题 目：Anisotropic responseof 3D-printed polymeric lattices subjected to quasi-static and impact crushingalong different directions
时 间：2026年1月17日，上午10：00－11：30
地 点：交通大楼604会议室
报告人：Victor P.W. SHIM 教授（新加坡国立大学）
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土木与交通学院
2026年1月15日
报告人简介：
Prof.Victor Shim is an Emeritus Professor of Mechanical Engineering at the NationalUniversity of Singapore (NUS), as well as a Professor in the Faculty ofMechanics and Engineering Science at Ningbo University. He established theImpact Mechanics Laboratory at NUS, and his research interests include impactmechanics, dynamic material behavior, constitutive modeling, cellularmaterials, 3D-printed lattices, penetration of high-strength fabrics, andimpact on protective structures. He has been an Editorial Board Member of theInternational Journal of Impact Engineering since 1999, and one of itsAssociate Editors since 2008. He is also on the Editorial Board of DefenceTechnology. Supported by a scholarship from the New Zealand government, heobtained his Bachelor’s degree with First Class Honors from the University ofAuckland. He pursued a Master’s degree at NUS, then obtained a scholarship forhis PhD studies at Cambridge University. He has been a Visiting Scientist atthe Tokyo Institute of Technology, a Visiting Scholar at the University ofCalifornia, San Diego, and a Visiting Professor at Hiroshima University. He hasgiven keynote and plenary talks at well-established conferences related toImpact Mechanics, such as IMPLAST, DYMAT and ICILLS. He has also served invarious university-level senior management appointments at NUS, such asAssociate Vice-President for Global Relations, Director of Corporate Relations,and also as a Vice-Dean of the Faculty of Engineering (which oversees all theEngineering Departments, such as Mechanical, Civil & Environmental,Chemical & Biomolecular, Materials Science & Engineering,Bioengineering, Industrial & Systems Engineering, etc). For hiscontributions to university education in Singapore, he was conferred a NationalDay Public Administration (Silver) Medal by the Singapore government in 2012.
报告摘要：
Strut-based lattices with different cubic cellarchitectures have been proposed to enhance their mechanical response toquasi-static and impact compression along their three principal geometricalaxes. Favorablebehavior for loading along these directions does not implysimilar performance for impact along other directions, and this aspect hasreceived relatively little attention. Nevertheless, this is important, because inactual applications, lattice-based components are likely to sustain loading orrequired to mitigate impact from any direction. Furthermore, lattices withcomplex cell geometries that are fabricated by additive manufacturing,generally display significant loading angle dependent mechanical propertiesbecause of the 3D fabrication process, resulting in anisotropy. Consequently,it is essential to examine the compressive responses of lattices loaded alongoblique directions, especially under impact, to identify the degree ofmechanical anisotropy for large deformation. In this study, 3D-printed samplesof Octet and Rhombic Dodecahedron lattices, as well as a hybrid descendantlattice (HS), are subjected to planar quasi-static and impact compression alongtheir principal geometric axes and two oblique directions – the face diagonaland body diagonal. Compared to the responses for compression along theprincipal geometrical axes, loading along oblique directions generate verydifferent stress-strain responses and crushing modes. This anisotropic behavioris linked to cell geometry and strut angle dependent material properties. Thenovel HS lattice displays a smaller degree of anisotropy, indicatingsuperiority in terms of more consistent behavior with regard to loadingdirection. The study also reveals different crushing patterns on adjacent sidesof lattices for oblique impact, and finite element modeling is used to analysethis. It is found that incorporation of printing direction dependent andrate-sensitive material properties is essential in obtaining globalstress-strain responses and deformation modes that match experiments. Thesimulations also show that the different deformation patterns for obliquecompression are caused by changes to the loading mode on cell struts, whichdiffers from that for compression along the principal geometrical axes.
