Modal analysis of novel coronavirus (SARS COV-2) using finite element methodology.

Many new engineering and scientific innovations have been proposed to date to passivate the novel coronavirus (SARS CoV-2), with the aim of curing the related disease that is now recognised as COVID-19. Currently, vaccine development remains the most reliable solution available. Efforts to provide solutions as alternatives to vaccinations are growing and include established control of behaviours such as self-isolation, social distancing, employing facial masks and use of antimicrobial surfaces. The work here proposes a novel engineering method employing the concept of resonant frequencies to denature SARS CoV-2. Specifically, "modal analysis" is used to computationally analyse the Eigenvalues and Eigenvectors i.e. frequencies and mode shapes to denature COVID-19. An average virion dimension of 63 nm with spike proteins number 6, 7 and 8 were examined, which revealed a natural frequency of a single virus in the range of 88-125 MHz. The information derived about the natural frequency of the virus through this study will open newer ways to exploit medical solutions to combat future pandemics.

Challenges and issues in continuum modelling of tribology, wear, cutting and other processes involving high-strain rate plastic deformation of metals.

Contribution of finite element method (FEM) as a modelling and simulation technique to represent complex tribological processes has improved our understanding about various biomaterials. This paper presents a review of the advances in the domain of finite element (FE) modelling for simulating tribology, wear, cutting and other processes involving high-strain rate plastic deformation of metals used in bio tribology and machining. Although the study is largely focused on material removal cases in metals, the modelling strategies can be applied to a wide range of other materials. This study discusses the development of friction models, meshing and remeshing strategies, and constitutive material models. The mesh-based and meshless formulations employed for bio tribological simulations with their advantages and limitations are also discussed. The output solution variables including scratch forces, local temperature, residual stresses are analyzed as a function of input variables.

On the Role of Contact and System Stiffness in the Measurement of Principal Variables in Fretting Wear Testing.

In this work, the role of the contact stiffness in the measurement of principal variables in fretting wear tests is assessed. Several fretting wear tribometers found in the literature, including one developed by the authors, are analysed and modelled using numerical methods. The results show the importance of the tribosystem stiffness and tangential contact stiffness in the displacement sensor calibration and in the correct numerical modelling of fretting wear tests, especially for flat-to-flat contact configuration. The study highlights that, in most cases, direct comparisons between fretting results with severe wear obtained with different tribometers cannot be performed if the contact stiffness is not properly considered during the development of the experiments.

Benchmarking of several material constitutive models for tribology, wear, and other mechanical deformation simulations of Ti6Al4V.

Use of an alpha-beta (multiphase HCP-BCC) titanium alloy, Ti6Al4V, is ubiquitous in a wide range of engineering applications. The previous decade of finite element analysis research on various titanium alloys for numerous biomedical applications especially in the field of orthopedics has led to the development of more than half a dozen material constitutive models, with no comparison available between them. Part of this problem stems from the complexity of developing a vectorised user-defined material subroutine (VUMAT) and the different conditions (strain rate, temperature and composition of material) in which these models are experimentally informed. This paper examines the extant literature to review these models and provides quantitative benchmarking against the tabulated material model and a power law model of Ti6Al4V taking the test case of a uniaxial tensile and cutting simulation.