No abstract

Compliant mechanisms’ design aims to create a larger workspace and simple structural shapes because these mechanical systems usually have small dimensions, reduced friction, and less bending. From that request, we designed optimal bridge-type compliant mechanism flexure hinges with a high magnification ratio, low stress by using a flexure joint, and especially no friction and no bending. This joint was designed with optimal dimensions for the studied mechanism by using the method of grey relational analysis (GRA), which is based on the Taguchi method (TM), and finite element analysis (FEA). Grey relational grade (GRG) has been estimated by an artificial neural network (ANN). The optimal values were in good agreement with the predicted value of the Taguchi method and regression analysis. The finite element analysis, signal-to-noise analysis, surface plot, and analysis of variance demonstrated that the design dimensions significantly affected the equivalent stress and displacement. The optimal values of displacement were also verified by the experiment. The outcomes were in good agreement with a deviation lower than 6%. Specifically, the displacement amplification ratio was obtained as 65.36 times compared with initial design.

It is argued that ports are playing a crucial role in developing nations’ economy. Still, solutions to improving port service quality (PSQ) to boost ports’ competitive capacity is questionable. Hence, this study aims to investigate port service quality (PSQ) by using integration of the extension Fuzzy Analytic Hierarchy Process and Importance-Performance Analysis (IPA) from port users’ perspectives. From the relevant literature and expert interview, the hierarchical structure of PSQ embracing six dimensions with 29 criteria was first established. To test the research model, the Dong Nai port joint stock company (DNPC) and their port-service users were empirically investigated. It is found that: (1) the importance degree of dimensions is ranked as follow: empathy (21.07%), tangibles (20.15%), assurance (15.97%), reliability (15.54%), responsiveness (12.53%), diversity (14.74%); (2) for criteria of PSQ, top five criteria concerned by shipping companies and ocean freight forwarders comprise: "proactive provision of vessel schedules", "cargo handling facilities and equipment", "detailed schedule", "accuracy and consistency of schedules", and "geographical location"; (3) there are four service attributes (SAs) needing to prioritize for improvement, including "perfect transportation of cargos", "ability in dealing with cargo damage", "willingness in helping customers", "provision of special cargo-related services". The practical policy is that port authorities should transfer the limited resources from SAs in Quadrant IV to Quadrant II to enhance the PSQ.

The compliant mechanism always requests high displacement amplification ratio and high vibration frequency. Therefore, this paper optimized design parameters to obtain the maximum value of the first frequency modal shape using the Taguchi method. First, the model was designed by Solidworks. Second, effect design parameters on the first frequency modal shape were analyzed via ANSYS Workbench 18.0, and the final the maximum value of the first frequency modal was obtained by the Taguchi method. The simulation results revealed that the thickness and width of flexure hinge has a significant effect on the first frequency modal. The S/N analysis results demonstrated that the thickness of the flexure hinge has a significant affect next to the width of the flexure hinge, inline angle between two flexure hinges, input body length, and the fillet radius of the flexure hinge. The ANOVA analysis results identified that the contribution percentage of design parameters and fillet radius of the flexure hinge have a significant effect on the first frequency modal. The R-square was obtained at 99.84%, and the maximum value of the first frequency modal was obtained at 821.8267 Hz.