scholarly journals Development of finite element models of gas forming process of Ti alloys structures

2021 ◽  
Vol 266 ◽  
pp. 09004
Author(s):  
K.J. Savinkova ◽  
Ya.A. Sobolev

The use of combined technology of gas forming and solid-phase pressure bonding for manufacturing large-diameter torus billets with diameter up to 1500 mm, wall thickness up to 8 mm, and diameter in cross-section up to 400 mm from titanium alloys for manufacturing of pipeline bends of desired size is shown. The technologymaes it possible to reduce production costs by increasing the productivity of the manufacturing process and applying new design and technological solutions. The possibility of using the SIMULIA Abaqus software package for modeling gas forming of titanium alloys in superplasticityconditions with non-uniform heating of the billets is considered. The method of combined thermo mechanical analysis (COUPLED TEMP-DISPLACEMENT) with inclusion of the creep effect was used.

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6372
Author(s):  
Valentin Oleksik ◽  
Tomasz Trzepieciński ◽  
Marcin Szpunar ◽  
Łukasz Chodoła ◽  
Daniel Ficek ◽  
...  

Incremental sheet forming of titanium and its alloys has a significant role in modern manufacturing techniques because it allows for the production of high-quality products with complex shapes at low production costs. Stamping processes are a major contributor to plastic working techniques in industries such as automotive, aerospace and medicine. This article reviews the development of the single-point incremental forming (SPIF) technique in titanium and its alloys. Problems of a tribological and microstructural nature that make it difficult to obtain components with the desired geometric and shape accuracy are discussed. Great emphasis is placed on current trends in SPIF of difficult-to-form α-, α + β- and β-type titanium alloys. Potential uses of SPIF for forming products in various industries are also indicated, with a particular focus on medical applications. The conclusions of the review provide a structured guideline for scientists and practitioners working on incremental forming of titanium and titanium alloy sheets. One of the ways to increase the formability and minimize the springback of titanium alloys is to treat them at elevated temperatures. The main approaches developed for introducing temperature into a workpiece are friction heating, electrical heating and laser heating. The selection of an appropriate lubricant is a key aspect of the forming process of titanium and its alloys, which exhibit unfavorable tribological properties such as high adhesion and a tendency to adhesive wear. A review of the literature showed that there are insufficient investigations into the synergistic effect of rotational speed and tool rotation direction on the surface roughness of workpieces.


Author(s):  
N. E. Paton ◽  
D. de Fontaine ◽  
J. C. Williams

The electron microscope has been used to study the diffusionless β → β + ω transformation occurring in certain titanium alloys at low temperatures. Evidence for such a transformation was obtained by Cometto et al by means of x-ray diffraction and resistivity measurements on a Ti-Nb alloy. The present work shows that this type of transformation can occur in several Ti alloys of suitable composition, and some of the details of the transformation are elucidated by means of direct observation in the electron microscope.Thin foils were examined in a Philips EM-300 electron microscope equipped with a uniaxial tilt, liquid nitrogen cooled, cold stage and a high resolution dark field device. Selected area electron diffraction was used to identify the phases present and the ω-phase was imaged in dark field by using a (101)ω reflection. Alloys were water quenched from 950°C, thinned, and mounted between copper grids to minimize temperature gradients in the foil.


2014 ◽  
Vol 997 ◽  
pp. 517-521
Author(s):  
Li Feng Fan ◽  
Ying Gao ◽  
Jian Bin Yun ◽  
Lin Feng Dong

Crimping is widely used in production of large diameter submerged-arc welding pipes. Traditionally, the designers obtain the technical parameters for crimping from experience or trial-errors by experiments. To tackle this problem, a theoretical analytical model is proposed to analysis crimping forming process. In this paper, taking the crimping of X80 steel Φ1219mm×22mm×12000mm welding pipe for instance, the theoretical analytical model is constructed by quadratic polynomial curve fitting technique and mechanics theory. And it is verified by a comparison with experiment results. Thus, the presented model of this research provides an effective path to design crimping parameters.


Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 337 ◽  
Author(s):  
Jian Xing ◽  
Yan-yan Cheng ◽  
Zhuo Yi

To improve the effect of multi-point stretch forming of sheet metal, it is proposed in this paper to replace a fixed ball head with a swinging ball head. According to the multi-point dies with different arrangements, this research establishes finite element models of the following stretch forming, i.e., fixed ball heads with conventional arrangement, swinging ball heads with conventional arrangement, swinging ball heads with declining staggered arrangement, and swinging ball heads with parallel staggered arrangement, and then numerical simulation is performed. The simulation results show that by replacing a fixed ball head with a swinging ball head, the surface indentation of the part formed was effectively suppressed, the stress and tension strain distribution of the part formed was improved, and the forming quality was improved; the thickness of the elastic pad was reduced, the springback was reduced and the forming accuracy was improved; and when the ball head was applied to a multi-point die with staggered arrangement, a better forming result was achieved, where the best forming result was achieved in combining the swinging ball heads with the multi-point die with a parallel staggered arrangement. Forming experiments were carried out, and the experimental results were consistent with the trend of numerical simulation results, which verified the correctness of the numerical simulation.


2018 ◽  
Vol 920 ◽  
pp. 70-76 ◽  
Author(s):  
Bao Hang Zhu ◽  
Yi Xi Zhao ◽  
Zhong Qi Yu ◽  
Hui Yan

The T-section aluminum alloy window trim strip sheets are used to improve vehicle appearance. As the mobile scenery line, these window trim strips with claws need high forming accuracy to meet good assembly quality requirement. The top portion of the T-section sheet is stamped to form an edge flange structure. Springback control is essential in forming process. In this paper, the influence of the window trim strip geometric parameters on forming springback is studied. Some finite element models of the process were built with the Dynaform software. The simulation results were verified experimentally. The main conclusions include as belows: The different heights of the stiffeners part in T-section change the stiffness of the part. Although the stiffeners part does not participate in the forming, it also has springback in the forming process. So, it is necessary to study the influence of the flanging part width (W) and the stiffeners part height (H) of the T-section on springback. We set W to 15 mm and change the value of H value according to the real product. The value of springback increases with the increase of H value in the beginning. After ratio of H/W increases to 0.6, the value of springback fluctuates with the increase of H value. When ratio of H/W is about 0.5, the springback values are mostly less than ± 0.5 mm in key sections, which is acceptable.


2015 ◽  
Vol 733 ◽  
pp. 505-508
Author(s):  
Wei Cheng Wu

As an important part of the automobile assembly, automobile frame bears the complex loads from the road and loaded, and be installed car assembly as the carrier, and thus the frame strength and stiffness in the car overall played a very important role in the design. This article use Solid Works to design a frame of a truck, and focus on using the finite element analysis software ANSYS study mechanical analysis and study of the vehicle frame. Here discussed the pure bending conditions and reverse the conditions of static strength, the static stiffness analysis. The analysis showed that the frame of the stress value is less than the ultimate strength of materials to meet the design requirements, but the intensity is too large, so the economy is relatively poor, while considering the local strength of the frame. According to this characteristic of the truck frame, this paper presents a program on the frame lightweight design, the results of optimization makes the weight of frame to reduce, saving raw materials, lowering production costs, improving fuel economy .


Author(s):  
Xiaolan Han ◽  
Zhanfeng Liu

Abstract Titanium alloy is a typical hard-to-machine material, and has a relatively expensive material price. For deep-hole tubes made of titanium alloys, the material utilization rate of direct deep-hole drilling is relatively low, especially for large diameter holes. Deep-hole trepanning provides an effective method that reduces manufacturing cost and improves the material utilization which is used on larger diameter bars. In this paper, deep-hole trepanning tests are carried out on the TC10 titanium alloys to resolve the key technical problems. The thrust force and torque, tool wear, and chip morphology are analyzed based on the different process parameters. The results show that appropriate process parameters can remove the chips easily and reduce the thrust force and tool wear. The titanium alloy deep-hole trepanning has a good drilling effect and solves the problem of drilling deep, large diameter holes in titanium alloy tubes, which has practical significance for reducing production cost and improving material utilization.


Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4081
Author(s):  
Hui Zhang ◽  
Pengcheng Nie ◽  
Zhengyan Xia ◽  
Xuping Feng ◽  
Xiaoxi Liu ◽  
...  

With the increase in demand, artificially planting Chinese medicinal materials (CHMs) has also increased, and the ensuing pesticide residue problems have attracted more and more attention. An optimized quick, easy, cheap, effective, rugged and safe (QuEChERS) method with multi-walled carbon nanotubes as dispersive solid-phase extraction sorbents coupled with surface-enhanced Raman spectroscopy (SERS) was first proposed for the detection of deltamethrin in complex matrix Corydalis yanhusuo. Our results demonstrate that using the optimized QuEChERS method could effectively extract the analyte and reduce background interference from Corydalis. Facile synthesized gold nanoparticles with a large diameter of 75 nm had a strong SERS enhancement for deltamethrin determination. The best prediction model was established with partial least squares regression of the SERS spectra ranges of 545~573 cm−1 and 987~1011 cm−1 with a coefficient of determination (R2) of 0.9306, a detection limit of 0.484 mg/L and a residual predictive deviation of 3.046. In summary, this article provides a new rapid and effective method for the detection of pesticide residues in CHMs.


Author(s):  
Giannoula Chatzopoulou ◽  
Konstantinos Antoniou ◽  
Spyros A. Karamanos

Large-diameter thick-walled steel pipes during their installation in deep-water are subjected to external pressure, which may trigger structural instability due to excessive pipe ovalization with catastrophic effects. The resistance of offshore pipes against this instability mode strongly depends on imperfections and residual stresses introduced by the line pipe manufacturing process. In the present paper, the JCO pipe manufacturing process, a commonly adopted process for producing large-diameter pipes of significant thickness, is examined. The study examines the effect of JCO line pipe manufacturing process on the structural response and resistance of offshore pipes during the installation process using nonlinear finite element simulation tools. At first, the cold bending induced by the JCO process is simulated rigorously, and subsequently, the application of external pressure is modeled until structural instability is detected. For the simulation of the JCO manufacturing process and the structured response of the pipe a two dimensional generalized plane strain model is used. Furthermore, a numerical analysis is also conducted on the effects of line pipe expansion on the structural capacity of the JCO pipe.


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