Numerical investigation of effects of deformation allocation on multi-pass conventional spinning process of curvilinear generatrix parts

2015 ◽  
Vol 229 (18) ◽  
pp. 3299-3307
Author(s):  
Xiao-Jun Lin ◽  
Ting Ge ◽  
Jin Wang ◽  
Guo-Dong Lu
Keyword(s):  
Thickness Distribution ◽  
Element Model ◽  
Deformation Pattern ◽  
Axial Distance ◽  
Arc Length ◽  
Forming Quality ◽  
Wall Thickness Distribution ◽  
Spinning Process ◽  
Conventional Spinning ◽  
Forming Efficiency

Deformation allocation has significant effects on the process of multi-pass conventional spinning, especially for the curvilinear generatrix parts. Three different patterns of deformation allocation for curvilinear generatrix parts, including equal max deformation, equal arc length, and equal axial distance, are proposed and defined. Roller path profiles are designed based on them respectively. A 3D elastic-plastic finite element model is developed to investigate the effects of deformation allocation on forming quality and efficiency of the multi-pass spinning of curvilinear generatrix parts, based on the designed paths. The results show that a reasonable deformation allocation in each pass can improve the efficiency of the process effectively. The equal max deformation pattern can lead to better wall thickness distribution and forming efficiency. However, the fittability of it is poorer, compared with the others. This phenomenon is more significant with the increase of pass number.

Numerical and Experimental Analysis of Attaching-Mandrel Process Under Multi-Pass Cold Spinning Process on Superalloy GH3030

2019 ◽  
Author(s):  
Li Zixuan ◽  
Shu Xuedao ◽  
Cen Zewei ◽  
Zhang Song
Keyword(s):  
Production Efficiency ◽  
Thickness Distribution ◽  
Grain Structure ◽  
Combination Method ◽  
Nickel Base Superalloy ◽  
Forming Quality ◽  
Spinning Process ◽  
Conventional Spinning ◽  
Hot Spinning Process ◽  
Nickel Base

Abstract The superalloy products formed by multi-pass conventional spinning are widely used in rotary forming parts with complex shapes. As the connection of each forming pass, the attaching-mandrel process has an important influence on forming quality and production efficiency. The hot spinning process is usually adopted in superalloy forming because its poor plasticity in normal temperature, meanwhile, it brings the poor surface quality of the parts and huge energy consumption. For this reason, the cold spinning and the attaching-mandrel process of nickel-base superalloy GH3030 are studied. The combination method of experiment and simulation is used to study the attaching-mandrel process based on one-forward-pass spinning process. The effects of pass pitch and the attaching-mandrel velocity on the tool forces, parts stress field, strain field and wall thickness distribution are analyzed. The microstructure of the part is divided into three layers: outer, middle and inner layer. The grain size of each layer is compared. Then the effect of different pass pitch on the grain structure is clarified. The results show that the reasonable pass pitch and the attaching-mandrel velocity can improve the forming quality and production efficiency. The multi-pass cold spinning process on superalloy GH3030 is feasible. The excessive pass pitch can cause seriously grain elongation, the grain boundaries are blurred, and even cracking.

Three Dimension Finite Element Model for Neck-Spinning Process of Tube at Elevated Temperature

2011 ◽  
Vol 110-116 ◽  
pp. 2708-2716
Author(s):  
Ching Hua Huang ◽  
Ching Hua Hung ◽  
Jung Chung Hung ◽  
Chia Rung Lin
Keyword(s):  
Elevated Temperature ◽  
Thickness Distribution ◽  
Shell Element ◽  
Element Model ◽  
Scaling Factor ◽  
Strain Rates ◽  
Three Dimension ◽  
Mass Scaling ◽  
Spinning Process ◽  
Simulation Results

The aim of this research is to investigate numerically the neck-spinning process of a tube at elevated temperature. The commercial software Abaqus/Explicit was adopted in the simulation. For the construction of the material model, special uni-axial tensile tests were conducted at elevated temperature and various strain rates, since the material is sensitive to strain rates at high temperature. The influence of the element type and mass scaling factor were investigated through numerical simulation. Full-integration shell element is the better choice in the simulation of the neck-spinning process at elevated temperature. The use of suitable mass scaling factor will make the analysis more efficiency. Comparisons between experimental and simulation results on thickness distribution and the outer contour of the spun tube are discussed. Good agreement was found between experimental and simulation results.

The Influence of the Roller Forming Path on the Neck-Spinning Process of Tube at Elevated Temperature

2011 ◽  
Author(s):  
Chi-Chen Huang ◽  
Jung-Chung Hung ◽  
Cheng-Chan Lo ◽  
Chia-Rung Lin ◽  
Chinghua Hung
Keyword(s):  
Finite Element ◽  
Elevated Temperature ◽  
Elevated Temperatures ◽  
Thickness Distribution ◽  
Optimization Technique ◽  
Element Model ◽  
Strain Rates ◽  
Forming Process ◽  
Tube Spinning ◽  
Spinning Process

The tube spinning process is a metal forming process used in the manufacture of axisymmetric products, and has been widely used in various applications. In this paper, the neck-spinning process was applied to form the neck part of the tube end at an elevated temperature. The spun tube was used as a high pressure CO2 vessel, which is a component of motorcycle airbag jackets. An uneven surface will occur on the tube surface if the thickness distribution of the tube is not uniform after the neck-spinning process. This is because different thicknesses result from different contractions during the cooling stage. For this reason, the aim of this research was to numerically investigate the roller forming path to improve the thickness distribution of the tube during the neck-spinning process. The finite element method was used to simulate the neck-spinning process of the tube at an elevated temperature. For the construction of the material model, special uni-axial tensile tests were conducted at elevated temperatures and various strain rates, because the material is sensitive to strain rates at high temperatures. This paper compares the experimental and simulation results of the thickness distribution and the outer contour of the spun tube. The validated finite element model was used to investigate the influence of the roller forming path on the thickness distribution of the tube. The thickness distribution of the tube formed by a curved path was found to be more uniform than for the tube formed by a straight path. Finally, the optimization technique was used to find the optimal forming path, and the optimal result was verified experimentally.

Wall Thickness Distribution during a Combined Tube Spinning and Bending Process

2015 ◽  
Vol 651-653 ◽  
pp. 1614-1619 ◽  
Author(s):  
Chrstioph Becker ◽  
A. Erman Tekkaya
Keyword(s):  
Wall Thickness ◽  
Thickness Distribution ◽  
Tube Bending ◽  
Tube Spinning ◽  
Wall Thickness Distribution ◽  
Wall Thinning ◽  
Bending Process ◽  
Spinning Process ◽  
Process Combination

During a tube bending process the wall thickness distribution plays an important role concerning the process limits. Especially the wall thinning at the extrados of the tube is crucial. The wall thickness in a combined tube bending and tube spinning process will be analyzed. Therefore, possible stages of complexity are presented to show the possibilities of such a process combination. Based on this the interactions between the bending and spinning process on the wall thickness distribution will be discussed. Finally, a diagram will show how to adjust the wall thickness at the extrados of the tube only by adapting the tube spinning process.

Influence of the Different Combination of Diameters of Two Tool Heads on Forming Quality in Double Sided Incremental Forming

2021 ◽  
Vol 904 ◽  
pp. 20-25
Author(s):  
Xian Rui Wang ◽  
Hu Zhu ◽  
Dong Won Jung
Keyword(s):  
Incremental Forming ◽  
Thickness Distribution ◽  
Forming Quality ◽  
Forming Efficiency ◽  
Formed Part ◽  
Lower Tool ◽  
Different Diameters

The existing double sided incremental forming (DSIF) mostly uses two tools with the same diameter as the upper/lower tools, which is not conducive to improve the forming quality and forming efficiency. In this paper, the influence of the different combination of the upper and lower tool head diameters on the thickness distribution and the contour dimension accuracy of the formed part is studied by using ANSYS / LS-DYNA software and by taking the model with bidirectional convex features as the research object. It is found that the reasonable combination of different diameters of the upper/lower tools based on the characteristics of the parts to be formed can improve the forming quality and forming efficiency.

scholarly journals Finite-Element Modelling of Double-Roller Clamping Spinning of Wind Concentrator

2022 ◽  
Vol 9 ◽  
Author(s):  
Xueyong Qu ◽  
Hongzhong Xu ◽  
Shuqin Fan ◽  
Xiaole Cheng ◽  
Shengdun Zhao ◽  
...  
Keyword(s):  
Finite Element ◽  
Complex Shape ◽  
Thickness Distribution ◽  
Fe Analysis ◽  
Fe Model ◽  
Analysis Model ◽  
Forming Process ◽  
Wall Thickness Distribution ◽  
Plastic Deformation Behavior ◽  
Spinning Process

In order to improve the unit-power of a wind-driven generator, a wind concentrator with complex shape is installed in front of the impeller, which makes the airflow integrated and accelerated. It is important to manufacture the wind concentrator with high precision. The double-roller clamping spinning (DRCS) is a dieless, flexible spinning process that is very suitable for forming a wind concentrator with complex shape. The profile of a wind concentrator is divided into two parts: the contraction section and the expanding section. The process routes of both the contraction section and the expanding section are determined, and roller path equations are derived. Then the finite element (FE) analysis model that can describe the plastic deformation behavior of the DRCS forming for a wind concentrator is established, and the DRCS process of the flange is simulated. Furthermore, the wall-thickness distribution on the expanding section during the forming process is obtained. Finally, the reliability of the FE model is verified using the experimental results.

scholarly journals Effects of intracorneal ring segments implementation technique and design on corneal biomechanics and keratometry in a personalized computational analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Niksa Mohammadi Bagheri ◽  
Mahmoud Kadkhodaei ◽  
Shiva Pirhadi ◽  
Peiman Mosaddegh
Keyword(s):  
Clinical Data ◽  
Three Dimensional ◽  
Element Model ◽  
Von Mises Stress ◽  
Patient Specific ◽  
Average Error ◽  
Constant Thickness ◽  
Arc Length ◽  
Implementation Techniques ◽  
Von Mises

AbstractThe implementation of intracorneal ring segments (ICRS) is one of the successfully applied refractive operations for the treatment of keratoconus (kc) progression. The different selection of ICRS types along with the surgical implementation techniques can significantly affect surgical outcomes. Thus, this study aimed to investigate the influence of ICRS implementation techniques and design on the postoperative biomechanical state and keratometry results. The clinical data of three patients with different stages and patterns of keratoconus were assessed to develop a three-dimensional (3D) patient-specific finite-element model (FEM) of the keratoconic cornea. For each patient, the exact surgery procedure definitions were interpreted in the step-by-step FEM. Then, seven surgical scenarios, including different ICRS designs (complete and incomplete segment), with two surgical implementation methods (tunnel incision and lamellar pocket cut), were simulated. The pre- and postoperative predicted results of FEM were validated with the corresponding clinical data. For the pre- and postoperative results, the average error of 0.4% and 3.7% for the mean keratometry value ($$\text {K}_{\text{mean}}$$ K mean ) were predicted. Furthermore, the difference in induced flattening effects was negligible for three ICRS types (KeraRing segment with arc-length of 355, 320, and two separate 160) of equal thickness. In contrast, the single and double progressive thickness of KeraRing 160 caused a significantly lower flattening effect compared to the same type with constant thickness. The observations indicated that the greater the segment thickness and arc-length, the lower the induced mean keratometry values. While the application of the tunnel incision method resulted in a lower $$\text {K}_{\text{mean}}$$ K mean value for moderate and advanced KC, the induced maximum Von Mises stress on the postoperative cornea exceeded the induced maximum stress on the cornea more than two to five times compared to the pocket incision and the preoperative state of the cornea. In particular, an asymmetric regional Von Mises stress on the corneal surface was generated with a progressive ICRS thickness. These findings could be an early biomechanical sign for a later corneal instability and ICRS migration. The developed methodology provided a platform to personalize ICRS refractive surgery with regard to the patient’s keratoconus stage in order to facilitate the efficiency and biomechanical stability of the surgery.

scholarly journals Analysis of Contact Mechanical Characteristics of Flexible Parts in Harmonic Gear Reducer

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Fanjie Li ◽  
Xiaopeng Li ◽  
Yajing Guo ◽  
Dongyang Shang
Keyword(s):  
Mechanical Characteristics ◽  
Angular Displacement ◽  
Excitation Frequency ◽  
Element Model ◽  
Industrial Robots ◽  
Axial Distance ◽  
Axial Vibration ◽  
Cylinder Length ◽  
Flexible Parts ◽  
Contact Mechanical

Harmonic gear reducer is widely used in industrial robots, aerospace, optics, and other high-end fields. The failure of harmonic gear reducer is mainly caused by the damage of flexible bearing and flexspline of thin-walled vulnerable components. To study the contact mechanical characteristics of flexible components such as flexible bearing and flexspline in harmonic gear reducer, the contact mechanical model of flexible bearing, vibration differential equation of flexspline, and finite element model of each component in harmonic gear reducer were established. Based on the established model of harmonic gear reducer, the influence of the length of flexspline cylinder and the thickness of cylinder bottom on the stress of flexspline is discussed, respectively, and the motion characteristics of flexible bearing are studied. At the same time, the spatial distribution of the displacement of the flexspline and the axial vibration response of the flexspline are studied. The correctness of the model established in this paper is verified by experiments. The results show that the increase of cylinder length can improve the stress of flexspline in harmonic gear reducer; the wall thickness of cylinder bottom mainly affects the stress at the bottom of flexspline but has little effect on the stress of gear ring and smooth cylinder. Along the axis direction of the flexspline, the radial displacement, circumferential displacement, and angular displacement increase linearly with the increase of the axial distance between the cylinder and the bottom. When the excitation frequency is high, the vibration mode of flexspline shell is mainly axial vibration. The research results will provide a theoretical reference for the optimal design of harmonic gear reducer and improving the service life of flexible parts.

Sign in / Sign up

Export Citation Format

Share Document