A below knee (BK) prosthesis is a device used to compensate for missing limb segments in patients with BK amputations as an aid for locomotive and other daily activities It consists of three main parts: socket, shank, and artificial foot. The shank is merely a shaft of a suitable length to serve as a frame structure to transfer biomechanical forces between the socket and foot. In traditional BK prostheses, the shank is made from rigid metallic or composite material tube (Teflon), while in the current work, a modified version is suggested with internal stiffness and damping characteristics to act as energy storage and shock absorber. A mathematical model was thus employed to analyse the impact behaviour from walking gait, and the main parameters studied were the effective mass of impact, loading rate, and knee pre-swing angular velocity. The modified prosthesis was tested with a BK amputation patient and compared with a traditional prosthesis in force platform and treadmill tests. The results showed some improvement in patient gait parameters; at stance phase, it smoothed the GRF curve; at heel strike, both the effective mass of impact and loading rate increased by 16% and 22%, indicating good impact reduction, and at pre swing, it increased the initial flexion angle and angular velocity by 13% and 15%, respectively, enhancing the swing phase.

Buckling analysis of mechanical structures is essential to insure stability under loading .Critical load of buckling refer to the maximum load can be withstood without losing of stability and avoid a catastrophic damage due to the collapse of columns .Improving of mechanical properties spatially those related with elastic behaviors of materials can lead to improving buckling since it can be raised the value of critical load. Nanotechnology is one of the modern methods which makes significant effects on the mechanical properties of materials. In the field of composite materials this technology leads to valuable improvements for the favorite properties. In this regard Nano composite materials are paid a spatial attention in research for the last decade. The main aim of the present work is to investigate the effect of Nano carbon weight fraction on buckling of the composite plate. Five samples of Nano composite plates were prepared and fabricated for experimental investigations .The plate samples are combined of woven reinforcement fiber and polyester matrix with Carbon .The weight fraction of Nano additives are 0 %, 0.5%, 1%, ,1.5 and 2%, of resin materials weight. To provide homogenous composite an ultrasonic homogenizer is utilized. The experimental work include buckling test for different Nano plates samples with simply supported at two ends and free at the other .Finite Element analysis was achieved via ANSYS R15.0 with proper elements ,meshing ,boundary condition and static analysis .It is found that increasing of Nano carbon weight ratio tends to increase critical load of buckling ,the maximum buckling load is at 2% wt ratio and the experimental results shows fair validation for the numerical analysis where the maximum error dos not exceeded 15% .

In this paper an attempt to provide a single degree of freedom lumped model for fluid structure interaction (FSI) dynamical analysis will be presented. The model can be used to clarify some important concept in the FSI dynamics such as the added mass, added stiffness, added damping, wave coupling ,influence mass coefficient and critical fluid depth . The numerical results of the model show that the natural frequency decrease with the increasing of many parameters related to the structure and the fluid .It is found that the interaction phenomena can become weak or strong depending on the depth of the containing fluid .The damped and un damped free response are plotted in time domain and phase plane for different model parameters It is found that the vibration free response is still sinusoidal for weak FSI coupling ,however for strong coupling it behaves as modulated periodic response .To justify some of the theoretical aspects such as; the effects of the fluid density and the interact shape on the natural frequency an experiment was conducted .The results of the experiment shows a good agreement with the theory where the error is not exceeded 7%.

In this work it had been focused on the possibility of replacement of steel spring in suspension system by fiber reinforced polymer composite that is responsible for light weight of spring which leads to reduces the weight of vehicle and improve fuel efficiency. This type of spring used in motor cycles, light weight vehicle.  The design will be simulated by ANSYS workbench. Then, E-Glass fiber has been used to fabricate helical compression spring of 40%   fiber volume fraction of glass. with polyester resin. The deflection of glass reinforced composite spring is more than steel spring but within permissible limit. weight of composite spring is reduced by 57% than of steel.

Pressure vessels are the heart of plants and oil refineries stations. In many engineering applications such vessels can be subjected to periodic loading either internally due to the charging and discharging process or externally due to the excitation from other nearby components such as pumps, compressors or from seismic. So that in spite of a good design according static assumption it may be critical in dynamics. In this work a horizontal pressure vessel with accessories subjected to liquefied petroleum gas pressure LPG is considered. Three models of different head types are investigated herein namely; Deep torispherical, Elliptical 2:1 and Hemispherical. The design and material selections are chosen as per ASME. For practical service many accessories are attached to the vessel such as manhole, supports, inlet and outlet opining. Finite Element method via ANSYS R18.2 is introduced for the numerical analysis. The fatigue life in case of fully reversed cyclic loading are estimated and located. Vibration characteristics such as mode shapes and natural frequencies for the lowest five modes are evaluated and compared. It is found that the fatigue life can be increased as higher as 180% for hemi-spherical head as compared with deep torispherical head pressure vessel and the lowest four natural frequencies are nearly identical for all models, however significant change observed in the fifth natural frequency.