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There are millions of persons in this world have been suffered from land mines or other accidental events which have caused amputations. The human body feet provide stability and balance when standing and moving. Amputation of a foot highly decrease the amputee’s ability to practice common activities such as walking. The main target of a prostheses of any kind is to improve or return function to a physically disabled person. Although, the rapid developing of alternative prostheses technology, unfortunately, it is still a far from inquiring quite functional prosthetic limb replacement. The present study was focused on design and manufacturing of a two degree of freedom ankle rotation, plantar flexion- dorsiflexion in sagittal plane and inversion - eversion in frontal plain so as to mimic the normal human gait and also to reduce the pain and stress in the residual limb. Most ankle parts were formed from aluminum alloy and assembled to a carbon fiber foot laminated foot. The gait analysis was performed by the amputee user case study for both his prosthetic foot and the designed foot at the same optional ground surface conditions. The user foot angles responses were: eversion 2.60, inversion 2.60, plantar 8.70, dorsi 5.30, in contrast, the designed foot angles were: eversion 9.50, inversion 9.80, plantar 10.20, dorsi 10.40. The achieved designed maximum rolling in frontal plane was 100 inversion- eversion angle and the maximum rolling in sagittal plane were 120, 180 for plantar and dorsi flexion angle respectively.

In the present study, the effect of circular cutout in the skin of composite aircraft wing on the natural frequencies was studied by finite element method using ANSYS software version 11. The case which was studied is the presence of circular cutout in the skin of the wing through its thickness. The parameters which were studied are the cutout ratio, the location of cutout along the wing span, the location of the cutout along the wing width and the number of the damaged panels. The results showed that the presence of cutout caused a small decreasing in the natural frequencies. The increasing in the cutout ratio and the number of damaged panels caused a small decrease in the natural frequencies. The variation in the location of the cutout along the wing span and the wing width caused very small effect on the natural frequencies.