development of a numerical model which describes launching of offshore jackets from barge is presented in this paper. in this model, in addition to capabilities of commercial softwares, water entry forces on jacket members and an implicit newmark solution technique are included. the results are in general agreement with other numerical software’s available (sacs). fluid forces acting on jacket ...

This paper studies nonlinear flutter of rectangular variable stiffness composite laminates (VSCLs) subjected to a low supersonic airflow. The VSCLs are formed by different individual laminae where polymeric matrix is reinforced curvilinear carbon fibres. plate’s displacement field follows Third-order Shear Deformation Theory (TSDT); p-version finite element employed discretize the components. A...

To reduce the vibration and deformation of large thin-walled workpieces during milling process, mirror is widely used due to its point-to-point support strong applicability. The influence head on workpiece’s dynamic characteristics crucial in determining whether process reliable effective. Therefore, this study establishes a time-varying model for with various boundary conditions accurately ana...

in this paper, the behaviour of buried pipelines under the effect of propagation of seismic waves and faulting is studied seperately. the stability of this type of structure was first studied by using three different methods proposed by newmark-hall, kenndey et al. and wang - yeh under the effect of ground faulting. by parametric study, the effect of soil types, size of pipeline, depth of embed...

In the real application of active control systems to mitigate the response of structures subjected to sever external excitations such as earthquake and wind induced vibrations, since the capacity of actuators is limited then the actuators saturate. Hence, in designing controllers for linear and nonlinear structures under sever earthquakes, the actuator saturation should be considered as a const...

Offshore oil and gas industry is blooming up towards the deep-water region of ocean deposit. Far off the continental shelf, the traditional jacket type fixed platform and bottom supported compliant platform are not suited to be economic offshore structure in deep water oil and gas exploration. Floating Spar platform is essentially most economic and efficient in these sea states. In the present ...

In this article the general non-symmetric parametric form of the incremental secant stiffness matrix for nonlinear analysis of solids have been investigated to present a semi analytical sensitivity analysis approach for geometric nonlinear shape optimization. To approach this aim the analytical formulas of secant stiffness matrix are presented. The models were validated and used to perform inve...

An important property of implicit time integration algorithms for structural dynamics is their tendency to “overshoot” the exact solution in first few steps computed response due high-frequency components initial excitations. The typical analysis technique overshooting involves study asymptotic algorithm's step limiting high frequency case. This article finds that prior much engineering literat...