scholarly journals Theoretical Calculation and Simulation Analysis of Axial Static Stiffness of Double-Nut Ball Screw with Heavy Load and High Precision

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Haitao Luo ◽  
Jia Fu ◽  
Lichuang Jiao ◽  
Fengqun Zhao
Keyword(s):  
Finite Element ◽  
Axial Load ◽  
Simulation Analysis ◽  
Hertzian Contact ◽  
Ball Screw ◽  
Deformation Model ◽  
Heavy Duty ◽  
Static Stiffness ◽  
Feed System ◽  
Friction Stir

Double-nut ball screws bear the action of bidirectional pretightening force, leading to the deformation of the contact area between the ball and the raceway. Under this condition, it is important to analyze and calculate the static stiffness of the ball screw. However, the conventional calculation method is inaccurate. Hence, a new method for the static stiffness analysis of a double-nut ball screw is proposed. Through the structural analysis of the ball screw and internal load distribution, a load deformation model was established based on the Hertzian contact theory. Through the load analysis of the ball screw, a static stiffness model of the ball screw was established and applied to a case study and a finite element simulation. The rigidity of THK double-nut ball screws used in the X-axis feed system of a high-stiffness heavy-duty friction stir welding robot (developed by the research group) was calculated. When the workload was lower than 1.1 × 104 N, the slope of the double-nut static stiffness curve increased significantly with the increase in the workload, and when the workload was greater than 1.1 × 104 N, its upward slope tended to stabilize. The simulated and experimental stiffness curves were in good agreement; when the external axial load was greater than 2.8 × 104 N, the stiffness value calculated using the finite element method gradually converged to the theoretical value; and when the axial load reached 3.0 × 104 N, the simulation and test curves matched well. The analysis method of the double-nut ball screw was found to be concise and accurate, and the stiffness curves calculated using the two methods were consistent. The simulation analysis of the static stiffness presented herein is expected to aid the design of double-nut ball screws of high-rigidity heavy-duty equipment.

Static Stiffness Optimization of Large Ram Based on Equivalent Elastic Modulus

2014 ◽  
Vol 621 ◽  
pp. 9-18 ◽  
Author(s):  
Feng He Wu ◽  
Xiao Peng Xu ◽  
Jun Wang ◽  
Jun Wei Fan
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Large Scale ◽  
Optimization Procedure ◽  
Element Model ◽  
Heavy Duty ◽  
Static Stiffness ◽  
Stiffness Optimization ◽  
Finite Element Technology ◽  
Bending Load

The finite element model of heavy-duty machine tool’s ram components has a large number of elements, many contact pairs for assembly and a large-scale optimization calculation, which make the optimization difficult to conduct. To solve this problem, a static stiffness optimization method of the large component based on the equivalent elastic modulus is put forward. The proposed method is applied to super-heavy-duty CNC floor-type milling and boring machine of TK6932 as a case study. Based on the principle of the equivalent stiffness, the ram assembly with complex constraints and contacts is equivalent to a ram part without other components, the calculation method of the equivalent elastic modulus is analyzed and the equivalent elastic modulus formula of the ram under the bending load is derived. Taking the four box-walls’ thickness and the three stiffened-plates’ thickness of the ram as the optimization variables, the minimal volume under static loading as the target and the maximal displacement and stress as the constraints, the optimized mathematical model of the ram’s equivalent static stiffness is established. The results of the optimization are rounded according to the sensitivity analysis. Besides, the optimization effect is proved by simulation through the finite element technology. The optimization procedure and results show that the simplified method based on equivalent elastic modulus presented in the paper can control the calculation scale effectively, and ensure the process of the optimization smooth.

Tool with Heavy-Duty Machining Tube Section of the Fatigue Analysis

2011 ◽  
Vol 188 ◽  
pp. 344-347 ◽  
Author(s):  
Zhong Guang Yu ◽  
Xian Li Liu ◽  
Yuan Sheng Zhai ◽  
Geng Huang He ◽  
M. Li
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Structural Design ◽  
Stress Condition ◽  
Cutting Tool ◽  
Simulation Analysis ◽  
Heavy Duty ◽  
Analysis Software ◽  
Tool Stress ◽  
Lathe Tool

Because the tube festivals surface is not round, uneven, so the cutting tool is under impact unceasingly in cutting process. Cutting tool is extremely easy to have fatigue failure, therefore it is very necessary to use finite element numerical analysis software ANSYS to carry on numerical simulation analysis for heavy lathe tool intensity static. The force of cutting tool and distributed rule of definite cutting tool internal stress strain could be precisely got by using FEM, thus the analysis results could improve cutting tool stress condition and the structural design provides the theory basis

Modeling and Simulation for the Feed System of CNC Machine

2014 ◽  
Vol 496-500 ◽  
pp. 1024-1027
Author(s):  
Qin Wu ◽  
Jian Jun Yang ◽  
Chun Li Lei
Keyword(s):  
Driving Force ◽  
Simulation Analysis ◽  
Multiple Solution ◽  
Ball Screw ◽  
Nonlinear Stiffness ◽  
Cnc Machine ◽  
Feed System ◽  
Damping Force ◽  
System Use ◽  
Linear And Nonlinear

Study the linear and nonlinear stiffness dynamic characteristics of ball screw in feed system. According to the structure and the stiffness of ball screw, considering the influence of damping force, elastic force, friction force, driving force and load, establish the dynamic model of feed system. Use Linz Ted- Poincare (L-P) Method of singular perturbation to solve the model, obtain the quadratic approximate solution of the free vibration, analyze the multiple solution phenomenon of the model, and also conduct the numerical simulation analysis for the model.

Dynamic characteristics analysis and experimental of differential dual drive servo feed system

2021 ◽  
pp. 095440622110179
Author(s):  
Hanwen Yu ◽  
Laigang Zhang ◽  
Chong Wang ◽  
Xianying Feng
Keyword(s):  
Degrees Of Freedom ◽  
Electromechanical Coupling ◽  
Simulation Analysis ◽  
Drive System ◽  
Ball Screw ◽  
Parameter Method ◽  
Feed Speed ◽  
Feed System ◽  
Stick Slip ◽  
Low Speed

This paper presents the design for a new differential-dual-drive low-speed micro-feed mechanism. The ‘nut rotary ball screw pair’ is the main driving component of the mechanism. The screw and nut are each driven by a servo motor and these motors rotate in the same direction at a similar speed. The nonlinear factors such as friction and backlash can lead to unstable behaviours such as stick-slip and oscillation of the feed system. We use the Euler–Bernoulli beam elements, which have axial and torsional degrees of freedom, to describe the axial and torsional vibration of the ball screw, and use the spring-lumped parameter method to analyse other components of the feed system. An electromechanical coupling dynamic model with nonlinear factors of friction and clearance is established. Through simulation analysis and experiment, the difference in response of single-drive and differential-dual-drive systems under the influence of friction and clearance is studied. The results show that the nonlinear factors of friction and clearance have an influence on the feed speed of single-drive and differential-dual-drive system, but the low-speed micro-feed performance of the differential-dual-drive system is evidently better than that of the single-drive system. In the experiment, under the condition of screw single drive and differential dual drive, the critical crawling velocities of the table are measured. The experimental results are consistent with the simulation results, which verifies that the established models are reasonable. This lays a foundation for the design and research of the controller.

Finite Element Analysis and Simulation of Al 7075 Alloy Joints Produced by Friction Stir Welding

2015 ◽  
Vol 766-767 ◽  
pp. 1116-1120
Author(s):  
R. Ramesh ◽  
S. Suresh Kumar ◽  
V. Sivaraman ◽  
R. Mohan
Keyword(s):  
Finite Element ◽  
Friction Stir Welding ◽  
Welding Speed ◽  
Axial Load ◽  
Maximum Temperature ◽  
Element Analysis ◽  
Friction Stir ◽  
Element Simulation ◽  
Al 7075 ◽  
7075 Alloy

The present work is mainly carried out to study the distribution of temperature in friction stir welded plate of Aluminium alloy. A 3-D finite element simulation model was developed to predict temperature distribution and residual stress in Friction Stir Welding (FSW) of Al 7075 alloy. The effect of angular velocity of tool, axial load and welding speed on the heat generated between the tool and plate to be welded was investigated. The simulations obtained were based on three factor five level central composite rotatable design. Second order polynomial equations for predicting the temperature was developed. Residual stresses for friction stir welded plates due to thermal cycles were predicted. The maximum temperature developed in friction stir welded plated increases with the increase of rotational speed of tool and axial load where as it decreases with increase in welding speed.

Experimental and Finite Element Modeling of Friction Stir Seal Welding of Tube-Tubesheet Joint

2012 ◽  
Vol 445 ◽  
pp. 771-776 ◽  
Author(s):  
Fadi Al-Badour ◽  
N. Merah ◽  
A.N. Shuaib ◽  
A. Bazoune
Keyword(s):  
Finite Element ◽  
Process Parameters ◽  
Axial Load ◽  
Solidus Temperature ◽  
Metal Flow ◽  
Material Model ◽  
Element Model ◽  
Fusion Welding ◽  
Maximum Temperature ◽  
Friction Stir

Tube-tubesheet joints are critical in some applications, where contact between shell and tube side fluids is not tolerable. To ensure joint tightness, standards (ASME and TEMA) recommend performing a combination of rolling-or expansion of tube-tubesheet and seal welding. Available techniques for seal welding are based on fusion welding that sometimes results in a number of defects such as cracking and porosity formation, and such defects may take a newly fabricated heat exchanger out of service. In this work, friction stir welding (FSW) was used for tube-tubesheet seal joint and simulated using a 3D thermo-mechanical finite element model (FEM). The model was analyzed using a commercial finite element (FE) package. The model included the thermal effect of the tool workpiece interaction along with axial load, ignoring the metal flow around the tool. The material model took into account temperature dependency of thermal and mechanical properties. The model objectives were to evaluate the temperature distribution and residual stress in the workpiece resulting from the thermal cycle and axial load during welding for various process parameters, and to study how residual stresses in adjacent roller expanded tubes are affected during welding. The FE results show that the maximum temperature at the welding zone does not exceed the solidus temperature (except at high tool rotational speeds); the process can thus be classified as cold working. Moreover, adjacent tubes temperature does not exceed the annealing temperature. An experimental setup was designed and manufactured to show the feasibility of the process in this constrained size joints and to validate the numerical results. A test cell and a special FSW tool were designed and manufactured for this purpose. Many tests were performed with welding quality depending on process parameters.

Study on the Relation between Bore Diameter of the Hollow Screw and Static Stiffness of the Dual-Drive System

2013 ◽  
Vol 401-403 ◽  
pp. 295-299
Author(s):  
Lan Jin ◽  
Bing Yan ◽  
Xiao Hui Zheng ◽  
Yong Wei Wang ◽  
Li Ming Xie
Keyword(s):  
Finite Element ◽  
Static Analysis ◽  
Parametric Design ◽  
Element Model ◽  
Drive System ◽  
Static Deformation ◽  
Machining Accuracy ◽  
Static Stiffness ◽  
Feed System ◽  
Shape And Size

The size of bore diameter of hollow screw, to some extent, will affect the dual-drive feed system's static stiffness, and then affect the machining accuracy of the workpiece. This paper takes the dual-drive feed system as the research object and builds its finite element model. Use the model to make static analysis in Workbench. After that, we can get the relation between bore diameter of hollow screw and static deformation of the dual-drive system. The results demonstrate that: with the bore diameter of hollow screw increases, the maximum static deformation volume of the dual-drive system gradually becomes larger. This article suggests that the appropriate design size of the diameter should be 4~10 mm. Because the corresponding static deformation of the dual-drive system changes little in magnitude within this range. These advised parameters can provide certain principles for the improvements of a hollow screw shape and size and its parametric design.

Effects of bottom plate in friction stir welding of AA6061-T6

2020 ◽  
Vol 118 (1) ◽  
pp. 108
Author(s):  
M.A. Vinayagamoorthi ◽  
M. Prince ◽  
S. Balasubramanian
Keyword(s):  
Mechanical Properties ◽  
Axial Load ◽  
Weld Zone ◽  
Welding Process ◽  
Bottom Plate ◽  
Welding Parameters ◽  
Nugget Zone ◽  
Friction Stir ◽  
Weld Joints ◽  
Fine Grain

The effects of 40 mm width bottom plates on the microstructural modifications and the mechanical properties of a 6 mm thick FSW AA6061-T6 joint have been investigated. The bottom plates are placed partially at the weld zone to absorb and dissipate heat during the welding process. An axial load of 5 to 7 kN, a rotational speed of 500 rpm, and a welding speed of 50 mm/min are employed as welding parameters. The size of the nugget zone (NZ) and heat-affected zone (HAZ) in the weld joints obtained from AISI 1040 steel bottom plate is more significant than that of weld joints obtained using copper bottom plate due to lower thermal conductivity of steel. Also, the weld joints obtained using copper bottom plate have fine grain microstructure due to the dynamic recrystallization. The friction stir welded joints obtained with copper bottom plate have exhibited higher ductility of 8.9% and higher tensile strength of 172 MPa as compared to the joints obtained using a steel bottom plate.

scholarly journals Improved design criterion for frictionally engaged contacts in overrunning clutches

2021 ◽  
Author(s):  
Nadine Nagler ◽  
Armin Lohrengel
Keyword(s):  
Design Process ◽  
Contact Area ◽  
Axial Load ◽  
State Of The Art ◽  
Tangential Force ◽  
Design Criterion ◽  
Hertzian Contact ◽  
Loss Of Function ◽  
Axial Loads ◽  
Improved Design

AbstractOverrunning clutches, also known as freewheel clutches, are frictionally engaged, directional clutches; they transmit torque depending on the Freewheel clutch rings’ rotation directions. The torque causes a tangential force in the Hertzian contact area. The hitherto “state-of-the-art design criterion” bases on this load situation. In practice, axial loads additionally act on the frictionally engaged Hertzian contact area. This additional axial load can cause the loss of the friction connection and so the freewheel clutch slips. This publication presents an improved design criterion for frictionally engaged contacts in freewheel clutches. It allows to consider tangential as well as axial loads during the design process. Additionally, it offers the possibility to estimate the probability of frictional engagement loss and gross slip based on the freewheel clutch’s application scenario. This publication points out how to use the improved design criterion to design freewheel clutches that are more robust against a loss of function.

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