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In this study, a simplified approach that can be used for the selection of the design parameters of carbon and glass fiber reinforced composite beams is presented. Important design parameters including fiber angle orientation, laminate thickness, materials of construction, cross-sectional shape, and mass are considered. To allow for the integrated selection of these parameters, structural indices and efficiency metrics are developed and plotted in design charts. As the design parameters depend on mode of loading, normalized structural metrics are defined for axial, bending, torsional, and combined bending-torsional loading conditions. The design charts provide designers with an accurate and efficient approach for the determination of stiffness parameters and mass of laminated composite beams. Using the design charts, designers can readily determine optimum fiber direction, number of layers in a laminate, cross-sectional shape, and materials that will provide the desired mass and stiffness. The laminated composite beams were also analyzed through a detailed finite element analysis study. Three-dimensional solid elements were used for the finite element modelling of the beams. To confirm design accuracy, numerical results were compared with close-form solutions and results obtained from the design charts. To show the effectiveness of the design charts, the simplified method was utilized for increasing the bending and torsional stiffness of a laminated composite robotic arm. The results show that the proposed approach can be used to accurately and efficiently analyze composite beams that fall within the boundaries of the design charts.

T-joint connections are commonly encountered in many machine components and load carrying members. The T-joint connections can be fabricated using traditional cutting (machine or flame) or by laser cutting techniques. The present study investigates the feasibility of using laser cutting to produce welded square hollow-section T-joints with similar or higher fatigue strengths than their conventional mechanical cut counterparts. A total of 21 full-scale T-joint samples, typical of those found in the agricultural industry, were included in this study. Nineteen of these samples were examined with the intention of forming a fatigue crack of approximately 3.8 cm (1.5 in.es) in length, and two samples with strain gauges attached for strain measurements. The experimental results of the full-scale T-joints subjected to cyclic loads showed that the fatigue strength of the samples that were manufactured with laser cutting were higher than those fabricated with mechanical cutting. A finite element analysis (FEA) of the T-joints was also performed, and the FEA results were verified with the experimental strain measurements.

A major challenge in developing next generation intelligent mechatronic systems lies in the complexity of integrating an enormous number of requirements including high performance, multi-functionality, low cost, and complicated physical structures. Hybridization is a promising approach for developing next generation intelligent mechatronic systems. In this paper, a hybrid actuation system is developed where a controllable servomotor and an uncontrollable constant velocity motor are integrated to form a closed-loop two degrees of freedom hybrid mechanism. An experimental prototype of the hybrid actuation system is built. To fulfill a desired trajectory tracking, a sophisticated control system is developed for controlling the hybrid actuation system. After that, experimental studies are conducted using the proposed control algorithm. Experimental results demonstrate the controllability of the hybrid actuation system and the effectiveness of the designed control algorithm. Finally, some issues for improving the tracking performance are discussed in this paper.