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The purpose of this paper is to examine the mechanical behaviour of additively manufactured Ti-6Al-4V under cyclic loading. Using as-built selective laser melting (SLM) Ti-6Al-4V in engineering applications requires a detailed understanding of its elastoplastic behaviour. This preliminary study intends to create a better understanding on the cyclic plasticity phenomena exhibited by this material under symmetric and asymmetric strain-controlled cyclic loading.

This paper investigates experimentally the cyclic elastoplastic behaviour of as-built SLM Ti-6Al-4V under symmetric and asymmetric strain-controlled loading histories and compares it to that of wrought Ti-6Al-4V. Moreover, a plasticity model has been customised to simulate effectively the mechanical behaviour of the as-built SLM Ti-6Al-4V. This model is formulated to account for the SLM Ti-6Al-4V-specific characteristics, under the strain-controlled experiments.

The elastoplastic behaviour of the as-built SLM Ti-6Al-4V has been compared to that of the wrought material, enabling characterisation of the cyclic transient phenomena under symmetric and asymmetric strain-controlled loadings. The test results have identified a difference in the strain-controlled cyclic phenomena in the as-build SLM Ti-6Al-4V when compared to its wrought counterpart, because of a difference in their microstructure. The plasticity model offers accurate simulation of the observed experimental behaviour in the SLM material.

Further investigation through a more extensive test campaign involving a wider set of strain-controlled loading cases, including multiaxial (biaxial) histories, is required for a more complete characterisation of the material performance.

The present investigation offers an advancement in the knowledge of cyclic transient effects exhibited by a typical α’ martensite SLM Ti-6Al-4V under symmetric and asymmetric strain-controlled tests. The research data and findings reported are among the very few reported so far in the literature.

The symmetrical valve is usually used in the hydraulic servo control system to control the asymmetrical cylinder, but this system’s structure involves asymmetry, and so its dynamic characteristics are asymmetrical, which causes issues in the control system of symmetric response. The purpose of this paper is to achieve the aim of symmetric control.

In this paper, the authors proposed a method that combined wavelet neural network (WNN) and model reference adaptive control. The reference model determined the dynamic response that the system was expected to achieve, and the WNN adaptive control made the system follow the reference model to achieve the purpose of symmetric control.

The experimental results show that the method can achieve a more accurate symmetric control and position control compared with the solutions via the classical PID control.

The proposed combination of the WNN and the reference model can effectively compensate for the asymmetry of dynamic response of the asymmetric cylinder in forward and return directions, which can be extended to deal with other classes of applications.

This study presents the improvements of the multicomponent Armstrong–Frederick model with multiplier (MAFM) performance through a numerical optimisation methodology available in a commercial software. Moreover, this study explores the application of a multiobjective optimisation technique for the determination of the parameters of the constitutive models using uniaxial experimental data gathered from aluminium alloy 7075-T6 specimens. This approach aims to improve the overall accuracy of stress–strain response, for not only symmetric strain-controlled loading but also asymmetrically strain- and stress-controlled loading.

Experimental data from stress- and strain-controlled symmetric and asymmetric cyclic loadings have been used for this purpose. The analysis of the influence of the parameters on simulation accuracy has led to an adjustment scheme that can be used for focused optimisation of the MAFM model performance. The method was successfully used to provide a better understanding of the influence of each model parameter on the overall simulation accuracy.

The optimisation identified an important issue associated with competing ratcheting and mean stress relaxation objectives, highlighting the issues with arriving at a parameter set that can simulate ratcheting and mean stress relaxation for load cases not reaching at complete relaxation.

The study uses a strain-life fatigue application to demonstrate the importance of incorporating a technique such as the presented multiobjective optimisation method to arrive at robust parameters capable of accurately simulating a variety of transient cyclic phenomena.

The proposed methodology improves the accuracy of cyclic plasticity phenomena and strain-life fatigue simulations for engineering applications. This study is considered a valuable contribution for the engineering community, as it can act as starting point for further exploration of the benefits that can be obtained through material parameter optimisation methodologies for models of the MAFM class.

The search of the optimal economic design of the Bayesian adaptive control charts for finite production runs can be a long and tedious procedure due to the intrinsic structure of the optimization problem, which requires a dynamic programming approach to select the best decision at each sampling epoch during the production horizon of the process. This paper aims to propose a new efficient procedure implementing a genetic algorithm neighbourhood search scheme embedded within the dynamic programming procedure with the aim of reducing the computational burden and achieving significant cost savings in the chart implementation.

The efficiency of the developed procedure has been verified through a comparison with another existing exhaustive approach working exclusively on one‐sided X¯ Bayesian control charts; then, it has been extended to the design of two‐sided Bayesian control charts.

The proposed procedure implementing the genetic algorithm neighbourhood search is very fast and efficient in detecting optimal solutions: it allows significant quality control cost savings to be achieved during the Bayesian charts implementation thanks to the possibility of investigating larger spaces of decisions than the existing optimization procedures.

With reference to discrete part manufacturing, where the assumption of finite production runs is often realistic, the design and implementation of adaptive Bayesian control charts by means of the proposed procedure allows significant cost savings to be achieved with respect to the fixed parameters Shewhart charts.

The exhaustive optimization procedure cannot be executed in a reasonable computational time when the space of decisions to select Bayesian chart design parameters significantly enlarges, which is the case of two‐sided control charts. The paper documents the proposed procedure which overcomes this problem and allows the two‐sided Bayesian chart to be designed and proposed as an efficient means to monitor short production runs.

The purpose of this paper is to develop an extensive economic production quantity (EPQ) model on the basis of previous research. Considering an imperfect three‐state production process, this paper makes contributions to an integrated model combining conceptions of quality loss and design of control chart based on EPQ model. The objective is to minimize the total production cost with the determination of EPQ and design parameters of control chart subjected to quality loss and other process costs.

In this paper, imperfect process is defined as a three‐state process, and the quality cost corresponding to each state contributes to the eventual total expected cost formulation. Control chart is used to monitor the shift from the target value within whole process and its control limits are set to be related to the quality cost.

The proposed integrated model conforms more closely to the real situation of production process considering the process shift as a random variable.

Numerical computation and sensitivity analysis through a case study are presented to demonstrate the applications of the model.

Few research efforts investigate an integrated model considering EPQ, control chart and quality loss simultaneously. In particular, compared with the former researches, the process shift, due to which the quality cost incurs, is considered as a random variable in this paper.

This paper aims to develop a pose/force coordination method for a redundant dual-arm robot to achieve a symmetric coordination task.

A novel control strategy of dual-arm coordination is proposed that associates pose coordination with force coordination. The spatial in-parallel spring and damping model is built to regulate the relative pose error of two end-effectors in real time, and force coordination factor is introduced to realize the dynamic distribution of loadings to limit the object’s internal force in real time.

The proposed method was verified on a real dual-arm robot platform. The symmetric coordination task is performed and the experiment results show that a good behavior on the regulation of the relative pose errors between two arms to achieve the object’s trajectory tracking, and the distribution of the two end-effectors’ loadings to limit the object’s internal force.

The benefits of the proposed method are to improve the object’s tracking performance and avoid the object damage during the symmetric coordination task.

The purpose of this paper is to evaluate the physiotherapeutic benefits of bilateral symmetric training (BST) for stroke survivors affected by hemiparesis.

Other studies have investigated symmetric physiotherapy. A key difficulty in previous work is in maintaining mirror-imaged trajectories between the affected and less-affected limbs. This obstacle was overcome in this work by using a two-armed robotic exoskeleton to enforce symmetry. In total, 15 subjects, > 6 months post stroke were, randomly assigned to bilateral symmetric robotic training, unilateral robotic training, and standard physical therapy.

After 12 training sessions (90 minutes/session), the bilateral training group had the greatest intensity of movement training. They also had the greatest improvement in range of motion at the shoulder. The unilateral training group showed the greatest reduction in spasticity.

The rationale for symmetric physiotherapy is that it might promote connections from the undamaged brain hemisphere. The robot generated copious amounts of detailed kinematic data. Even though these data provided insights into the human to machine interface using different training modalities, it proved difficult to draw neurological conclusions. It is recommended that future research along these lines should include measures of neurophysiological change and/or changes in neurological activity.

This research suggests that the advantage of bilateral symmetric movement over other modalities is slight, and that robotic training has comparable results with standard care. If BST is used, care is potentially needed to avoid exacerbation of spasticity. Finally, this research includes a novel quantitative approach for evaluating robotic training.

This study is of value to therapeutic researchers interested in new physiotherapy techniques, roboticists interested in developing rehabilitation devices, or for rehabilitation game designers interested in using virtual reality.

This study aims to investigate the relationship between trust and performance in international joint ventures (IJVs) with the moderating effects of the structural mechanisms from transaction cost approach.

Using web-survey, data are collected from 89 IJVs of Northern European firms in Asia, Europe and America. Empirical data are analyzed with structural equation modeling and estimates moderating effects of symmetric dependence, symmetric equity share and resource complementarity.

The findings offer some interesting insights for transaction cost and the social exchange theory. This study demonstrates that a symmetric equity share between IJV partners does not moderate the trust–performance relationship, while a symmetric dependence and resource complementarity between partners effect positively. Therefore, trust takes on greater importance in enhancing IJV performance under symmetric dependence and resource complementarity and symmetric equity share between IJV partners deprecates the importance of equity distribution.

A symmetric dependence prevents the deceit from either partner in trusting relationships. Further, a trustful relationship enhances IJV performance regardless of the equity share in IJVs. IJVs with asymmetric equity share can also be successful, provided that IJV partners develop inter-partner trust.

The extant research has not examined how the trust–performance relationship is contingent on structural mechanisms of IJVs that transaction cost economics deem necessary to prevent opportunistic behavior. Three structural mechanisms of symmetric dependence, symmetric equity share and resource complementarity moderate the trust–performance relationship in IJVs.

This paper aims to examine the design and control of a symmetric multilevel inverter (MLI) using grey wolf optimization and differential evolution algorithms.

The optimal modulation index along with the switching angles are calculated for an 11 level inverter. Harmonics are used to estimate the quality of output voltage and measuring the improvement of the power quality.

The simulation is carried out in MATLAB/Simulink for 11 levels of symmetric MLI and compared with the conventional inverter design. A solar photovoltaic array-based experimental setup is considered to provide the input for symmetric MLI. Field Programmable Gate Array (FPGA) based controller is used to provide the switching pulses for the inverter switches.

Attempted to develop a system with different optimization techniques.

A low-cost but credible method of low-subsonic flutter analysis based on ground vibration test (GVT) results is presented. The purpose of this paper is a comparison of two methods of immediate flutter problem solution: JG2 – low cost software based on the strip theory in aerodynamics (STA) and V-g method of the flutter problem solution and ZAERO I commercial software with doublet lattice method (DLM) aerodynamic model and G method of the flutter problem solution. In both cases, the same sets of measured normal modes are used.

Before flutter computation, resonant modes are supplied by some non-measurable but existing modes and processed using the author’s own procedure. For flutter computation, the modes are normalized using the aircraft mass model. The measured mode orthogonalization is possible. The flutter calculation made by means of both methods are performed for the MP-02 Czajka UL aircraft and the Virus SW 121 aircraft of LSA category.

In most cases, both compared flutter computation results are similar, especially in the case of high aspect wing flutter. The Czajka T-tail flutter analysis using JG2 software is more conservative than the one made by ZAERO, especially in the case of rudder flutter. The differences can be reduced if the proposed rudder effectiveness coefficients are introduced.

The low-cost methods are attractive for flutter analysis of UL and light aircraft. The paper presents the scope of the low-cost JG2 method and its limitations.

In comparison with other works, the measured generalized masses are not used. Additionally, the rudder effectiveness reduction was implemented into the STA. However, Niedbal (1997) introduced corrections of control surface hinge moments, but the present work contains results in comparison with the outcome obtained by means of the more credible software.