scholarly journals Spring-Back Prediction of the Bi-Layered Metallic Tube under CNC Bending Considering Neutral Layer Shifting Extraction

2020 ◽  
Vol 10 (14) ◽  
pp. 4978
Author(s):  
Shuyou Zhang ◽  
Mengyu Fu ◽  
Zili Wang ◽  
Yaochen Lin ◽  
Ci He
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Prediction Model ◽  
Extreme Environments ◽  
Internal Force ◽  
Spring Back ◽  
Neutral Layer ◽  
Composite Strain ◽  
Back Angle ◽  
Theoretical Results

Bi-layered metallic bending tubes are widely used in extreme environments. The spring-back prediction theory for precise forming of such tube configuration is lacking. The layered coupling causes complex section internal force and new boundary conditions. This work proposed a theoretical prediction model of bimetallic tubes’ spring-back under computer numerically controlled (CNC) bending. This model calculated the spring-back angle by importing two new parameters—the composite elastic modulus (Ec) and the composite strain neutral layer (Dε). To investigate Dε, the neutral layer shifting extraction method was proposed to get the shifting value from finite element simulations. Simulations and full-scale bending experiments were carried out to verify the reliability of this prediction model. The theoretical results are closer to the experimental results than the finite element (FE) results and the theoretical results neglecting neutral layer shifting. The change of spring-back angle with the interlaminar friction coefficient was investigated. The results indicated that the normal mechanical bonding bimetallic tube with an interlaminar friction coefficient below 0.3 can reduce spring-back.

Torque capacity of the multilayer interference fit based on a friction coefficient prediction model

2021 ◽  
pp. 135065012110397
Author(s):  
Ke Ning ◽  
Jianmei Wang ◽  
Dan Xiang ◽  
Dingbang Hou
Keyword(s):  
Finite Element ◽  
Theoretical Model ◽  
Friction Coefficient ◽  
Prediction Model ◽  
Three Dimensional ◽  
Element Model ◽  
Maximum Relative Error ◽  
Interference Fit ◽  
Mathematical Expressions ◽  
Torque Capacity

This paper proposes the theoretical model of a multilayer interference fit and gives out the relational expression between radial interference and friction coefficient. Taking the typical wind turbine's shrink disk of a three-layer interference fit structure as an example, special experimental equipment is developed to test the torque capacity. Based on experimental results and the theoretical model, the mathematical expressions of radial interference and assembly stroke for friction coefficient are obtained by polynomial fitting, and the prediction model of friction coefficient is established. The three-dimensional finite element model of a shrink disk is constructed by applying the friction coefficient prediction model. With the mathematical expressions of radial interference and assembly stroke for the torque capacity, the rules of main dimension parameters and torque capacity are analyzed. The maximum relative error between experiment and simulation is 8.2%, which shows the feasibility of finite element simulation. The results of our study have certain guidance for the prediction of friction coefficient and the manufacture of the multilayer interference fit.

Study on Spring-Back of CU11000 Clad AL1050 Sheets

2014 ◽  
Vol 941-944 ◽  
pp. 1688-1691
Author(s):  
Shou Fa Liu ◽  
Fei Xue ◽  
Song Lin Wu
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Spring Back ◽  
Bend Radius ◽  
Cu Content ◽  
Element Simulation ◽  
Bending Process ◽  
Clad Metals ◽  
Simulation And Experiment ◽  
Back Angle

This study is aimed to investigate the spring-back angle of clad metal sheet in bending process by using finite element simulation and experiment to meet the growing requires in the application of clad metals. In this study, the clad metals processed into 1mm thick from CU11000 and AL1050 were bent 90o over a die with a bend radius of 1mm. The results show that there is not any relative sliding, crushing or peeling occurred in the junction of the clad material during the bending process, the spring-back angle of the clad metal is always smaller than each single metal and the CU content increasing also caused spring-back angle become small. The configuration of a harder material (CU11000) in tensile side also has a smaller spring-back angle.

A Study of Transmission Error Modeling and Preload Compensation for the Cable-Driven Sheaves Used in Space Docking Locks

2020 ◽  
Vol 36 (6) ◽  
pp. N9-N20
Author(s):  
Chuntian Xu ◽  
Jianguang Li ◽  
Peng Wang ◽  
Zhengdong Xu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Friction Coefficient ◽  
Prediction Model ◽  
Transmission Error ◽  
Error Modeling ◽  
Operating Conditions ◽  
Element Analysis ◽  
Proposed Model ◽  
Testing Efficiency

ABSTRACTThe transmission error of cable-driven sheaves (CDS) used in space docking locks directly affects the synchronous docking of two spacecraft, which is guaranteed mainly by the preload applied to their serial cables. But it is difficult controlled precisely because of the complicated cable deformation and operating conditions. The synchronous testing efficiency of the docking locks is inevitably influenced, correspondingly. This paper proposes a prediction model for the transmission error of CDS based on their cable deformation. In this model, the deformations of non- and free sectional cables are both modified on finite element analysis, which are respectively derived from classical Capstan equation and Hooke’s law for them without considering the effects of the friction coefficient between wire strands. Based on the proposed model, the relationships between the transmission error and dominating factors are analyzed. Then the preload compensation for transmission error is obtained at the engaging and locking angles of the docking locks, respectively. Experiments validate the model. This can provide a valuable reference in controlling the transmission error of CDS and improving the assembly efficiency of docking locks.

Influence of the contact with friction on the deformation behavior of advanced high strength steels in the Nakajima test

2021 ◽  
pp. 030932472110212
Author(s):  
Mohammad Mehdi Kasaei ◽  
Marta C Oliveira
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Strain Rate ◽  
Contact Pressure ◽  
Deformation Behaviour ◽  
High Strength Steels ◽  
High Strength ◽  
Advanced High Strength Steels ◽  
Deformation Mechanics ◽  
Nakajima Test

This work presents a new understanding on the deformation mechanics involved in the Nakajima test, which is commonly used to determine the forming limit curve of sheet metals, and is focused on the interaction between the friction conditions and the deformation behaviour of a dual phase steel. The methodology is based on the finite element analysis of the Nakajima test, considering different values of the classic Coulomb friction coefficient, including a pressure-dependent model. The validity of the finite element model is examined through a comparison with experimental data. The results show that friction affects the location and strain path of the necking point by changing the strain rate distribution in the specimen. The strain localization alters the contact status from slip to stick at a portion of the contact area from the pole to the necking zone. This leads to the sharp increase of the strain rate at the necking point, as the punch rises further. The influence of the pressure-dependent friction coefficient on the deformation behaviour is very small, due to the uniform distribution of the contact pressure in the Nakajima test. Moreover, the low contact pressure range attained cannot properly replicate real contact condition in sheet metal forming processes of advanced high strength steels.

Structure-Soil Interaction of Buried Corrugated Steel Arch Bridge

2010 ◽  
Vol 163-167 ◽  
pp. 2112-2117
Author(s):  
Miao Xin Zhang ◽  
Bao Dong Liu ◽  
Peng Fei Li ◽  
Zhi Mao Feng
Keyword(s):  
Finite Element ◽  
Steel Structures ◽  
Internal Force ◽  
Structural Deformation ◽  
Fe Model ◽  
Soil Pressure ◽  
Load Range ◽  
Finite Element Program ◽  
Load Conditions ◽  
Peak Value

Corrugated steel plate and surrounding soils are working together to share the load in buried corrugated steel structures. It is complicated to consider the structure-soil interaction, so the finite element method has already become the chief means of complicated structure analysis. Based on a practical project, considering structure-soil interaction, by using the finite element program of ANSYS, the paper set up a 2-D FE model and analyzed the soil pressure, the structural deformation and the internal force under different load conditions in detail. The analysis shows that structure-soil interaction has brought about stresses redistribution of surrounding soils, and adverse effects of soil pressure and displacement were limited. The variation range of soil pressure on the crown of arch increases with the load increases and the peak value of soil pressure approach to the code value and a rebound appears in the vehicle load range. The tendencies of vertical soil displacement are nearly the same to different load conditions, and the peak value of moments has an obvious change and can be influenced greatly by deflective load.

3D Coupled Thermomechanical Finite Element Analysis of Ultrasonic Consolidation

2007 ◽  
Vol 539-543 ◽  
pp. 2651-2656 ◽  
Author(s):  
C.J. Huang ◽  
E. Ghassemieh
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Friction Coefficient ◽  
Stress Field ◽  
Ultrasonic Wave ◽  
Ultrasonic Vibration ◽  
Softening Effect ◽  
Element Analysis ◽  
Consolidation Process ◽  
Ultrasonic Consolidation

A 3-D coupled temperature-displacement finite element analysis is performed to study an ultrasonic consolidation process. Results show that ultrasonic wave is effective in causing deformation in aluminum foils. Ultrasonic vibration leads to an oscillating stress field. The oscillation of stress in substrate lags behind the ultrasonic vibration by about 0.1 cycle of ultrasonic wave. The upper foil, which is in contact with the substrate, has the most severe deformation. The substrate undergoes little deformation. Apparent material softening by ultrasonic wave, which is of great concern for decades, is successfully simulated. The higher the friction coefficient, the more obvious the apparent material softening effect.

Research on Surface Roughness of Supersonic Vibration Auxiliary Side Milling for Titanium Alloy

2021 ◽  
Author(s):  
XueTao Wei ◽  
caixue yue ◽  
DeSheng Hu ◽  
XianLi Liu ◽  
YunPeng Ding ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Finite Element ◽  
Prediction Model ◽  
Simulation Model ◽  
Finite Element Simulation ◽  
Simulation Software ◽  
Surface Roughness Prediction ◽  
Contour Shape ◽  
Element Simulation ◽  
Roughness Prediction

Abstract The processed surface contour shape is extracted with the finite element simulation software, and the difference value of contour shape change is used as the parameters of balancing surface roughness to construct the infinitesimal element cutting finite element model of supersonic vibration milling in cutting stability domain. The surface roughness trial scheme is designed in the central composite test design method to analyze the surface roughness test result in the response surface methodology. The surface roughness prediction model is established and optimized. Finally, the finite element simulation model and surface roughness prediction model are verified and analyzed through experiment. The research results show that, compared with the experiment results, the maximum error of finite element simulation model and surface roughness prediction model is 30.9% and12.3%, respectively. So, the model in this paper is accurate and will provide the theoretical basis for optimization study of auxiliary milling process of supersonic vibration.

scholarly journals The inf-sup stability of the lowest order Taylor–Hood pair on affine anisotropic meshes

2019 ◽  
Vol 40 (4) ◽  
pp. 2377-2398
Author(s):  
Gabriel R Barrenechea ◽  
Andreas Wachtel
Keyword(s):  
Finite Element ◽  
Fluid Mechanics ◽  
Incompressible Fluid ◽  
Stokes Equations ◽  
Sufficient Conditions ◽  
Navier Stokes ◽  
Element Solution ◽  
Navier Stokes Equations ◽  
Anisotropic Meshes ◽  
Theoretical Results

Abstract Uniform inf-sup conditions are of fundamental importance for the finite element solution of problems in incompressible fluid mechanics, such as the Stokes and Navier–Stokes equations. In this work we prove a uniform inf-sup condition for the lowest-order Taylor–Hood pairs $\mathbb{Q}_2\times \mathbb{Q}_1$ and $\mathbb{P}_2\times \mathbb{P}_1$ on a family of affine anisotropic meshes. These meshes may contain refined edge and corner patches. We identify necessary hypotheses for edge patches to allow uniform stability and sufficient conditions for corner patches. For the proof, we generalize Verfürth’s trick and recent results by some of the authors. Numerical evidence confirms the theoretical results.

scholarly journals Relationship Between Rockwell C Hardness and Inelastic Material Constants

2002 ◽  
Vol 124 (2) ◽  
pp. 179-184 ◽  
Author(s):  
Akihiko Hirano ◽  
Masao Sakane ◽  
Naomi Hamada
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Strain Hardening ◽  
Yield Stress ◽  
Plastic Material ◽  
Stress And Strain ◽  
Material Constants ◽  
Elastic Plastic ◽  
Elastic Plastic Material ◽  
Hardening Coefficient

This paper describes the relationship between Rockwell C hardness and elastic-plastic material constants by using finite element analyses. Finite element Rockwell C hardness analyses were carried out to study the effects of friction coefficient and elastic-plastic material constants on the hardness. The friction coefficient and Young’s modulus had no influence on the hardness but the inelastic materials constants, yield stress, and strain hardening coefficient and exponent, had a significant influence on the hardness. A new equation for predicting the hardness was proposed as a function of yield stress and strain hardening coefficient and exponent. The equation evaluated the hardness within a ±5% difference for all the finite element and experimental results. The critical thickness of specimen and critical distance from specimen edge in the hardness testing was also discussed in connection with JIS and ISO standards.

Research on Stamping Spring-Back Prediction for Car Body Panel Based on BP Neural Network

2010 ◽  
Vol 97-101 ◽  
pp. 250-254 ◽  
Author(s):  
Xin Jian Zhou
Keyword(s):  
Neural Network ◽  
Prediction Model ◽  
Bp Neural Network ◽  
Front Panel ◽  
Spring Back ◽  
Test Analysis ◽  
Car Body ◽  
Neural Network Prediction ◽  
Mould Design ◽  
Bp Neural Network Model

On the basis of orthogonal test analysis of variance, BP neural network is used to forecast quantitatively the stamping spring-back of front panel of a car body, namely the engine hood, under the conditions of different stamping parameters. Firstly, BP neural network prediction model is established and sample training is done in Matlab. Then, the spring-back prediction using BP neural network and the result of spring-back simulation using Dynaform is compared to verify the precision and stability of the prediction model. Lastly, modification is made to the BP neural network according to practical stamping parameters and an efficient BP neural network model is established. Using this model, stamping spring-back prediction for the front panel of a car body is made. The spring-back prediction could then be used for spring-back compensation in the mould design of the front panel.

Sign in / Sign up

Export Citation Format

Share Document