scholarly journals Influence of Process Parameters on Forming Load of Variable-Section Thin-Walled Conical Parts in Spinning

2020 ◽  
Vol 10 (17) ◽  
pp. 5932
Author(s):  
Yingxiang Xia ◽  
Xuedao Shu ◽  
Ying Zhu ◽  
Zixuan Li
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Testing Machine ◽  
Feed Ratio ◽  
Forming Process ◽  
Influence Of Process Parameters ◽  
Forming Load ◽  
Variable Section ◽  
Thin Walled ◽  
Conical Casing

Thin-walled conical parts with variable-section are usually made of superalloy material, with poor plasticity and complex forces, which are difficult to form and control. In this research, a thin-walled conical casing of superalloy GH1140 with variable-section is studied; the real stress–strain curve of the material is fitted and the load-displacement curves of superalloy GH1140 are obtained through a universal testing machine. To clarify the equivalent stress distribution on the upper surface of the thin-walled casing during the forming process and after unloading the rotary wheel, the finite element model of the thin-walled conical casing during the spinning forming process is established with the Simufact Forming finite element analysis software. The effects of processing parameters, such as the mandrel rotational speed ω, the roller feed ratio f and the gap deviation rate δ between the roller and mandrel, on the spinning forming load were obtained. The distribution and numerical trend of the tangential residual stress after forming were detected by X-ray diffraction, and the causes of defects such as flange instability were analyzed. The results of the forming test and the test of residual stress conform well with the simulation, which verifies the stability of the model. The research provides a theoretical basis for improving the forming quality of thin-walled parts with variable-section.

scholarly journals Study on Residual Stress of Welded Hoop Structure

2020 ◽  
Vol 10 (8) ◽  
pp. 2838
Author(s):  
Wenbo Ma ◽  
Heng Zhang ◽  
Wei Zhu ◽  
Fu Xu ◽  
Caiqian Yang
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Welding Speed ◽  
Weld Seam ◽  
Outer Cylinder ◽  
Three Dimensional ◽  
Welding Residual Stress ◽  
Welding Parameters ◽  
Forming Process ◽  
Maximum Residual Stress

Residual stress is inevitable during welding, which will greatly affect the reliability of the structure. The purpose of this paper was to study the residual stress of the hoop structure caused by the cooling shrinkage of the weld when the outer cylinder was wrapped and welded under the condition of the existing inner cylinder. In this paper, the “method of killing activating elements” of ANSYS was used to simulate the three-dimensional finite element of the hoop structure. In the case of applying interlayer friction, the welding-forming process and welding circumferential residual stress of the hoop structure were analyzed. The blind hole method was used to test the residual stress distribution of the hoop structure, and the test results were compared with the finite element simulation results to verify the reliability of the simulation calculation method and the reliability of the calculation results. Then, the influence factors of the maximum welding residual stress of the hoop structure were studied. The results show that the maximum residual stress of the outer plate surface of the hoop structure decreases with the increase of the welding energy, the thickness of the laminate, the width of the weld seam, the welding speed, and the radius of the container. Based on the results of numerical simulation, the ternary first-order equations of the maximum residual stress of the hoop structure with respect to the welding speed, the thickness of the laminate, and the width of the weld seam were established. Then, the optimal welding parameters were obtained by optimizing the equations, which provided an important basis for the safe use and optimal design of the welding hoop structure.

Finite Element Analysis for Comprehensive Residual Stress of 7075 Aluminum Alloy Thick Plate

2010 ◽  
Vol 154-155 ◽  
pp. 1255-1261
Author(s):  
Hai Yan Li ◽  
Yi Du Zhang ◽  
Hong Wei Zhang
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Aluminum Alloy ◽  
Thick Plate ◽  
Coupling Effect ◽  
Element Model ◽  
Forming Process ◽  
Element Analysis ◽  
Field Coupling ◽  
Simulation And Experiment

Based on “physical field coupling” finite element method, the generation of residual stress and interactive coupling effect were analyzed during the forming process of aluminum alloy thick-plate. Therefore, comprehensive residual stress generated from rolling, quenching and stretching was obtained. The finite element model was proved effective by comparing the results of simulation and experiment. Results show that percent reduction has significant influence to the distribution and magnitude of rolling stress; There is a coupling effect between rolling stress and quenching stress, which represents a basic state; Furthermore, after stretching the distribution of coupling stress remains, but the value reduces greatly; The residual stress has got the minimum, when stretching is near 3%.

Influence of interlayer dwell time on stress field of thin-walled components in WAAM via numerical simulation and experimental tests

2019 ◽  
Vol 25 (8) ◽  
pp. 1433-1441 ◽  
Author(s):  
Rong Li ◽  
Jun Xiong
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Field ◽  
Ambient Temperature ◽  
Dwell Time ◽  
Stress Distributions ◽  
Widespread Application ◽  
Content Type ◽  
Longitudinal Residual Stress ◽  
Thin Walled

Purpose This paper aims to study the residual stress of deposited components which is a main issue to impede the widespread application of wire and arc additive manufacturing (WAAM). The interlayer dwell time is believed to have an effect on residual stress distributions in WAAM due to variance in heat dissipation condition. A coupled thermomechanical finite element model was established to evaluate the role of dwell time in between layers on the mechanical behavior of thin-walled components in WAAM, mainly involving thermal stress evolutions and residual stress distributions of the component and substrate. Design/methodology/approach Four interlayer dwell times including 0, 120 and 300 s and cooling to ambient temperature were selected in finite element modeling, and corresponding experiments were conducted to verify the reliability of the model. Findings The results show that with the interlayer dwell time, the stress cycling curves become more uniform and the interlayer stress-releasing effect is weakened. The residual stress levels on the substrate decrease with the increasing interlayer dwell time. In the outside surface of the component, the distributions of axial and longitudinal residual stress along the deposition path are the smoothest when the interlayer dwell time is cooling to ambient temperature. In the inside surface, a longer interlayer dwell time leads to an obvious decrease in the longitudinal and axial residual stress along the deposition path. Originality/value The comprehensive study of how the interlayer dwell time influences stress field of components is helpful to improve the deposition defects generated by WAAM.

Law of Metal Flow of Thin-Walled Conical Part With Variable Section During Spinning

2020 ◽  
Author(s):  
Shu Xuedao ◽  
Xia Yingxiang ◽  
Zhu Ying ◽  
Li Zixuan ◽  
Ye Bohai
Keyword(s):  
Metal Flow ◽  
Conical Part ◽  
Forming Process ◽  
Finite Element Software ◽  
Axial Tensile ◽  
Variable Section ◽  
Spinning Process ◽  
Thin Walled ◽  
Forming Defects

Abstract During the spinning process of the variable-section thin-walled conical parts, the metal flow law is relatively complicated and the flange is prone to be unstable, which resulting in wrinkling and other defects. In this paper, the variable-section conical part of superalloy GH1140 is taken as the research object. The spinning forming process is numerically simulated by using Simufact Finite Element software and the metal flow in each stage of the forming process is analyzed. The flow velocity shows an annular distribution as a whole. The metal near the center of the circle flows more slowly, and the metal far from the circular flange flows more quickly. In the direction of thickness, the velocity of metal flow decreases gradually. Under the feeding action of the roller, the metal in front of the roller is subjected to axial tensile stress, tangential and radial compressive stress, resulting in a strain state of one-way tension and two-way compression. The metal moves along the negative direction of the rotary wheel feed, resulting in the increase of the sheet wall thickness. The correctness of the model in this paper is further verified by spinning experiments. The research results provide a theoretical basis for analyzing the mechanism of forming defects and improving the quality of spinning forming of conical thin-walled parts with variable sections.

Influence of Process Parameters on Electric Upsetting Process by Using Finite Element Modeling

2017 ◽  
Vol 728 ◽  
pp. 42-47 ◽  
Author(s):  
Pattarapong Nuasri ◽  
Yingyot Aue-u-Lan
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Material Flow ◽  
Electric Heating ◽  
Heating System ◽  
Forming Process ◽  
Influence Of Process Parameters ◽  
Element Modeling ◽  
Electric Upsetting ◽  
The Relationship

Electric Upsetting Process (EUP) is a process combining the forming process with the electric heating system. It is commonly used to manufacture a preform of a bar with high upsetting ratio, such as an axial shaft. The reliable forming process requires the understanding the effect of process and electrical parameters. Currently, the designer develops this process by trail-and-error. To successfully develop this process, the relationship between the electric heating and the forming parameters needs to be clearly understood. In this study, three parameters are investigated; namely anvil speed, upsetting load and heating voltage. Finite Element Modeling (FEM) is used as a tool for evaluating these parameters. The FEM results indicate that those parameters play significant roles on the material flow as well as the heating characteristics (i.e. temperature distributions and heat flow).

Effect of Residual Forming Stresses on Fracture in ERW Pipe

2016 ◽  
Author(s):  
Ted L. Anderson ◽  
Gregory W. Brown
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Fracture Behavior ◽  
Finite Element Simulations ◽  
Finite Element Analyses ◽  
Forming Process ◽  
Cold Expansion ◽  
The Past

Many older pipelines contain significant residual stress due to the forming process. Cold expansion or a normalizing heat treatment can virtually eliminate residual forming stresses, but these practices were less common in the past. In the absence of cold expansion or normalization, residual forming stresses can be reduced by hydrostatic testing or operating pressures, but not eliminated entirely. Residual stresses can contribute to fracture in pipelines, particularly when the material toughness is low. This article presents a series of analyses that seek to quantify the magnitude of residual forming stresses as well as their impact on pipeline integrity. The pipe forming process was simulated with elastic-plastic finite element analyses, which considered the effect of subsequent loading on relaxation of residual stresses. A second set of finite element simulations were used to quantify the effect of residual stresses on fracture behavior.

scholarly journals Modeling the behavior of thin-walled tubes with different fillers at the maximum load in solving the problems of crashworthiness

2019 ◽  
Author(s):  
R.B. Goncharov ◽  
V.N. Zuzov ◽  
D.N. Chaiko
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Aluminum Alloy ◽  
Epoxy Resin ◽  
Aluminum Foam ◽  
Testing Machine ◽  
Elastoplastic Material ◽  
Filler Materials ◽  
Bending Load ◽  
Thin Walled

The article considers issues related to the choice of effective finite-element modeling thin-walled tubes with different types of fillers (imitating elements of car bodies and cabs of frame-type cars) with quasi-static bending load, causing the tube and filler to collapse, in the context of optimal design. Thin-walled pipes made of aluminum alloy AMg6 with aluminum foam fillers; epoxy resin and composite (consisting of Poraver balls and epoxy resin) were the subject of the study. Aluminum foam is an elastoplastic material; it is one of the best fillers for solving the problems of crashworthiness, although it requires expensive technological equipment for filling. Epoxy resin is a fragile material, but inexpensive, affordable and technologically “convenient”. In addition to the influence of the filler on the tube mechanical properties the effects of the constrained behavior of the filler material under the ultimate bending loading of the tube are investigated. To verify the theoretical assumptions, tests were performed on the Zwick Z100 universal testing machine (for a hollow thin-walled tube made of aluminum alloy and similar tubes with fillers). Here there are the results of numerical computations and the results of the experiment (the error of calculations does not exceed 8 %). The most rational material in terms of energy-mass ratio is aluminum foam (with an increase in sample mass of 2.1 times the mechanical properties increased tenfold). Other fillers give much worse results for the same parameters. Using the proposed finite element models (FEM), allows assessment of the effectiveness of existing and being created filler materials for refining the car bodies and cabs according to the requirements of crashworthiness

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