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Differential Evolution-Optimized Multi-Output Support Vector Regression-Based Prediction of Weld Bead Morphology in Wire-Fed Laser-Arc Directed Energy Deposition of 2319 Aluminum Alloy

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Additive manufacturing Frontiers 2025年第2期4卷

作者： Li, Runsheng Ma, Hui Zeng, Kui Suo, Haoyuan Li, Chenyu Fu, Youheng Zhang, Mingbo Zhang, Maoyuan Fang, Xuewei College of Mechanical and Electronic Engineering China University of Petroleum (East China) Qingdao 266580 China The Ministry of Education Key Lab of Contemporary Design and Integrated Manufacturing Technolgy Northwestern Polytechnical University Xi'an 710072 China The State Key Laboratory for Manufacturing Systems Engineering School of Mechanical Engineering Xi'an Jiaotong University Xi'an 710054 China School of Material Science and Engineering Huazhong University of Science and Technology Wuhan 430070 China

Wire-fed laser-arc directed energy deposition (Wire-fed LA-DED) Technol. improves production speed while maintaining high quality and is particularly suited for manufacturing large, complex aluminum or titanium alloy components. The geometry of the weld bead (height and width) is influenced by multiple intricate parameters and variables during the manufacturing process. Accurately predicting the weld bead shape enables precise control over the surface flatness of the part, helping to prevent defects such as lack of fusion. This significantly reduces dimensional redundancy, enhances printing efficiency, and optimizes material usage. In this study, a quadratic regression prediction model for weld bead geometry was developed using the response surface methodology (RSM), with predictions generated through several machine learning models. These models included the backpropagation neural network (BPNN), support vector regression (SVR), multi-output support vector regression (MOSVR), extreme learning machine (ELM), and a differential evolution-optimized MOSVR (DE-MOSVR) model. Grid search and cross-validation techniques were utilized to identify the optimal parameters for each model to achieve the best predictive performance. A comparison of these models was conducted, followed by an evaluation of their generalization capabilities using an additional 20 sets of test data. The most accurate predictive model was selected based on a comprehensive assessment. The results showed that the DE-MOSVR model outperformed the others, achieving mean squared error, root mean squared error, mean absolute error, and R² values for width (height) predictions of 0.0411 (0.0041), 0.2028 (0.0639), 0.1671 (0.0550), and 0.9434 (0.9433), respectively. It demonstrated the smallest deviation in the validation set, with mean deviations of 1.97 % and 1.68 %, respectively. The model we developed was validated through the production of prototype parts, providing valuable reference and guidance for pred

关键词： 2319 aluminum alloy Differential evolution Geometry prediction Machine learning Wire-fed laser-arc directed energy deposition

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Three-dimensional weighting reconstruction algorithm for circular cone-beam CT under large scan angles

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Nuclear Science and Techniques 2017年第8期28卷 75-82页

作者： Ya-Fei Yang Ding-Hua Zhang Kui-Dong Huang Fu-Qiang Yang Zong-Zhao Gao Key Lab of Contemporary Design and Integrated Manufacturing Technology (Northwestern Polytechnical University) Ministry of Education Xi'an 710072 China

Improving imaging quality of cone-beam CT under large cone angle scan has been an important area of CT imaging research. Considering the idea of conjugate rays and making up missing data, we propose a three-dimensional(3D) weighting reconstruction algorithm for cone-beam CT. The 3D weighting function is added in the back-projection process to reduce the axial density drop and improve the accuracy of FDK algorithm. Having a simple structure, the algorithm can be implemented easily without rebinning the native cone-beam data into coneparallel beam data. Performance of the algorithm is evaluated using two computer simulations and a real industrial component, and the results show that the algorithm achieves better performance in reduction of axial intensity drop artifacts and has a wide range of application.

关键词：重建算法锥束CT 三维角度扫描加权性能评价轴向强度 FDK算法

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design Optimization of Irregular Cellular Structure for Additive manufacturing

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Chinese Journal of Mechanical Engineering 2017年第5期30卷 1184-1192页

作者： Guo-Hua Song Shi-Kai Jing Fang-Lei Zhao Ye-Dong Wang Hao Xing Jing-Tao Zhou School of Mechanical Engineering Beijing Institute of Technology Key Lab of Contemporary Design and Integrated Manufacturing Technology Ministry of EducationNorthwestern Polytechnical University

Irregularcellular structurehas great potential to be considered in light-weight design field. However, the research on optimizing irregular cellular structures has not yet been reporteddue to the difficulties in their modeling technology. Based on the variable density topology opti- mization theory, an efficient method for optimizing the topology of irregular cellular structures fabricated through additive manufacturing processes is proposed. The pro- posed method utilizes tangent circles to automatically generate the main outline of irregular cellular structure. The topological layoutof each cellstructure is optimized using the relative density informationobtained from the proposed modified SIMP method. A mapping relationship between cell structure and relative densityelement is builtto determine the diameter of each cell structure. The results show that the irregular cellular structure can be optimized with the proposed method. The results of simulation and experimental test are similar for irregular cellular structure, which indicate that the maximum deformation value obtained using the modified Solid Isotropic Microstructures with Penalization （SIMP） approach is lower 5.4× 10-5 mm than that using the SIMP approach under the same under the same external load. The proposed research provides the instruction to design the other irregular cellular structure.

关键词： Irregular cellular structure Additivemanufacturing Topology optimization Relative densitymapping

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Multi-resolution based cone-beam computed tomography high precision point cloud acquisition

Multi-resolution based cone-beam computed tomography high pr...

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Frontiers in Optics, FIO 2018

作者： Zheng, Jia Zhang, Dinghua Huang, Kuidong Sun, Yuanxi Key Lab. of Contemporary Design and Integrated Manufacturing Technology Ministry of Education School of Mechanical Engineering Northwestern Polytechnical University 127 West Youyi Road Xi'an Shaanxi710072 China

We improve disconnections in sub-pixels of cone-beam computed tomography (CBCT) slice images. The proposed method, which is based on the multi-resolution, can acquire more connective sub-pixels and point cloud with hi... 详细信息

ISBN: (纸本)9781943580460

关键词： Pixels

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Stress analysis and damage evolution in individual plies of notched composite laminates subjected to in-plane loads

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Chinese Journal of Aeronautics 2017年第1期30卷 447-460页

作者： Hu Junshan Zhang Kaifu Cheng Hui Liu Ping Zou Peng Song Danlong The Ministry of Education Key Lab of Contemporary Design and Integrated Manufacturing Technology Northwestern Polytechnical University Xi'an 710072 China School of Mechanical Engineering Northwestern Polytechnical University Xi'an 710072 China

This work aims to investigate local stress distribution, damage evolution and failure of notched composite laminates under in-plane loads. An analytic method containing uniformed boundary equations using a complex variable approach is developed to present layer-by-layer stresses around the notch. The uniformed boundary equations established in series together with conformal mapping functions are capable of dealing with irregular boundary issues around the notch and at infinity. Stress results are employed to evaluate the damage initiation and propagation of notched composites by progressive damage analysis（PDA）. A user-defined subroutine is developed in the finite element（FE） model based on coupling theories for mixed failure criteria and damage mechanics to efficiently investigate damage evolution as well as failure modes. Carbon/epoxy laminates with a stacking sequence of [45°/0°/ 60°/90°]sare used to investigate surface strains, in-plane load capacity and microstructure of failure zones to provide analytic and FE methods with strong validation. Good agreement is observed between the analytic method, the FE model and experiments in terms of the stress（strain） distributions, damage evaluation and ultimate strength, and the layerby-layer stress components vary according to a combination effect of fiber orientation and loading type, causing diverse failure modes in individuals.

关键词： Damage evolution Failure mode Failure strength Layer-by-layer stresses User-defined subroutine

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Operator Division and Production Parameter Solving Based on Fuzzy Clustering Method

Operator Division and Production Parameter Solving Based on ...

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IEEE International Conference on Software Engineering and Service Sciences (ICSESS)

作者： Yong Cao Jianhan Wang Yuan Li Lan Xu The Ministry of Education Key Lab of Contemporary Design and Integrated Manufacturing Technology Northwestern Poly technical University Xi'an Shaanxi China

ISBN: (纸本)9781538665664;9781538665657

A method of personnel classification based on operation time was presented. Considering the influence of accumulated operation time, historical attendance rate and professional technical training on post operation time, the weight coefficient of each influencing factor was determined by the AHP. Based on fuzzy clustering, operators were classified. By solving the similarity and aggregation, the operators were classified into three levels according to the assembly process. Finally, based on the classification results, the method to solve assembly cycle of each control unit was established, which lay the foundation for the operation balance.

关键词： Production Aircraft Personnel Surface treatment Workstations Analytic hierarchy process Clustering methods

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Mirror-Training of a Cable- Driven Hand Rehabilitation Robot Based on Surface Electromyography (sEMG)

Mirror-Training of a Cable- Driven Hand Rehabilitation Robot...

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International Conference on Intelligent Control and Information Processing (ICICIP)

作者： Jun Ma Rong Mo Miao Chen Long Cheng Hongsheng Qi Chongqing Tiema Industries Group Co. Ltd. Chongqing China Key Lab. of Contemporary Design and Integrated Manufacturing Technology Ministry of Education Northwestern Polytechnical University Xi'an China School of Artificial Intelligence University of Chinese Academy of Sciences Beijing China Key Lab. of Systems and Control Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing China

ISBN: (数字)9781728100159

ISBN: (纸本)9781728100166

In recent years, robots are widely used for helping post-stroke patients do rehabilitation training because it can provide long-term, accurate stimulation for motor function recovery. However, how to design a useful robot that can help patients do rehabilitation training such as separate movements and how to establish a human-robot interaction interface to increase the patient's involvement are challenging topics for the hand rehabilitation robot. Therefore, a hand exoskeleton robot has been designed to help the post-stroke patient do hand rehabilitation training with the aid of some advanced control methods. There are two notable features on this robot: 1) the active disturbance rejection controller is utilized to control the robot for a better control performance. Experimental results show that this controller can track the reference better than PID controller and can reject the disturbance as well; and 2) this paper creates a human-robot interaction interface to do active rehabilitation control (mirror-training). Firstly, this paper utilizes the back-propagation neural network to recognize the volunteer's movement intentions (hand gestures) based on surface electromyography (sEMG). Then, the corresponding hand-gesture recognition result is used to control the hand exoskeleton. The result shows that the rehabilitation robot can follow the volunteer's movement intention to fulfill the mirror-training of the patient.

关键词： Machine-to-machine communications Intelligent control Information processing Hafnium TV Synthetic aperture sonar

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A Fast and Robust Calibration Method for Geometric Parameters of Cone-beam CT

A Fast and Robust Calibration Method for Geometric Parameter...

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2017 International MultiConference of Engineers and Computer Scientists, IMECS 2017

作者： Zhang, Hua Zhang, Caixin Zhang, Dinghua Dong, Yin Chang, Taoqi Huang, Kuidong School of Mechanical Engineering Northwestern Polytechnical University Xi’an Shaanxi710072 China Key Lab of Contemporary Design and Integrated Manufacturing Technology Northwestern Polytechnical University Ministry of Education Xi’an Shaanxi710072 China Key Lab of Contemporary Design and Integrated Manufacturing Technology Northwestern Polytechnical University Ministry of Education Xi’an Shaanxi710072 China CAPC Xi'an Precision Casting Co. Ltd Xi’an Shaanxi710021 China CAPC Xi'an Precision Casting Co. Ltd Xi’an Shaanxi710021 China Key Lab of Contemporary Design and Integrated Manufacturing Technology Northwestern Polytechnical University Ministry of Education Xi’an Shaanxi710072 China

ISBN: (纸本)9789881404732

At present, the cone-beam CT (CBCT) technology has been widely used in biomedical and non-destructive testing. The calibration of the geometric parameters of CBCT is the prerequisite for accurate image reconstruction. Inaccurate geometric parameters can lead to artifacts in reconstructed CBCT images and reduce the image quality. In order to obtain the geometric parameters of CBCT quickly and reliably, a calibration method for geometric parameters based on wire scanning is proposed in this paper. Firstly, a simple calibration tool is designed. Its basic structure is metal filament embedded in plexiglass tube. And then obtain a small amount of projections of the calibration tool with a single circular trajectory scanning, and superimpose the scanned projections. The coordinate of the beam center can be obtained by performing rotational axis fitting based on the symmetrical characteristics of the superimposed projection. After that, collect the projection after the calibration tool moves a certain distance, the distance between the focus and the rotation center, and the distance from the focus to the detector, are calculated according to the corresponding geometric relation of the calibration tool diameter and its projection. The simulation results and actual scan results show that the method can obtain the accurate geometric parameters of CBCT, which has the characteristics of a small amount of scanning, fast calibration speed and strong robustness. And it has been successfully applied in small focus CBCT and micro focus CBCT.

关键词： Edge detection

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Damage analysis on sleeve-bolt interference-fit installing process of composite

Damage analysis on sleeve-bolt interference-fit installing p...

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第二十一届国际复合材料大会

作者： Peng Zou Kaifu Zhang Hui Cheng Fan Qu Guanhua Xu The Ministry of Education Key Lab of Contemporary Design and Integrated Manufacturing Technology Northwestern Polytechnical University

Interference-fit bolts can lower the stress concentration thereby increasing the fatigue life of composite structures. However, traditional installation method of inference-fit bolts is prone to cause damage especially delamination around the hole,thus decreases the structure strength. In order to solve the problem, a study on new sleeve-type interference-fit fastener installation process was carried out. The damage mechanism was analyzed and compared between two joint-styles from both finite-element model and experiment. Firstly, a finite-element model based on progressive damage theory and traction-displacement law of cohesive element was built to analyze the installation force and damage onset for different interference-fit percentage. Then, a comparing experiment was carried out. The specimens are observed under industrial Computed Tomography（CT） and scanning electron microscope（SEM）. The finite-element results were compared with experimental ones,and the reality of the model was verified. The research shows that the sleeve-type bolt can reduce delamination damage effectively. Reasons for this result are analyzed and discussed.

关键词： interference-fit sleeve-type fastener installation process delamination damage mechanism

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Robust scatter correction method for cone-beam CT using an interlacing-slit plate

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Chinese Physics C 2016年第6期40卷 95-102页

作者：黄魁东徐哲张定华张华时稳龙 Key Lab of Contemporary Design and Integrated Manufacturing Technology of the Ministry of Education Northwestern Polytechnical University School of Mechanical Engineering Northwestern Polytechnical University

Cone-beam computed tomography （CBCT） has been widely used in medical imaging and industrial nondestructive testing, but the presence of scattered radiation will cause significant reduction of image quality. In this article, a robust scatter correction method for CBCT using an interlacing-slit plate （ISP） is carried out for convenient practice. Firstly, a Gaussian filtering method is proposed to compensate the missing data of the inner scatter image, and simultaneously avoid too-large values of calculated inner scatter and smooth the inner scatter field. Secondly, an interlacing-slit scan without detector gain correction is carried out to enhance the practicality and convenience of the scatter correction method. Finally, a denoising step for scatter-corrected projection images is added in the process flow to control the noise amplification The experimental results show that the improved method can not only make the scatter correction more robust and convenient, but also achieve a good quality of scatter-corrected slice images.

关键词： CBCT scatter correction image fusion interlacing-slit noise control

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