A simple approach to plot photoelastic fringes in grey scale and also in colour from finite element (FE) results is presented for better recognition and comparison with experiments. This requires proper identification of the plotting variable from FE results. For comparison with transmission photoelasticity, post‐processing of principal stress difference is needed and for reflection photoelasticity the principal strain difference is to be used. The importance of the use of appropriate correction factors for comparison with reflection photoelastic results is emphasised. A newer approach to evaluate Rf for complicated geometries is indicated. Plotting of experimental fringes from finite elements is useful not only for validating the numerical model based on experiments but also for validating the experiments. To illustrate this, the problem of an interfacial crack in a bi‐material Brazilian disc is discussed.

SUMMARYA novel approach to plot photoelastic fringe contours from three-dimensional ÿnite element results is presented. Plotting of fringe contours from 3D FE models requires the calculation of secondary principal stresses along the light path. The deÿnition of secondary principal stresses and the calculation of relevant photoelastic data for fringe plotting are discussed. The plotting scheme uses a scanning approach and the evaluation of total fringe order is achieved by combining a ÿle structure and subsequent sorting of these data to enable integration along the light path. The methodology is validated for the problem of a cantilever beam with an edge load. The usefulness of the methodology to verify 3D FE modelling and for experimentalists to design their experiments is indicated.

The behavior of bodies subjected to impulse loading is of prime importance in the study of forces that occur in impulse facilities. Before performing the actual tests, theoretical and numerical simulations are carried out to obtain the response of bodies subjected to impulse loading. The simplest model for this study can be considered as a rod of circular cross section fixed at one end and free at other end. When a transient impulse load is applied on a body, vibrations occur in the body for the brief period of time. In this paper, the effect of a half sine impulse force applied on a cantilever rod in the axial direction has been discussed. The displacements at the tip of the rod were obtained based on two theories, the basic vibration formulae and FEM analysis. Simulations were performed using ANSYS and compared with the displacements obtained from the two theoretical methods.

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The accurate prediction of force is very important in the present scenario of aerodynamic force measurement. The high accuracy of force prediction during calibration facilitates a better accuracy of force measurement in aerodynamic facilities like shock tunnels and wind tunnels. The present study describes the force prediction in an accelerometer force balance system using support vector regression (SVR). The comparison of SVR with the existing force prediction techniques namely, adaptive neuro-fuzzy inference system (ANFIS) and artificial neural network (ANN) has also been carried out. The accelerometer force balance used in the current experimentation consists of a tri-axial accelerometer to measure the response on an aluminium hemispherical model on the application of force. The impulse forces were applied along the axial, normal and azimuthal directions. The forces were predicted using the accelerations obtained from the tri-axial accelerometer. SVR method was able to predict the forces quite accurately as compared to ANFIS and ANN. However, SVR has the advantage over ANFIS and ANN in that it is independent of the magnitude of the training and testing data. It is capable of an accurate prediction of forces with any magnitude of training and testing data, unlike ANFIS and ANN.