أمير عبد المنعم كاظم الزريجاوي

In this paper, an improvement is suggested to increase the fatigue life of the isotropic materials combined from glass short fibers and polyester resin materials by adding the reinforcements of powder materials to increase the fatigue strength. Two types of powder materials were investigated, carbon and glass with and without powder reinforcement. The investigation was conducted experimentally and numerically. The experimental program covers the manufacturing the tensile and fatigue samples and evaluate the mechanical properties and the fatigue strength using the different volume fractions and types of powders. The experimental results are compared with those obtained numerically using the finite element technique adopting Ansys program. The comparison has shown a good agreement between the two techniques with a maximum discrepancy of (9.46%). Also, the results indicate that the reinforcement of the composite material by powder materials increase the fatigue limit. Also, the improvement of fatigue life by using the carbon powder is better than that obtained by using the glass powder.

In this work an attempt is made to derive suitable models to investigate the effect of the joints constrained on human gait due to wearing bracing devices at lower limbs. Linkages concept are used to model the leg segments and evaluate GRF and friction force. Three models for normal, AFO and KAFO are presented. The presented models are semi analytic since some input data are needed to be evaluated experimentally. In this regard the joint angles are evaluated from video analysis of individual walking on Treadmill. KINOVEA program is used to track the joints angles for the stance phase of gait cycle, and the MATLAB program is used to estimate the angular displacement as a function of time. To validate the results some experiments on force plate were conducted for the three mentioned cases. The results showed good agreements and that the suggested models are succeeded for describing the human gait parameters for normal and abnormal gait.