The fuel and cost efficiency in automotive industry is related to the designing of light-weight vehicle components. Main aim of this paper is to show effectiveness of two new optimization algorithms in solving structural design optimization problems. The gravitational search algorithm (GSA) and charged system search algorithm (CSS) are applied to the optimum design of a vehicle component. The results show that both GSA and CSS have a better search capability than the genetic algorithms to find optimum solutions.

This study develops and characterizes the distinctive mechanical features of a stainless-steel metal stent with a tailored structure. A high-precision femtosecond laser was used to micromachine a stent with re-entrant hexagonal (auxetic) cell geometry. We then characterized its mechanical behavior under various mechanical loadings using in vitro experiments and through finite element analysis. The stent properties, such as the higher capability of the stent to bear upon bending, exceptional advantage at elevated levels of twisting angles, and proper buckling, all ensured a preserved opening to maintain the blood flow. The outcomes of this preliminary study present a potential design for a stent with improved physiologically relevant mechanical conditions such as longitudinal contraction, radial strength, and migration of the stent.

This paper deals with a new product design framework for the optimal structural design applications. The proposed approach called hybrid charged system search (CSS) and Nelder-Mead algorithm (HCSSNM) offers significant improvements in performance over existing methods in the field of computer-aided design optimisation. The HCSSNM based on the CSS and Nelder-Mead algorithm is used for optimisation of a vehicle suspension arm which is critically important for the vehicle safety. As observed in the results, the HCSSNM can be used effectively to reduce the mass of the vehicle components while maintaining its fatigue durability.

The objective of this study was to evaluate the potential of a survival prediction method for the assessment of ceramic dental restorations. For this purpose, fast-fracture and fatigue reliabilities for 2 bilayer (metal ceramic alloy core veneered with fluorapatite leucite glass-ceramic, d.Sign/d.Sign-67, by Ivoclar; glass-infiltrated alumina core veneered with feldspathic porcelain, VM7/In-Ceram Alumina, by Vita) and 3 monolithic (leucite-reinforced glass-ceramic, Empress, and ProCAD, by Ivoclar; lithium-disilicate glass-ceramic, Empress 2, by Ivoclar) single posterior crown restorations were predicted, and fatigue predictions were compared with the long-term clinical data presented in the literature. Both perfectly bonded and completely debonded cases were analyzed for evaluation of the influence of the adhesive/restoration bonding quality on estimations. Material constants and stress distributions required for predictions were calculated from biaxial tests and finite element analysis, respectively. Based on the predictions, In-Ceram Alumina presents the best fast-fracture resistance, and ProCAD presents a comparable resistance for perfect bonding; however, ProCAD shows a significant reduction of resistance in case of complete debonding. Nevertheless, it is still better than Empress and comparable with Empress 2. In-Ceram Alumina and d.Sign have the highest long-term reliability, with almost 100% survivability even after 10 years. When compared with clinical failure rates reported in the literature, predictions show a promising match with clinical data, and this indicates the soundness of the settings used in the proposed predictions.

Work-related musculoskeletal disorders are one of the main problems reducing the life quality of workers. Occupational exoskeletons are one of the most promising solutions for solving this issue. In this study, an innovative and passive upper-extremity exoskeleton design was presented and tested by measuring ten different muscle activities for two tasks: Task 1, for over-the-head tool handling, and Task 2, for completely stretched forearm tool handling. The special optimized switch mechanism design allowed for free motion when it was not active, which provided design advantages in comparison to the currently available designs. The muscle activity levels were measured via EMG for both tasks and the results were compared and evaluated with and without the exoskeleton on the human body. It was shown that the muscle activity for Task 1 was reduced by 55% for the middle deltoid, 37% for the posterior deltoid, and 27% for the anterior deltoid muscles, in comparison to no exoskeleton for Task 1. For Task 2, the muscle activity was reduced by 48% for the middle deltoid, 20% for the posterior deltoid, and 38% for the anterior deltoid. The exoskeleton presented in this study is an efficient design that significantly increases shoulder comfort, especially in working conditions, without bringing an additional metabolic cost for the secondary muscles.