Abstract ：

针对增材制件内部缺陷检测，提出一种内部缺陷埋藏深度的定量检测方法。对用激光超声无损检测技术接收到的信号采用小波包分解技术进行分离并提取信号中的超声纵波，解决了超声表面波和纵波耦合影响时域特征提取的问题。根据检测过程中经过缺陷的纵波声程的变化，实现了精锻试块内部缺陷埋藏深度的定量检测，检测结果的相对误差为1.81%。在原检测方法的基础上增加异常点滤除算法，并应用于增材制件内部缺陷的检测，检测结果的相对误差为1.76%。

Keyword ：

定量检测 激光超声检测 埋藏深度 内部缺陷 增材制造

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Abstract ：

A quantitative detection method for the buried depth of internal defects was proposed for the detection of internal defects in additive manufacturing parts. The wavelet packet decomposition technology was used to separate and extract the ultrasonic longitudinal waves in the signals received by the laser ultrasonic nondestructive testing technology, which solvesd the problems that the coupling of ultrasonic surface wave and longitudinal wave affected the time-domain feature extraction. According to the changes of the longitudinal wave sound path of the defects during the detection processes, the quantitative detection of the buried depth of the internal defects in the precision forging samples was realized, and the relative error of the tests is 1.81%. An abnormal point filtering algorithm was added on the basis of the original detection method, and it was applied to the detection of internal defects of manufacturing additive parts with the relative error of detection of 1.76%. © 2022, China Mechanical Engineering Magazine Office. All right reserved.

Keyword ：

3D printers Additives Crack detection Feature extraction Nondestructive examination Surface waves Time domain analysis Ultrasonic testing Wavelet decomposition

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Abstract ：

Although the traditional graphite anode materials have stable cycle performance, it has low capacity which limits its energy density. Therefore, it is urgent to prepare new anode materials. During the past decades, the metal oxides are considered as the most promising anode materials due to their high specific capacity and energy density. However, the metal oxide anode suffers from poor cycling stability, which is caused by the unstable structure and poor electrode/electrolyte interphase. Herein, we design the stannic oxide@C composites via hydrothermal reaction method and used as anode materials for the lithium-ion batteries. Due to the improved charge transfer kinetics at the electrode/electrolyte interphase, the as-prepared stannic oxide@C composites show high specific capacity and stable cycling performance at the high current densities.

Keyword ：

Charge transfer Diffusion Interphase Kinetics Lithium-ion

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Abstract ：

Reducing the quality fluctuation and real-time effective identification of error source are the key issues in achieving quality control of manufacturing process stability. Therefore, this paper proposes a dynamic multi-gradient decoupling search method based on entropy fluctuation. An error transfer network model of brittle fluctuation and a multi-gradient quality fluctuation evaluation system are constructed. A real-time search decoupling is performed on the path of the error transfer by combining the characteristics of the small world network. This method can trace back to the key error source that affect the current quality state fluctuations and realize dynamic and effective control of quality fluctuations. Finally, the effectiveness of the model proposed is validated through the forging process. Key words - Brittle quality fluctuation; Multi-gradient decoupling; Entropy space search; Dynamic quality control © 2019 IEEE.

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Traditional multi-objective evolutionary algorithms (MOEAs) adopt selection and reproduction operators to find approximate solutions for multi-objective optimization problems (MOPs). The Pareto-dominancebased method is an important branch of MOEA research which exploits dominance relations information. To use dominance relations information more efficiently, this paper proposes an individualized instruction mechanism combined with the non-dominated sorting concept and the teaching-learning process of teaching-learning-based optimization (TLBO). This algorithm, with its individualized instruction mechanism (INM-TLBO), places greater emphasis on the guiding role of the non-dominated solution. INM-TLBO designates specific teachers or interactive objects to help learners improve in the individualized teaching learning process and adopts an external archive to preserve the best solution found. In addition, the INM-TLBO needs only generic control parameters as input, such as population size, an epsilon value for the external archive, and a stop criterion (maximal generation or function evaluation). The performance of INM-TLBO was evaluated on three test problem sets, including twelve extensively used unconstrained test problems, six truly disconnected test problems, and ten complex continuous unconstrained optimization test problems originally proposed for the Congress on Evolutionary Computation 2009 (CEC 2009) competition. The numerical results are compared with those of other state-of-the-art algorithms and show that INM-TLBO has good convergence and high robustness on these test problems. (C) 2017 Elsevier B.V. All rights reserved.

Keyword ：

epsilon-dominance Multi-objective optimization Non-dominated sorting Teaching-learning-based optimization

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Abstract ：

AIM: To evaluate the intraocular pressure (IOP) control of an artificial trabeculum drainage system (ATDS), a newly designed glaucoma drainage device, and postoperative complications in normal rabbit eyes. METHODS: Pressure drops in air and fluid of 30 ATDS were measured after being connected to a closed manometric system. Twenty of them were then chosen and implanted randomly into the eyes of 20 rabbits. Postoperative slit-lamp, gonioscopic examination and IOP measurements were recorded periodically. Ultrasound biomicroscopy and B-scan ultrasonography were also used to observe the complications. Eyes were enucleated on day 60. RESULTS: Pressure drops of 4.6-9.4 mm Hg were obtained at physiological aqueous flow rates in the tests in vitro. The average postoperative IOP of the experimental eyes (11.6-12.8 mm Hg) was lower than the controls significantly (P<0.05) at each time point. Complications of hemorrhage (n=1), cellulosic exudation (two cases) and local iris congestion (two cases) were observed. The lumina of the devices were devoid of obstructions in all specimens examined and a thin fibrous capsule was found around the endplate. CONCLUSION: ATDS reduce IOP effectively. However, further studies on the structure are needed to reduce complications.

Keyword ：

aqueous humor drainage device intraocular pressure outflow rabbit

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Abstract ：

本书共十一章, 内容包括绪论、凝胶注膜原理、陶瓷铸型坯体冷冻干燥、陶瓷铸型坯体脫脂工艺、陶瓷铸体综合性能、透平叶片快速制造等, 介绍了基于增材制造技术 (3D打印) 的空心叶片制造技术方法。

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In space geometric error modeling for machine tool of arbitrary structure, the motive axes error transfer chain must be obtained, which is used to finish error modeling based on differential transformation for machine tool of arbitrary structure. By using the theory of multi-body system, the topological structure and low body array for machine tool of arbitrary structure is established. Then by making use of the topological structure and the low body array of machine tool, the concepts of relative motion matrix of supporting parts connected by motive axes of machine tool and connected matrix of supporting parts are proposed and the mathematical model of acquiring error transfer chain of motive axes is built. This mathematical model combines the low body array describing the topological structure of machine tool and the relationship of relative motion of supporting parts of machine tool, which gives the modeling method on acquiring the motive axes error transfer chain of arbitrary machine tool. Additionally, error transfer chain of motive axes obtained by this modeling method is used in space geometric error modeling for machine tool based on differential transformation to realize the space geometric error modeling for machine tool of arbitrary structure. The modeling method's validity of motive axes error transfer chain is verified by examples of five-axis vertical machining center. © 2016 Journal of Mechanical Engineering.

Keyword ：

Arbitrary structures Differential transformation Geometric errors Multi Body Systems Relative motion Theory of multi-body system Topological structure Vertical machining centers

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An acoustic wave equation with considering small perturbation is presented first by use of the fluidic mechanics and aerodynamics, then a theoretical model for predicting the outlet noise of rolling piston compressors is investigated, and the sound pressure and sound power of the outlet noise are formulated based on the acoustic wave equation. The experimental data and simulation results for the outlet noise with different rotation velocities have been compared with the discrepancy less than 2.6%, which verifies the approach presented in this paper.

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The particle damping technique has been in development for several decades, and has been used successfully in many fields. However, it is difficult to predict its damping characteristics due to complex collisions and friction mechanisms, as well as high non-linear damping characteristics in dense particles. The focus of these current main achievements is centralized on the equivalent single degree of freedom (SDOF) system under free and forced vibration. In this paper, a brand new co-simulation approach for the continuum structure system based on the multiphase flow theory (MFT) of gas solid is developed by the COMSOL Multiphysics live link for MATLAB. A simple continuum structure system, (i.e., the cantilever particle damped beam) is made as an experiment. It is further shown that the damping capacity of a cantilever beam depends not only on the exerted location of the particle damper, but also the quantity of the filling. An experimental verification is performed, and an acceptable accordance is achieved between the theoretical results and the experimental data. It can be shown that the theoretical work in this paper is valid. The co-simulation method simplifies the complicated modelling problem, and offers the possibility to analyse the vibro-acoustic response prediction for complicated particle-damping composite structures.

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