scholarly journals Research on Hydraulic Push-Pull Bending Process of Ultra-Thin-Walled Tubes

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1932
Author(s):  
Xin Zhang ◽  
Changcai Zhao ◽  
Bing Du ◽  
Duan Chen ◽  
Yang Li ◽  
...  
Keyword(s):  
Internal Pressure ◽  
High Performance ◽  
High Strength ◽  
Combined Loading ◽  
Optimum Process ◽  
Hydraulic Pressure ◽  
Fe Model ◽  
Bending Process ◽  
Thin Walled Tube ◽  
Thin Walled

Due to their high strength, high performance, and lightweight characteristics, bent tubes are widely used in many high-end industries, such as aviation, aerospace, shipbuilding, automobile, and petrochemical industries. Ultra-thin-walled (thickness-to-diameter ratio t/D < 0.01) bent tubes are more prone to wrinkling, fracture, and cross-section distortion than ordinary bent tubes, which are difficult to form integrally by traditional bending processes. In this paper, a new bending process with combined loading of hydraulic pressure, push, and pull was proposed to provide a new method for the bending of ultra-thin-walled tube. This process is characterized by the ability to optimize the combination of push, pull, and internal pressure according to the actual bending process in order to minimize the wrinkling of ultra-thin-walled tube during bending. Based on ABAQUS finite element (FE) software, the FE model of the hydraulic push-pull bending process for ultra-thin-walled tube was established. The influence of internal pressure, die clearance, and friction coefficient on the forming quality of bent tubes was discussed, and the optimum process parameters were obtained. Bent tubes with an initial thickness of 0.3 mm, diameter of 60 mm, and bending radius of 165 mm were manufactured in experiments. Through the comparative analysis of experiment and simulation, the accuracy of the FE simulation was verified.

scholarly journals Optimal Design of the Shape of a Non-Ball Mandrel for Thin-Walled Tube Small Radius Cold Bending

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1221
Author(s):  
Lu Bai ◽  
Jun Liu ◽  
Ziang Wang ◽  
Shuanggui Zou
Keyword(s):  
Ideal Point ◽  
Small Radius ◽  
Grey Wolf Optimizer ◽  
Forming Quality ◽  
Hollow Section ◽  
Cold Bending ◽  
Bending Process ◽  
Before And After ◽  
Thin Walled Tube ◽  
Thin Walled

In the field of cold bending, it is necessary to use ball mandrels, especially to bend thin-walled tubes with a small radius. However, the bending process with a ball mandrel is complex and expensive, and it is easy to jam the core ball inside the tube. To solve these issues, we designed two kinds of hollow non-ball mandrel schemes with low stiffness that were suitable for the small radius bending of thin-walled tubes. We evaluated the forming quality of cold bending numerically and the influence of the hollow section length and thickness on the forming indices. Our results showed that the thickness of the hollow section has a greater influence on forming quality than the length. As the hollow section’s thickness increased, the wrinkling rate first declined by approximately 40% and then increased by above 50%. When the thickness was 11 mm in scheme 1 and 13 mm in scheme 2, the wrinkling rate reached minimum values of 1.32% and 1.50%, respectively. As the hollow section’s thickness increased, the flattening rate decreased by more than 60% and the thinning rate increased by about 40%. A multi-objective optimization of forming indices was carried out by ideal point method and grey wolf optimizer. By comparing the forming results before and after optimization, the feasibility of using the proposed hollow mandrel was proved, and the hollow mandrel scheme of standard cylinder is therefore recommended.

Investigation on the influence of mandrel on the forming quality of thin-walled tube during free bending process

2021 ◽  
Vol 72 ◽  
pp. 215-226
Author(s):  
Cheng Cheng ◽  
Hao Chen ◽  
Jiaxin Guo ◽  
Xunzhong Guo ◽  
Yuanji Shi
Keyword(s):  
Forming Quality ◽  
Bending Process ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Free Bending

Tube-Bulging Under Internal Pressure and Axial Force

1973 ◽  
Vol 95 (4) ◽  
pp. 219-223 ◽  
Author(s):  
D. M. Woo
Keyword(s):  
Internal Pressure ◽  
Numerical Solution ◽  
Axial Force ◽  
Compressive Load ◽  
Experimental Results ◽  
Longitudinal Stress ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Tube Bulging

A numerical solution for analysis of the bulging process of a thin-walled tube under internal pressure and axial force is proposed. The solution is applied to a case in which the longitudinal stress resulted from internal pressure and external compressive load is tensile along the whole length of the bulged tube. To verify whether the solution is applicable, theoretical and experimental results on the bulging of copper tubes have been obtained and are compared in this paper.

scholarly journals Mechanical Properties of High-Strength High-Performance Reinforced Concrete Shaft Lining Structures in Deep Freezing Wells

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Shilong Peng ◽  
Chuanxin Rong ◽  
Hua Cheng ◽  
Xiaojian Wang ◽  
Mingjing Li ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
Shear Failure ◽  
High Performance Concrete ◽  
High Strength ◽  
Strength Criterion ◽  
Hydraulic Pressure ◽  
Element Analysis ◽  
Deep Freezing ◽  
Shaft Lining

As coal resources must be mined from ever deeper seams, high-strength, high-performance concrete shaft linings are required to resist the load of the soil surrounding the deep freezing well. In order to determine the optimal concrete mix for the unique conditions experienced by such high-strength high-performance reinforced concrete shaft lining (HSHPRCSL) structures in deep freezing wells, an experimental evaluation of scaled HSHPRCSL models was conducted using hydraulic pressure load tests. It was observed that as the specimens ruptured, plastic bending of the circumferential reinforcement occurred along the failure surface, generated by compression-shear failure. These tests determined that HSHPRCSL capacity was most affected by the ultimate concrete uniaxial compressive strength and the thickness-diameter ratio and least affected by the reinforcement ratio. The experimental results were then used to derive fitting equations, which were compared with the results of theoretical expressions derived using the three-parameter strength criterion for the ultimate bearing capacity, stress, radius, and load in the elastic and plastic zones. The proposed theoretical equations yielded results within 8% of the experimentally fitted results. Finally, the finite element analysis method is used to verify the abovementioned results, and all errors are less than 12%, demonstrating reliability for use as a theoretical design basis for deep HSHPRCSL structures.

Genetic Algorithm-Based Optimization of the Thin-Walled Tube of High Strength Aluminum Alloy in Diamond Turning Process

2011 ◽  
Vol 175 ◽  
pp. 347-351
Author(s):  
Bao Xing Zhang ◽  
Bin Lin ◽  
Zhi Lin Han ◽  
Lei Zhang
Keyword(s):  
Genetic Algorithm ◽  
Aluminum Alloy ◽  
Optimization Technique ◽  
High Strength ◽  
Cutting Parameters ◽  
Diamond Turning ◽  
Turning Process ◽  
High Strength Aluminum Alloy ◽  
Thin Walled Tube ◽  
Thin Walled

Optimization of the cutting parameters is one of the most important contents in diamond turning process of the thin-walled tube of high strength aluminum alloy. Cutting conditions have an influence on reducing the production time and deciding the quality of the final workpiece. This paper proposes an optimization technique based on genetic algorithms (GA) for the determination of the cutting parameters. As the experimental results show, it is very efficient that the proposed genetic algorithm-based procedure for solving this problem.

Study on Factors of Axial Crushing of Thin-Walled High-Strength Steel Sections Used in Passenger Car

2014 ◽  
Vol 989-994 ◽  
pp. 898-902
Author(s):  
Gui Fan Zhao ◽  
Yao Wei Hu ◽  
Xiao Cheng ◽  
Ke Xiao
Keyword(s):  
Finite Element ◽  
High Strength Steel ◽  
Spot Welding ◽  
High Strength ◽  
Element Model ◽  
Welding Seam ◽  
Seam Welding ◽  
Thin Walled Tube ◽  
Steel Sections ◽  
Thin Walled

This paper firstly studied the structure of front longitudinal, then reviewing comprehensive literature draw the similarity of collision of the thin-walled tube and front longitudinal,finally ensure the study of collision of the thin-walled tube. And establishing three kinds of thin-walled welded rectangular beam finite element model of spot welding, seam welding and laser welding, arrive a more superior technology through researching and analyzing the model.

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