Stiffness Evaluation of an Adsorption Robot for Large-scale Structural Parts Processing

2021 ◽  
pp. 1-14
Author(s):  
Jiakai Chen ◽  
Fugui Xie ◽  
Xin-Jun Liu ◽  
Weiyao Bi
Keyword(s):  
Large Scale ◽  
Parallel Robots ◽  
Modeling Method ◽  
Machining Process ◽  
Element Analysis ◽  
Stiffness Modeling ◽  
Stiffness Evaluation ◽  
Machining Robot ◽  
Structural Parts ◽  
Five Axis

Abstract Efficient and economical processing of large-scale structural parts is in increasing need and is also a challenging issue. In this paper, an adsorption machining robot for processing of large-scale structural parts is presented. It has potential advantages in flexible, efficient and economical processing of large-scale structural parts because of the adsorption ability. Stiffness is one of the most important performance for machining robots. In order to investigate the stiffness of the robot in the workspace, the kinematics of the adsorption manipulator, the five-axis machining manipulator and the adsorption machining robot is derived step by step. Then with the help of Finite Element Analysis (FEA), a stiffness modeling method considering the compliance of the base is proposed. A stiffness isotropy index is put forward to evaluate the robot's overall stiffness performance by taking all possible working conditions into consideration. Based on the index, stiffness evaluation in the reachable workspace is carried out and an optimized workspace is identified considering the overall stiffness magnitude, stiffness isotropy and workspace volume, which will be used in the machining process. The stiffness modeling method and stiffness isotropy index proposed in the paper are universal and can be applied to other parallel robots.

scholarly journals Experimental and simulation study on chatter stability region of integral impeller with non-uniform allowance

2020 ◽  
Vol 103 (3) ◽  
pp. 003685042093341
Author(s):  
Yan Wu ◽  
Kaifa Wang ◽  
Gang Zheng ◽  
Boxin Lv ◽  
Yong He
Keyword(s):  
Natural Frequency ◽  
Stability Region ◽  
Tool Path ◽  
Surface Profile ◽  
Machining Process ◽  
Chatter Stability ◽  
Element Analysis ◽  
Impeller Blade ◽  
Five Axis ◽  
Milling Chatter

In order to accurately improve and predict chatter stability region of machining process, an optimization method of machining process with non-uniform allowance of integral impeller was proposed. The modal parameters of the workpiece process system were obtained using the finite element analysis. Based on the regenerative chatter analysis theory, a limit comparison diagram of the stability with uniform allowance and non-uniform allowance was established. The simulation results showed that the non-uniform allowance natural frequency is about 1.43 times as much as the uniform allowance natural frequency, and the machining system stiffness non-uniform allowance is twice as much as the uniform allowance, while the limit of chatter stability region is increased by 3 times. This article studied uniform allowance and non-uniform allowance of milling chatter stability with experimental method. Tool path for five-axis machining and machine tool simulation based on NX CAM were planned. The comparisons of cutting processing uniform allowance and non-uniform allowance were done, and the surface profile detection of the test part with the three-dimensional scanning was carried out. The experimental results showed that the average optimization rate for manufacturing precision of blade suction surface after optimization and pressure surface was 63.8% and 48.84%. The total experiment showed that this process optimization strategy could effectively improve the stiffness of the integral impeller blade and reduce the cutting chatter of the blade during the cutting process.

Multiscale Modeling of a Notched Coupon Test for Triaxially Braided Composites

2019 ◽  
Vol 795 ◽  
pp. 172-179
Author(s):  
Yan Qi Hu ◽  
Wieslaw K. Binienda
Keyword(s):  
Multiscale Modeling ◽  
Large Scale ◽  
Laminated Composite ◽  
High Strength ◽  
Multiscale Model ◽  
Tensile Tests ◽  
Local Deformation ◽  
Modeling Method ◽  
Braided Composites ◽  
Element Analysis

Braided composites have been widely used in aerospace and automotive structures due to their light weight and high strength. Unlike metal or laminated composite material, the complex braided structure brings a lot of challenges when conducting numerical simulation. In this paper, a finite element analysis based meso-mechanical modeling for the two dimensional triaxially braided composite was developed. This mesoscale modeling method is capable of considering the detailed braiding geometry and architecture as well as the mechanical behavior of fiber tows, matrix and the fiber tow interface. Furthermore, a multiscale model combined both macroscale and mesoscale approaches and it is realized within LS-DYNA environment through Interface_components and Interface_linking. This combined multiscale modeling approach enables the full advantage of both the macroscale and mesoscale approaches, which can describe the details of local deformation and the global overall response features of the entire structure with the minimum computational expense. The evaluation and verification of the mesoscale approach and combined multiscale modeling method is through a notched coupon tensile tests conducted by Kohlman in both axial and transverse direction. The multiscale modeling method captures the response feature accurately so it has the ability to analyze large scale structures.

scholarly journals Research and Application of High Precision Machining Technology for Super-Large Integral Frame Parts of Aluminum Alloy

2020 ◽  
Author(s):  
Hong Ji ◽  
Yujie Wang ◽  
Yu Peng ◽  
Lixin Zhao ◽  
Song Huang
Keyword(s):  
Aluminum Alloy ◽  
Error Control ◽  
Large Scale ◽  
Dimensional Accuracy ◽  
Machining Process ◽  
Processing Efficiency ◽  
Deformation Control ◽  
Large Size ◽  
Structural Parts ◽  
Large Aircraft

Compared with ordinary large-scale structural parts, super-large aircraft aluminum alloy integral frame parts have the characteristics of large size, high ribs and thin-walled, which lead to the difficulty of deformation control and dimensional accuracy assurance in the machining process, and the problems of spring knife and broach are easy to occur. In this paper, the research on super-large aluminum alloy integral frame parts is carried out, and a set of methods with part deformation control and coordinate drift error control are proposed, and the processing programming strategy is further optimized. This method has been successfully applied to a super-large aircraft aluminum alloy integral frame part, which greatly reduces the deformation of parts, improves the processing stability, and improves the processing efficiency by about 30%.

scholarly journals Design and Control of a Open-Source, Low Cost, 3D Printed Dynamic Quadruped Robot

2021 ◽  
Vol 11 (9) ◽  
pp. 3762
Author(s):  
Joonyoung Kim ◽  
Taewoong Kang ◽  
Dongwoon Song ◽  
Seung-Joon Yi
Keyword(s):  
Open Source ◽  
Low Cost ◽  
Quadruped Robot ◽  
Machining Process ◽  
Direct Drive ◽  
Depth Sensor ◽  
Element Analysis ◽  
Wide Range ◽  
3D Printed ◽  
Structural Parts

In this paper, we present a new open source dynamic quadruped robot, PADWQ (pronounced pa-dook), which features 12 torque controlled quasi direct drive joints with high control bandwidth, as well as onboard depth sensor and GPU-equipped computer that allows for a highly dynamic locomotion over uncertain terrains. In contrast to other dynamic quadruped robots based on custom actuator and machined metal structural parts, the PADWQ is entirely built from off the shelf components and standard 3D printed plastic structural parts, which allows for a rapid distribution and duplication without the need for advanced machining process. To make sure that the plastic structural parts can withstand the stress of dynamic locomotion, we performed finite element analysis (FEA) on leg structural parts as well as a continuous walking test using the physical robot, both of which the robot has passed successfully. We hope this work to help a wide range of researchers and engineers that need an affordable, highly capable and easily customizable quadruped robot.

On machining dynamics of flexible parts

2001 ◽  
Vol 215 (1) ◽  
pp. 53-59 ◽  
Author(s):  
F Abrari ◽  
M A Elbestawi ◽  
A D Spence
Keyword(s):  
Cutting Forces ◽  
Computer Aided Design ◽  
Process Model ◽  
Tool Path ◽  
Cutting Tool ◽  
Machining Process ◽  
Research Progress ◽  
Element Analysis ◽  
Flexible Parts ◽  
Five Axis

Solid modellers are now well established for computer aided design of mechanical parts. Machining applications, however, remain limited to geometric tool path planning. The physical aspects of the process are largely ignored. Success in actual machining, however, depends on consideration of cutting forces, torques, part and tool deflection, chatter, tool breakage and wear. This paper reports research progress towards a comprehensive simulation of the physical machining process of thin flexible parts. The system is based on extensions to a commercially available solid modeller. Cutting tool location data (CL-DATA) files along with an initial solid model of the workpiece are inputs. Each tool motion is segmented into short steps along the path and angular increments of spindle rotation. At each simulation step, immersion of the cutting tool teeth with the part is calculated. This information is then used by a machining process model to calculate cutting forces and tool/workpiece deflection. Up to five-axis motion is supported using a sweep representation of the tool swept volume. Flexible tools are modelled as cantilevers; flexible parts are created as solid models, are meshed and are dynamically solved using finite element analysis. The mesh is updated as material is machined away from the part.

scholarly journals Stator Non-Uniform Radial Ventilation Design Methodology for a 15 MW Turbo-Synchronous Generator Based on Single Ventilation Duct Subsystem

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2760
Author(s):  
Ruiye Li ◽  
Peng Cheng ◽  
Hai Lan ◽  
Weili Li ◽  
David Gerada ◽  
...  
Keyword(s):  
Finite Element ◽  
Temperature Distribution ◽  
Design Methodology ◽  
Large Scale ◽  
Synchronous Generator ◽  
Axial Direction ◽  
Scale Model ◽  
Element Analysis ◽  
Axial Temperature ◽  
Ventilation Duct

Within large turboalternators, the excessive local temperatures and spatially distributed temperature differences can accelerate the deterioration of electrical insulation as well as lead to deformation of components, which may cause major machine malfunctions. In order to homogenise the stator axial temperature distribution whilst reducing the maximum stator temperature, this paper presents a novel non-uniform radial ventilation ducts design methodology. To reduce the huge computational costs resulting from the large-scale model, the stator is decomposed into several single ventilation duct subsystems (SVDSs) along the axial direction, with each SVDS connected in series with the medium of the air gap flow rate. The calculation of electromagnetic and thermal performances within SVDS are completed by finite element method (FEM) and computational fluid dynamics (CFD), respectively. To improve the optimization efficiency, the radial basis function neural network (RBFNN) model is employed to approximate the finite element analysis, while the novel isometric sampling method (ISM) is designed to trade off the cost and accuracy of the process. It is found that the proposed methodology can provide optimal design schemes of SVDS with uniform axial temperature distribution, and the needed computation cost is markedly reduced. Finally, results based on a 15 MW turboalternator show that the peak temperature can be reduced by 7.3 ∘C (6.4%). The proposed methodology can be applied for the design and optimisation of electromagnetic-thermal coupling of other electrical machines with long axial dimensions.

scholarly journals Multi-Stage Cold Forging Process for Manufacturing a High-Strength One-Body Input Shaft

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 532
Author(s):  
A Jo ◽  
Myeong Jeong ◽  
Sang Lee ◽  
Young Moon ◽  
Sun Hwang
Keyword(s):  
High Strength ◽  
Microstructural Characterization ◽  
Fatigue Tests ◽  
Machining Process ◽  
Cold Forging ◽  
Element Analysis ◽  
Forging Process ◽  
Input Shaft ◽  
Multi Stage ◽  
The One

A multi-stage cold forging process was developed and complemented with finite element analysis (FEA) to manufacture a high-strength one-body input shaft with a long length body and no separate parts. FEA showed that the one-body input shaft was manufactured without any defects or fractures. Experiments, such as tensile, hardness, torsion, and fatigue tests, and microstructural characterization, were performed to compare the properties of the input shaft produced by the proposed method with those produced using the machining process. The ultimate tensile strength showed a 50% increase and the torque showed a 100 Nm increase, confirming that the input shaft manufactured using the proposed process is superior to that processed using the machining process. Thus, this study provides a proof-of-concept for the design and development of a multi-stage cold forging process to manufacture a one-body input shaft with improved mechanical properties and material recovery rate.

scholarly journals Study on the High-Speed Milling Performance of High-Volume Fraction SiCp/Al Composites

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4143
Author(s):  
Youzheng Cui ◽  
Shenrou Gao ◽  
Fengjuan Wang ◽  
Qingming Hu ◽  
Cheng Xu ◽  
...  
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Volume Fraction ◽  
Simulation Analysis ◽  
Cutting Temperature ◽  
High Volume ◽  
Cutting Parameters ◽  
High Volume Fraction ◽  
High Wear Resistance ◽  
Element Analysis

Compared with other materials, high-volume fraction aluminum-based silicon carbide composites (hereinafter referred to as SiCp/Al) have many advantages, including high strength, small change in the expansion coefficient due to temperature, high wear resistance, high corrosion resistance, high fatigue resistance, low density, good dimensional stability, and thermal conductivity. SiCp/Al composites have been widely used in aerospace, ordnance, transportation service, precision instruments, and in many other fields. In this study, the ABAQUS/explicit large-scale finite element analysis platform was used to simulate the milling process of SiCp/Al composites. By changing the parameters of the tool angle, milling depth, and milling speed, the influence of these parameters on the cutting force, cutting temperature, cutting stress, and cutting chips was studied. Optimization of the parameters was based on the above change rules to obtain the best processing combination of parameters. Then, the causes of surface machining defects, such as deep pits, shallow pits, and bulges, were simulated and discussed. Finally, the best cutting parameters obtained through simulation analysis was the tool rake angle γ0 = 5°, tool clearance angle α0 = 5°, corner radius r = 0.4 mm, milling depth ap = 50 mm, and milling speed vc= 300 m/min. The optimal combination of milling parameters provides a theoretical basis for subsequent cutting.

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