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Item type:Publication, Access status: with files , Thermoelastic modelling of the skin at finite deformationsThe modelling and computation of the coupled thermal and mechanical response of human skin at finite deformations is considered. The model extends current thermal models to account for thermally- and mechanically-induced deformations. Details of the solution of the highly nonlinear system of governing equations using the finite element method are presented. A representative numerical example illustrates the importance of considering the coupled response for the problem of a rigid, hot indenter in contact with the skin.Publicationtype: Journal ArticleScopus© Citations 28 257 342 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Structure-property relationships in nanoporous metallic glasses(Elsevier, 2016-01-21); ; ; ; We investigate the influence of various critical structural aspects such as pore density, distribution, size and number on the deformation behavior of nanoporous Cu64Zr36glass. By using molecular dynamics and finite element simulations an effective strategy to control the strain localization in nanoporous heterostructures is provided. Depending on the pore distribution in the heterostructure, upon tensile loading the nanoporous glass showed a clear transition from a catastrophic fracture to localized deformation in one dominant shear band, and ultimately to homogeneous plastic flow mediated by a pattern of multiple shear bands. The change in the fracture mechanism from a shear band slip to necking-like homogeneous flow is quantitative interpreted by calculating the critical shear band length. Finally, we identify the most effective heterostructure with enhanced ductility as compared to the monolithic bulk metallic glass. The heterostructure with a fraction of pores of about 3% distributed in such a way that the pores do not align along the maximum shear stress direction shows higher plasticity while retaining almost the same strength as the monolithic glass. Our results provide clear evidence that the mechanical properties of nanoporous glassy materials can be tailored by carefully controlling the design parameters.Publicationtype: Journal ArticleScopus© Citations 103 248 414 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Elastic and plastic poisson’s ratios of nanoporous gold(2015-08-19); ; ; ; We explore the elastic and plastic Poisson’s ratios, mE and mP, of nanoporous gold, using digital image correlation during compression experiments including load/unload segments. The two coefficients differ significantly, with mE independent of the ligament size, L, and with a trend for mP / L at not too large L. Disorder in the network of ligaments may explain why mE is smaller than predicted by lattice-based models. Finite element simulations, based on the Deshpande–Fleck constitutive law, validate the data analysis. The constitutive law captures work-hardening and transverse flow of nanoporous gold in good agreement with the experiment.Publicationtype: Journal ArticleScopus© Citations 64 478 545 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Crashworthiness of magnesium sheet structures(Trans Tech Publications, 2013-07); ; ; ; A hollow rectangular profile, as an example of a typical structural component made of magnesium alloy sheets has been built, tested and evaluated in order to assess its behaviour during axial crushing. The profiles were joined from plane sheets of AZ31 and ZE10, respectively, by laser beam welding and were then tested in compression. Numerical simulations have been conducted to understand the complex interplay between hardening characteristics of the materials under investigation, profile cross-section variation and energy absorption. The results from the compression testing of the profiles show that the welds are not the source of damage initiation and failure. The performance of the magnesium profiles in terms of dissipated specific energy is confirmed for small and intermediate displacements to be comparable to that of aluminium profiles. For large displacements, however, the shear-type failure mode of magnesium causes a sharp drop of the crushing force and thus limits the energy absorption. These findings demonstrate the requirement for an alloy and wrought magnesium process development specifically for crash applications which aims at progressive hardening along with high ductility for improving the bending and shear behaviour.Publicationtype: Conference Paper262