Some properties of unsteady unidirectional flows of a fluid of second grade are considered for flows impulsively started from rest by the motion of a boundary or two boundaries or by sudden application of a pressure gradient. Flows considered are: unsteady flow over a plane wall, unsteady Couette flow, flow between two parallel plates suddenly set in motion with the same speed, flow due to one rigid boundary moved suddenly and one being free, unsteady Poiseuille flow and unsteady generalized Couette flow. The results obtained are compared with those of the exact solutions of the NavierStokes equations. It is found that the stress at time zero on the stationary boundary for the flows generated by impulsive motion of a boundary or two boundaries is finite for a fluid of second grade and infinite for a Newtonian fluid. Furthermore, it is shown that for unsteady Poiseuille flow the stress at time zero on the boundary is zero for a Newtonian fluid, but it is not zero for a fluid of second grade.

Independent wire rope core (IWRC) is one of the fundamental components of complex wire ropes. It is a complex geometry and constructed by wrapping wire strands over a straight wire strand. The outer wires of the IWRC are double helical shaped feature which can be only modeled using special treatment. The aims of this paper are to introduce a new technique of modeling wire rope with IWRC and to compare numerical results obtained from this model with available results in the literature. Therefore the model generation for a simple straight strand is explained and accuracy of this model is validated. Furthermore this modeling procedure is adapted to whole wire rope structure considering double helical geometry concept. The proposed rope model gives remarkable results by means of wire by wire analysis scheme. This model is found easier and more effective. The results show good agreement with other available results but with a simpler and more practical approach.

Due to the complex geometry of wires within a wire rope, it is difficult to model and analyse independent wire rope core accurately (IWRC). In this paper, a more realistic three-dimensional modelling approach and finite element analysis of wire ropes are explained. Single helical geometry is enough to model simple straight strand while IWRC has a more complex geometry by inclusion of double helical wires in outer strands. Taking the advantage of the double helical wires, three-dimensional IWRCs modelling is applied for both right regular lay and lang lay IWRCs. Wire-bywire based results are gathered by using the proposed modelling and analysis method under various loading conditions. Illustrative examples are given for those show the accuracy and the robustness of the present FE analysis scheme with considering frictional properties and contact interactions between wires. FE analysis results are compared with the analytical and available test results and show reasonable agreement with a simpler and more practical approach.

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