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Reinforcement learning method for machining deformation control based on meta-invariant feature space

Visual Computing for Industry,Biomedicine,and Art 2022年第1期5卷 323-339页

作者： Yujie Zhao Changqing Liu Zhiwei Zhao Kai Tang Dong He College of Mechanical and Electrical Engineering/National Key Laboratory of Science and Technology on Helicopter Transmission Nanjing University of Aeronautics and AstronauticsNanjing 210016China The Smart Manufacturing Thrust Hong Kong University of Science and Technology(GZ)Guangzhou 511458China

Precise control of machining deformation is crucial for improving the manufacturing quality of structural aerospace components.In the machining process,different batches of blanks have different residual stress distributions,which pose a significant challenge to machining deformation control.In this study,a reinforcement learning method for machining deformation control based on a meta-invariant feature space was developed.The proposed method uses a reinforcement-learning model to dynamically control the machining process by monitoring the deformation force.Moreover,combined with a meta-invariant feature space,the proposed method learns the internal relationship of the deformation control approaches under different stress distributions to achieve the machining deformation control of different batches of blanks.Finally,the experimental results show that the proposed method achieves better deformation control than the two existing benchmarking methods.

关键词： Machining deformation Residual stress deformation control Meta-invariant feature space Reinforcement learning

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Weld deformation control based on programmable multi-point flexible support

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China Welding 2022年第3期31卷 30-34页

作者：肖珺雷一鼎陈树君芦伟何恩光 Engineering Research Center of Advanced Manufacturing Technology for Automotive Components Ministry of EducationBeijing University of TechnologyBeijing 100124China Science and Technology on Power Beam Processes Laboratory Manufacturing Technology InstituteBeijing 100024China

T-joint titanium alloy structures are commonly used in aircraft manufacturing,and their laser welding process is relatively mature,but due to the strict requirements of the airplane production,the angular deformation caused by uneven heat input across the sheet is still not negligible,so active control needs to be imposed.In this paper,an active deformation control method based on programmable multi-point flexible support is proposed and validated.In response to the problem that the traditional rigid clamping and pre-stressing are not adapted to the T-structure thin sheet,this study has designed a multi-point flexible support with microcontroller and electric actuators,which can monitor the stress state of the current support position in real time during the welding process and make dynamic adjustment,so that the weld deformation could be effectively reduced in this way.

关键词： laser welding deformation control flexible support force control

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An allowance allocation method based on dynamic approximation via online inspection data for deformation control of structural parts

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Chinese Journal of Aeronautics 2020年第12期33卷 3495-3508页

作者： Xiaozhong HAO Yingguang LI Chong HUANG Mengqiu LI Changqing LIU Kai TANG National Key Laboratory of Science and Technology on Helicopter Transmission Nanjing University of Aeronautics and AstronauticsNanjing 210016JiangsuChina Hong Kong University of Science and Technology Hong KongChina

deformation resulting from residual stress has been a significant issue in machining.As allowance allocation can directly impact the residual stress on part deformation,it is essential for deformation control.However,it is difficult to adjust allowance allocation by traditional simulation methods based on residual stress,as the residual stress cannot be accurately measured or predicted,and many unexpected factors during machining process cannot be simulated accurately.Different from traditional methods,this paper proposes an allowance allocation method based on dynamic approximation via online inspection data for deformation control of structural parts.An Autoregressive Integrated Moving Average(ARIMA)model for dynamic allowance allocation is established so as to approach the minimum deformation,which is based on the in-process deformation inspection data during the alternative machining process of upside and downside.The effectiveness of the method is verified both by simulation cases and real machining experiments of aircraft structural parts,and the results show that part deformation can be significantly reduced.

关键词： ARIMA model deformation control deformation inspection data Machining allowance allocation Structural parts

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A generalized multi-field coupling approach and its application to stability and deformation control of a high slope

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Journal of Rock Mechanics and Geotechnical Engineering 2011年第3期3卷 193-206页

作者： Chuangbing Zhou Yifeng Chen Qinghui Jiang Wenbo Lu State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan 430072 China Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering of Ministry of Education Wuhan University Wuhan 430072 China

Human activities, such as blasting excavation, bolting, grouting and impounding of reservoirs, will lead to disturbances to rock masses and variations in their structural features and material properties. These engineering disturbances are important factors that would alter the natural evolutionary processes or change the multi-field interactions in the rock masses from their initial equilibrium states. The concept of generalized multi-field couplings was proposed by placing particular emphasis on the role of engineering disturbances in traditional multi-field couplings in rock masses. A mathematical model was then developed, in which the effects of engineering disturbances on the coupling-processes were described with changes in boundary conditions and evolutions in thermo-hydro-mechanical （THM） properties of the rocks. A parameter, d, which is similar to damage variables but has a broader physical meaning, was conceptually introduced to represent the degree of engineering disturbances and the couplings among the material properties. The effects of blasting excavation, bolting and grouting in rock engineering were illustrated with various field observations or theoretical results, on which the degree of disturbances and the variations in elastic moduli and permeabilities were particularly focused. The influences of excavation and groundwater drainage on the seepage flow and stability of the slopes were demonstrated with numerical simulations. The proposed approach was further employed to investigate the coupled hydro-mechanical responses of a high rock slope to excavation, bolting and impounding of the reservoir in the dam left abutment of Jinping I hydropower station. The impacts of engineering disturbances on the deformation and stability of the slope during construction and operation were demonstrated.

关键词： generalized multi-field couplings engineering disturbance slope stability deformation control

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Numerical study on lateral wall displacement of deep excavation supported by IPS earth retention system

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Underground Space 2017年第4期2卷 259-271页

作者： Tugen Feng Long Liu Tao Tong Mi Zhou Key Laboratory of M inistry of Education for Geomechanics and Embankment Engineering Jiangsu Research Center for Geotechnical Engineering TechnologyHohai University1 Xikang RdNanjing 210098China Survey and Design Research Institute of Jiangxi Province 169 Zhiyang RdNanchang 330095China School of Civil and Transportation Engineering State Key labor atory of Subtropical Building ScienceSouth China University of Techmnology381 Wushan RoadGuangzhou 510640China

The objective of this study is to investigate the 3D behavior characteristics of an excavation supported by an innovative prestressed support(IPS)earth retention system.A numerical simulation was conducted in order to provide insight into the IPS system behavior by using the FLAC3D package.Prior to the parametric study,validation work was conducted by means of a comparison of the deformation between theﬁeld test data and numerical analysis results,and strong agreement was obtained.The reasonable excavation location,lay-ered excavation thickness,and blocked excavation sequence are presented according to variable parameter analysis.In view of the pre-viousﬁndings,certain measurements are proposed in order to control the foundation pit deformation.The results indicate that prestress compensation has a signiﬁcant effect on the IPS system behavior,while an optimized excavation sequence slightly improves its behavior.With the conclusion proposed based on the numerical results,the aim is to provide reference data for optimization design and the construction sequence.

关键词： FLAC3D IPS system Prestress compensation Layered excavation Blocked excavation deformation control

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3D Printing of Stretchable Strain Sensor Based on Continuous Fiber Reinforced Auxetic Structure

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Chinese Journal of Mechanical Engineering(Additive Manufacturing Frontiers) 2023年第2期2卷 11-18页

作者： Wanquan Yan Xiaoyong Tian Daokang Zhang Yanli Zhou Qingrui Wang State Key Laboratory for Manufacturing Systems Engineering Xi’an Jiaotong UniversityXi’an710049China

Stretchable strain sensors play a key role in motion detection and human-machine interface functionality,and deformation control.However,their sensitivity is often limited by the Poisson effect of elastic substrates.In this study,a stretchable strain sensor based on a continuous-fiber-reinforced auxetic structure was proposed and fabricated using a direct ink writing(DIW)3D printing process.The application of multi-material DIW greatly simplifies the fabrication process of a sensor with an auxetic structure(auxetic sensor).The auxiliary auxetic struc-ture was innovatively printed using a continuous-fiber-reinforced polydimethylsiloxane composite(Fiber-PDMS)to balance the rigidity and flexibility of the composite.The increase in stiffness enhances the negative Poisson’s ratio effect of the auxetic structure,which can support the carbon nanotube-polydimethylsiloxane composite(CNT-PDMS)stretchable sensor to produce a significant lateral expansion when stretched.It is shown that the structural Poisson’s ratio of the sensor decreased from 0.42 to−0.33 at 20%tensile strain,and the bidirectional tensile strain increases the sensor sensitivity by 2.52 times(gage factor to 18.23).The Fiber-PDMS composite maintains the excellent flexibility of the matrix material.The auxetic sensor exhibited no structural damage af-ter 150 cycles of tension and the signal output exhibited high stability.In addition,this study demonstrates the significant potential of auxetic sensors in the field of deformation control.

关键词： 3D printing Stretchable sensor Auxetic structure Continuous fiber Sensitivity deformation control

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Research on Inherent Strain Distribution in Welded Low-Alloy Components

Research on Inherent Strain Distribution in Welded Low-Alloy...

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第三届国际机械工程与力学会议

作者： Yazhi LI Hongbin ZHOU Qingju ZHU College of Civil Engineering and Mechanics Yanshan University

Inherent strain FEM is a recently developed numerical technique to forecast welding residual deformations. It makes use of the concept of inherent strain distribution to effectively reduce the analysis of the very complex highly nonlinear welding process to an equivalent linear elastic FEA, thus the computational cost could be significantly reduced. In this paper, the inherent strain coefficients for the welding process of low-alloy high tensile strength steel Q345 have been derived by using both elastic-plastic finite element analyses and experimental studies of twelve bead-on-plate specimens. It has been found that the results from the two methods compare well. Using the inherent strain coefficients derived, an example application of the inherent strain FEM to a real life welding process has been demonstrated.

关键词： inherent strain low-alloy steel numerical simulation welding deformation deformation control

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Soil Disturbance and the Environmental Stability control in Urban Areas under Shield Tunneling

Soil Disturbance and the Environmental Stability Control in ...

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作者： Sun Jun (Research Studio of Academicians,Group of Urban Construction,Shanghai Research Institute of Geotechnical Engineering,Tongji University,Shanghai 200092,China)

The mechanism of circumferential soil disturbance under shield tunnel driving in soft ground is discussed in this paper.Corresponding longitudinal and transversal soil settlement troughs(basins) on the ground surface are predicted respectively for different conditions as:(1) a single shield for to-and-fro driving both,on the upward and the downward lines in a same route-segment of the double-line subway(metro);and(2) two shields for parallel driving in the same or opposite direction.Also,the sensibility analysis is made for evaluation of tunnel lining design parameters as compared with its measured values.A stipulation for a index system related soil deformation control in tunnel construction aiming at different permissible standards of circumferential soil displacement is proposed.Suggestions for the sake of real-time adjustment of design and construction parameters of the tunnel shields in order to keep the soil stability and to maintain the safety of construction site circumstances through effective soil deformation control are also put forward.

关键词： soil disturbance environment prediction deformation control subway tunnel shield

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