http://dx.doi.org/10.1177/10567895221105655},
volume = {31},
year = {2022}
}

RIS format (EndNote, RefMan)

TY  - JOUR
AB - Forming limit curves (FLCs), which are constructed using the limit strains at localised necking, are the most widely used tools for the evaluation of the formability of sheet metals. Fracture forming limit curves (FFLCs) are more recently developed, complementary tools for formability evaluation which are instead constructed using the limit strains at fracture. Since the formability depends strongly on forming conditions such as strain state, temperature and strain rate, models for predicting FLCs and FFLCs are essential for the optimisation and further application of hot forming processes in which these forming conditions vary significantly with both position and time. However, no model has so far been developed to predict FFLCs either alone or in conjunction with FLCs for sheet metals such as boron steel under hot stamping conditions. In this study, a set of unified viscoplastic constitutive equations for the prediction of both FLCs and FFLCs based on continuum damage mechanics (CDM) has been formulated from a set of recently developed constitutive equations for dislocation-based hardening, in combination with two novel coupled variables characterising the accumulated damage leading to localised necking and fracture. The novel variables take into account the effects of strain state, temperature and strain rate on the formability of sheet metals. The material constants in the CDM-based constitutive equations have been calibrated using experimental data comprising true stress-true strain curves and limit strains of a 22MnB5 boron steel obtained at a range of temperatures and strain rates. Investigation of the effect of varying selected parameters in the coupled damage variables on the resulting computed FLCs and FFLCs has demonstrated the flexibility of the model in enabling curves of different shapes and numerical values to be constructed. This indicates the potential of the CDM-based constitutive model for application to other materials for warm or hot stamping pr
AU - Zhang,R
AU - Shi,Z
AU - Yardley,VA
AU - Lin,J
DO - 10.1177/10567895221105655
EP - 1395
PY - 2022///
SN - 1056-7895
SP - 1373
TI - A CDM-based unified viscoplastic constitutive model of FLCs and FFLCs for boron steel under hot stamping conditions
T2 - International Journal of Damage Mechanics
UR - http://dx.doi.org/10.1177/10567895221105655
UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000810035400001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR - http://hdl.handle.net/10044/1/97917
VL - 31
ER -