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The explicit nonlinear dynamic relaxation method (DRM) is applied to the nonlinear geodesic shape finding analysis by introducing fictional tensioned \'strings\' along the desired seams with a three or four-node membrane element. A number of results from the numerical example for the nonlinear geodesic shape finding and patterning analysis are obtained by the proposed method to demonstrate the accuracy and efficiency of the developed method. Therefore, the proposed geodesic shape finding algorithm may improve the applicability of a four-node membrane element to membrane structural engineering and design analysis simultaneously for the shape finding, stress, and patterning analysis.

A study on the free-vibration analysis of plates and shells is described in this paper. In order to determine the natural frequencies of plates and shells, a nine-node degenerated shell element is developed by using the degenerated solid concept based on Reissner–Mindlin (RM) assumptions which allow the shear deformation and rotatory effect to be considered. All terms required in the shell finite element (FE) formulation are defined in the natural domain. In particular, assumed natural strains are derived to alleviate the locking phenomena inherited in the RM shell elements. The natural constitutive equation is used in conjunction with the natural strain terms. The proposed shell FE formulation offers significant implementation advantages since it consistently uses the natural co-ordinate system. Various numerical examples are carried out and its results are then compared with the existing exact solutions and the numerical solutions calculated by other shell FEs.

To identify the sensitivity and the patterns of change in sensory excitability that accompany an ischaemic insult.Sensory excitability studies were undertaken in 10 subjects (mean age 36), and monitored throughout ischaemia and following its release. Ischaemia was induced using a sphygmomanometer inflated to 200mm/Hg above the elbow.During ischaemia there was reduction in threshold (P0.001), associated with a significant increase in refractoriness (106+/-6.62%; P0.001), reduction in superexcitability (30.4+/-0.42%; P0.001), and 'fanning in' of threshold electrotonus, all indicative of axonal depolarization. Paraesthesiae were minimal during ischaemia, but became severe on release, at which stage numbness was prominent. Late subexcitability in sensory axons was completely abolished by a relatively shorter period of ischaemia than previously observed in motor axons.The present study has successfully developed a template for changes in sensory axonal excitability parameters that accompany ischaemia, and established their relative sensitivity to an ischaemic change. Further, it is proposed that the inhibition of the Na+/K+ pump, in the setting of increased persistent Na+ currents and abolition of late subexcitability may underlie the development of paraesthesiae during ischaemia.Changes in axonal excitability induced by ischaemia may serve as a tool to identify and interpret changes in axonal membrane potential recorded in neuropathic patients.