This paper proposes an approach to evaluate the performance of robot manipulator from the view of energy analysis. Based on the dynamics analysis of the manipulator, the Energy Distribution Index （EDI） is defined to depict the energy increment contribution of its subsystem to the whole manipulator. EDI is applied to the evaluation of the buffeting capability of the manipulator working under unpredictable and heavy external loads. A series of buffering indices, the Static Buffering Index （SBI）, Kineto-Static Buffering Index （KBI）, Dynamic Buffering Index （DBI）, and Global Buffering Index （GBI） are proposed to evaluate the buffering capability under different conditions. In order to acquire higher calculation accuracy, the general stiffness mapping of manipulators considering the actuator stiffness, inertia of the manipulator, damping, as well as elasticity of linkages is developed. Three different robot manipulators are studied as evaluation cases, in which the buffering structures are mechanism with variable topology, linear springs, and the elasticity of linkages respectively. The case studies show that the indices based on energy analysis have the advantage of coordinate free and are effective for buffering capability evaluation.
To gain a better understanding about texture evolution during rolling process of AZ31 alloy, polycrystalline plasticity model was implemented into the explicit FE package, ABAQUS/Explicit by writing a user subroutine VUMAT. For each individual grain in the polycrystalline aggregate, the rate dependent model was adopted to calculate the plastic shear strain increment in combination with the Voce hardening law to describe the hardening response, the lattice reorientation caused by slip and twinning were calculated separately due to their different mechanisms. The elasto-plastic self consistent （EPSC） model was employed to relate the response of individual grain to the response of the polycrystalline aggregate. Rolling processes of AZ31 sheet and as-cast AZ31 alloy were simulated respectively. The predicted texture distributions are in aualitative a^reement with experimental results.
GLARE （glass fibre/epoxy reinforced aluminum laminate） is a member of the fiber metal laminate （FML） family, and is built up of alternating metal and fiber layers. About 500 m2 GLARE is employed in each Airbus A380 because of the superior mechanical properties over the monolithic Muminum alloys, such as weight reduction, improved damage tolerance and higher ultimate tensile strength. Many tons of new GLARE scraps have been accumulated during the Airbus A380 manufacturing. Moreover, with the increasing plane orders of Airbus A380, more and more end-of-life （EOL） GLARE scrap will be generated after retire of planes within forty years. Thermal processing is a potential method for the material recycling and re-use from GLARE with the aim of environmental protection and economic benefits. The current study indicatdes that thermal delamination is a crucial pre-treatment step for the GLARE recycling. The decomposition behavior of the epoxy resins at elevated temperatures was investigated by using the simultaneous thermal analysis, thermogravimetry analysis （TGA） and differential scanning calorimetry （DSC）. Based on the thermal analysis results, GLARE thermal delamination experiments at refined temperatures were carried out to optimize the treatment temperature and holding time.
Recycling of aluminum alloy scrap obtained from delaminated fibre metal laminates （FMLs） was studied through high temperature refining in the presence of a salt flux. The aluminum alloy scrap contains approximately mass fraction w（Cu） = 4.4%, w（Mg） = 1.1% and w（Mn） = 0.6% （2024 aluminum alloy）. The main objective of this research is to obtain a high metal yield, while maintaining its original alloy compositions. The work focuses on the metal yield and quality of recycled A1 alloy under different refining conditions. The NaCI-KC1 salt system was selected as the major components of flux in the A1 alloy recycling. Two different flux compositions were employed at NaC1 to KC1 mass ratios of 44：56 and 70：30 respectively, based on either the euteetic composition, or the European preference. Different additives were introduced into the NaCI-KC1 system to study the effect of flux component on recycling result. Although burning and oxidation loss of the alloying elements during re-melting and refining take place as the drawbacks of conventional refining process, the problems can be solved to a large extent by using an appropriate salt flux. Experimental results indicate that Mg in the alloy gets lost when adding cryolite in the NaCI-KC1 salt system, though the metal yield can reach as high as 98%. However, by adding w（MgF2） = 5% into the NaCI-KC1 salt system （instead of using cryolite） all alloying elements were well controlled to its original composition with a metal yield of almost 98%.
A non-local dislocation density based crystal plasticity model, which takes account of the microstrncture inhomogeneity, was used to investigate the micro-bending of metallic crystalline foils. In this model, both statistically stored dislocations （SSDs） and geometrically necessary dislocations （GNDs） are taken as the internal state variables. The strain gradient hardening in micro-bending of single-grained metal foils was predicted by evolution of GNDs. The predicted results were compared with the micro-hardness distribution of the previous micro-bending experiments of CuZn37 a-brass foils with coarse grains and fine grains. Comparison of the simulated dislocation densities distribution of SSDs and GNDs with the experimental results shows that different micro-hardness distribution patterns of the coarse and fine grain foils can be attributed to the corresponding SSDs and GNDs distributions. The present model provides a physical insight into the deformation mechanism and dislocation densities evolution of the micro-bending process.
Fecal incontinence is an unresolved problem, which has a serious effect on patients, both physically and psychologically. For patients with severe symptoms, treatment with an artificial anal sphincter could be a potential option to restore continence. Currently, the Acticon Neosphincter is the only device certified by the US Food and Drug Administration. In this paper, the clinical safety and efficacy of the Acticon Neosphincter are evaluated and discussed. Furthermore, some other key studies on artificial anal sphincters are presented and summarized. In particular, this paper highlights that the crucial problem in this technology is to maintain long-term biomechanical compatibility be- tween implants and surrounding tissues. Compatibility is affected by changes in both the morphology and mechanical properties of the tissues surrounding the implants. A new approach for enhancing the long-term biomechanical compatibility of implantable artificial sphincters is proposed based on the use of smart materials.
Feature extraction from vibration signals has been investigated extensively over the past decades as a key issue in machine condition monitoring and fault diagnosis.Most existing methods,however,assume a linear model of the underlying dynamics.In this study,the feasibility of devoting nonlinear dynamic parameters to characterizing bearing vibrations is studied.Firstly,fuzzy sample entropy (FSampEn) is formulated by defining a fuzzy membership function with clear physical meaning.Secondly,inspired by the multiscale sample entropy (multiscale SampEn) which is originally proposed to quantify the complexity of physiological time series,we placed approximate entropy (ApEn),fuzzy approximate entropy (FApEn) and the proposed FSampEn into the same multiscale framework.This led to the developments of multiscale ApEn,multiscale FApEn and multiscale FSampEn.Finally,all four multiscale entropies along with their single-scale counterparts were employed to extract discriminating features from bearing vibration signals,and their classification performance was evaluated using support vector machines (SVMs).Experimental results demonstrated that all four multiscale entropies outperformed single-scale ones,whilst multiscale FSampEn was superior to other multiscale methods,especially when analyzed signals were contaminated by heavy noise.Comparisons with statistical features in time domain also support the use of multiscale FSampEn.
