Finite Element Analysis of Collapse of Metallic Tubes

Quasi-static axial and lateral compression tests were conducted on aluminium tubes of circular,rectangular, and square cross sections on a universal testing machine (Instron model 1197).During the compression process, different tubes were collapsed in different modes of collapse.These compression processes were also modelled using FORGE2 finite element code. The codehas the capabilities of automatic mesh generation, modelling of die, creation of material data file,carrying out the finite element computations, and post-processing of results. The deformingtube material was modelled as rigid-visco-plastic. Development of different modes of collapsewas investigated experimentally and computationally. The experimental load-compression curvesand deformed shapes are compared with the computed results and found in good agreement.It is found that the proposed finite element models of the different compression processes arecapable of predicting the modes of collapse

Adaptive Finite-element Analysis of Plastic Deformation of Plates under Projectile Impact

This paper deals with the finite-element analysis of plastic deformation of plates during normal impact of projectile on plates, The finite element method implemented here is based on the flow formulation of plasticity. During projectile impact the geometrical configuration of domain is progressively altered that generally causes distortion of mesh. It affects the accuracy of finite-element solution, Hence, a posteriori error estimation for the computed finite-element solution has been incorporated to capture the zones of high stress and strain gradients. The h-refinement of the mesh is carried out over such domain to limit the solution error, Two projectile impact problems on a circular aluminium plate-one by a blunt-end projectile and another by a hemi-spherical-headed projectile-are analysed to illustrate the proposed method

Behaviour of Thin Aluminium Plates Subjected to Impact by Ogive-nosed Projectiles

A pneumatic gas gun has been used to fire ogive-nosed projectiles on aluminium plates(1mm) at varying impact velocities above the ballistic limit. Impact and residual velocities havebeen measured. Deformation of the target plate was studied. Experimental results formed thebasis of a subsequent finite element analysis of the problem using the ABAQUS 6.3 code. TheJohnson-Cook plastic flow and fracture model available in the code were utilised. Explicit finiteelement analysis has been performed to model the perforation phenomenon. Numerical resultswere significantly improved by reducing the element size up to a certain level beyond which nosignificant variation in the results was observed. Adaptive meshing has been found to be usefulin obtaining the accurate results and avoiding the problem of premature termination of theprogram due to excessive element distortion. Experimental and numerical results are comparedand a good agreement between the two has been found

Key Determinants of Sustainable Product Design and Manufacturing

AbstractIn the present era, there is an urgent need to make all industrial products sustainable for reduce environmental impact in the Production and consumption. Sustainable manufacturing is becoming crucial for businesses more than ever before. In this context, The key determinants of sustainable Product Design and manufacturing (SPDM) has been examined in the form of Environmental, Economical and Social factors in the Indian manufacturing organisations which provides the basis of SPDM for Indian manufacturing firms. This paper identified the various types of key determinants of Sustainable Product Design and Manufacturing (SPDM) by the survey methodology. A survey is conducted to confirm the key determinants in Indian manufacturing organisations. From this study it is proposed that the more emphasis should be given on Product life cycle, 6R (reuse, recover, recycle, redesign, reduce and remanufacture) and Housing and service infrastructure for this the new tools and techniques will be develop for creating a sustainable product. In this regards, it is suggested that proposed key Determinants play a vital role in product design and manufacturing and gives the better approach for sustainability

2d gravity stress tensor and the problem of the calculation of the multi-loop amplitudes in the string theory

It is shown that the vacuum value of the $2d$ gravity stress tensor in the free field theory is singular in the fundamental region on the complex plane where the genus-$n>1$ Riemann surface are mapped. Because of the above singularity, one can not construct modular invariant multi-loop amplitudes. The discussed singularity is due to the singularity in the vacuum value of the $2d$ gravity field that turns out to be on the genus-$n>1$ Riemann surfaces.Comment: 13 pages, LATEX, November 199

Observing Long Colour Flux Tubes in SU(2) Lattice Gauge Theory

We present results of a high statistics study of the chromo field distribution between static quarks in SU(2) gauge theory on lattices of volumes 16^4, 32^4, and 48^3*64, with physical extent ranging from 1.3 fm up to 2.7 fm at beta=2.5, beta=2.635, and beta=2.74. We establish string formation over physical distances as large as 2 fm. The results are tested against Michael's sum rules. A detailed investigation of the transverse action and energy flux tube profiles is provided. As a by-product, we obtain the static lattice potential in unpreceded accuracy.Comment: 66 pages, 29 figures, uuencoded latex file with epsfigures (450 K), supplementary full colour figures are available via ftp, CERN-TH.7413/94 (extended version

Behaviour of stock returns in the KLSE: A test of the random walk hypothesis

A sample of 224 companies listed in the Kuala Lumpur Stock Exchange was taken for the period 1991-96. The serial correlations tests of varying lags and the runs tests were employed to test for the random walk theory. The bulk of the results tilts towards the rejection of non-randomness, lending weight to the argument that the stock market has no memory, and casting doubt upon the usefulness of technical analysis

CAPM or APT? A comparison of two asset pricing models for Malaysia

This study uses monthly return data on 213 stocks listed on the main board of Kuala Lumpur Stock Exchange, Malaysia for the period September 1988 to June 1997 to compare two frequently cited asset pricing models: the capital asset pricing model, CAPM and the arbitrage pricing theory, APT. A comparison was performed along the lines of Chen (1983) and the results showed the APT to perform better than the CAPM in explaining the variations in cross section of returns. The implication for investors is that the market index is but one of several sources of risk , which should be taken into account in any decision governing investment in the stock market

A comprehensive lattice study of SU(3) glueballs

We present a study of the $SU(3)$ glueball spectrum for all $J^{PC}$ values at lattice spacings down to $a^{-1}=3.73 (6)$ GeV ($\beta=6.4$) using lattices of size up to $32^4$. We extend previous studies and show that the continuum limit has effectively been reached. The number of clearly identified $J^{PC}$ states has been substantially increased. There are no clear signals for spin-exotic glueballs below 3 GeV. A comparison with current experimental glueball candidates is made.Comment: 10 pages including 2 PS figures, Liverpool Preprint: LTH 303, Wuppertal Preprint: WUB 93-1

The Matter and the Pseudoscalar Densities in Lattice QCD

The matter and the pseudoscalar densities inside a hadron are calculated via gauge-invariant equal-time correlation functions. A comparison is made between the charge charge and the matter density distributions for the pion, the rho, the nucleon and the $\Delta^+$ within the quenched theory, and with two flavours of dynamical quarks.Comment: Typos corrected; 13 pages, 16 figure