Expert systems and finite element structural analysis - a review

Finite element analysis of many engineering systems is practised more as an art than as a science . It involves high level expertise (analytical as well as heuristic) regarding problem modelling (e .g. problem specification,13; choosing the appropriate type of elements etc .), optical mesh design for achieving the specified accuracy (e .g . initial mesh selection, adaptive mesh refinement), selection of the appropriate type of analysis and solution13; routines and, finally, diagnosis of the finite element solutions . Very often such expertise is highly dispersed and is not available at a single place with a single expert. The design of an expert system, such that the necessary expertise is available to a novice to perform the same job even in the absence of trained experts, becomes an attractive proposition. 13; In this paper, the areas of finite element structural analysis which require experience and decision-making capabilities are explored . A simple expert system, with a feasible knowledge base for problem modelling, optimal mesh design, type of analysis and solution routines, and diagnosis, is outlined. Several efforts in these directions, reported in the open literature, are also reviewed in this paper

Consistency aspects of out-of-plane bending, torsion and shear in a quadratic curved beam element

Curved beams in civil engineering applications call for out-of-plane bending and torsion under the action of13; out-of-plane transverse shear loads. The design of a quadratic displacement curved beam element capable of13; representing shear deformation as in the Timoshenko beam theory requires special attention to the manner in which the shear strain is represented. Field-inconsistent representations of the out-of-plane transverse shear strain will result in a loss of efficiency and introduce spurious oscillations in the bending moment, torsional moment and shear force. The optimal field-consistent assumed strain interpolation for shear is derived and it is demonstrated to posses very high accuracy which is free from spurious force and moment oscillations

E-resources usage and research productivity

The best performing laboratories in the CSIR from the point ofview of optimally accessing and using e-resources are identified using performance indicators derived from number of scientists in the laboratory, number of downloads during a prescribed window, number of publications during the same window and the total citations earned by these papers during a citation window of one year following the publications window

From ‘The Book of Life’ to ‘Freedom of Belief’

India continues to stand at the cross-roads of having to choose from the two roads that lead to Belief. For Belief can be founded on Faith, or it can be founded on Reason. Faith is a non-rational belief system. Science is a rational belief system. One of the ironies of life that is seriously emerging from recent research in evolutionary biology is that the acceptance of non-rational belief systems confers a greater ability to survive. At the same time, a society that has no rational thinkers will probably be wiped out. Therefore, for long term survival, every social group needs a small group of individuals who have the rational compass to guide the rest on the Road to Reason, and away from the Road of Faith that is pot-holed with mindless superstitions and rituals. Without this, we would be condemned to lead narrow-minded lives of quiet desperation

Field consistency and the finite element analysis of multi-field structural problems

We introduce the concept of field consistent representation of continuum problems in structural mechanics which require definition by more than one field variable. In some practical situations, the engineering dimensions of the problem require that the many field variables needed to model the deformation of the continuum may have to be constrained among themselves in a suitable way, If this is not properly accommodated in the finite element model, severe errors can result. Here, we consider a new terminology for such errors and examine a simple case in which such errors can lead to the locking phenomenon, Techniques, most of which originated on an ad-hoc basis even before the mechanics of field-consistency was established, can now be re-interpreted to show how they successfully introduce a consistent representation of the constrained strain-fields and thus remove the 'spurious constraints' that lead to 'errors of the second kind'