scholarly journals Effect ofOrientation on Spring back for Component with Hole and without Hole

2021 ◽  
Vol 23 (06) ◽  
pp. 850-856
Author(s):  
Dr. Sharad R. Gawade ◽  
Keyword(s):  
Rolling Direction ◽  
Spring Back ◽  
Elastic Stresses ◽  
Bending Force ◽  
Original Shape ◽  
Different Shapes

Many components are needed to be formed into different shapes depending upon their applications. Whenever the component is formed, it is associated with little or more amount of spring back. It is because of the elastic stresses that remain in the bent-up part. When the bending force is removed, the elastic stresses remaining in the bent up part try to relieve and due to relieving of these elastic stresses the formed up component tries to regain its original shape. This movement of metal due to relieving of stresses is called spring back. In this paper, the effect of orientation on the spring back is studied for components with holes and without holes. The components are formed in U shape along the rolling direction, 450 to the rolling direction, and 900 to the rolling direction, with hole and without a hole in the component. Springback is measured and compared for all the formed-up components. It is seen that the spring back is minimum both for components with holes and without holes formed along the rolling direction. It is also seen that for the components with holes the spring back is reduced as compared with the component without the hole.

scholarly journals Chopstick Robot Driven by X-shaped Soft Actuator

Actuators ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 32
Author(s):  
Kahye Song ◽  
Youngsu Cha
Keyword(s):  
Electrostatic Force ◽  
Input Voltage ◽  
Muscle Control ◽  
Soft Actuator ◽  
Original Shape ◽  
Different Shapes

Chopsticks are a popular tool used every day by 1.5 billion people to pick up pieces of food of different sizes and shapes. Given that the use of chopsticks requires sophisticated muscle control, they are difficult to use for unskilled people. In this study, a chopstick robot that uses a new soft actuator was developed. Firstly, we developed an X-shaped soft actuator and tested its performance. When a voltage was applied to the actuator, the gap in the X shape was reduced by the resulting electrostatic force. Conversely, when the power was turned off, the actuator recovered its original shape owing to the elasticity of its material. We attached the X-shaped soft actuator between the chopsticks. The chopstick robot, controlled by the input voltage, can pick up various objects in the switched-on state and is able to release them when switched off. We tested the performance of the chopstick robot and analyzed the forces acting on the chopsticks. The robot can be used for picking up various objects. Moreover, the X-shaped actuator can be adapted for use in various studies, through different shapes and configurations.

scholarly journals Experimental and Numerical Investigation of AA5052-H32 Al Alloy with U-Profile in Cold Roll Forming

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 470
Author(s):  
Mohanraj Murugesan ◽  
Muhammad Sajjad ◽  
Dong Won Jung
Keyword(s):  
Rolling Direction ◽  
Strip Thickness ◽  
Image Correlation ◽  
Roll Forming ◽  
Al Alloy ◽  
Spring Back ◽  
Cold Roll Forming ◽  
Time Step ◽  
Analytical Technique ◽  
Cold Roll

The cold roll forming process is broadly used to produce a specific shape of cold-roll formed products for their applications in automobiles, aerospace, shipbuilding, and construction sectors. Moreover, a proper selection of strip thickness and forming speed to avoid fracture is most important for manufacturing a quality product. This research aims to investigate the presence of longitudinal bow, the reason behind flange height deviation, spring-back, and identification of thinning location in the cold roll-forming of symmetrical short U-profile sheets. A room temperature tensile test is performed for the commercially available AA5052–H32 Al alloy sheets using Digital Image Correlation (DIC) technique, which allows complete displacement and strain data information at each time-step. The material properties are estimated from the digital images using correlation software for tested samples; the plastic strain ratios are also calculated from samples at 0°, 45°, and 90° to the rolling direction. The tested sample’s surface morphology and the elemental analysis are conducted using scanning electron microscopy (SEM) method and energy-dispersive X-ray spectroscopy (EDS) analytical technique combined with element mapping analysis, respectively. The cold roll forming experiments are systematically carried out, and then finite element analysis is utilized to correlate the experiment with the model. The performed cold roll forming numerical model outcome indicates a good agreement with the experimental measurements. Overall, the presented longitudinal strain was observed to influence the geometry profile. The spring-back is also noticed at the profile tail end and is more pronounced at high forming speed with lower strip thickness. Conversely, while the forming speed is varied, the strain and stress variations are observed to be insignificant, and the similar results also are recognized for the thinning behavior.

scholarly journals Effect of a Compound Energy Field with Temperature and Ultrasonic Vibration on the Material Properties and Bending Process of TC2 Titanium Alloy

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7192
Author(s):  
Tiejun Gao ◽  
Kaifeng Wang ◽  
Zhiyuan Ling ◽  
Zhongjin Wang
Keyword(s):  
Titanium Alloy ◽  
Elastic Modulus ◽  
Yield Strength ◽  
Ultrasonic Vibration ◽  
Strain Curve ◽  
Spring Back ◽  
Forming Process ◽  
Energy Field ◽  
Bending Force ◽  
Single Temperature

Due to the low formability and forming quality of titanium alloy, the forming process of a compound energy field (CEF) with temperature and ultrasonic vibration was proposed. Tensile tests were carried out to investigate the effect of the CEF on the true stress–strain curve, yield strength, elastic modulus, and other mechanical properties of the TC2 titanium alloy. Bending tests assisted by CEF were also performed to investigate the effect of different parameters of the CEF on bending force, spring-back, bending fillet radius, and microstructure of TC2 titanium. The results demonstrate that compared to the process under a single-temperature field, the CEF can reduce yield strength, elastic modulus, bending force, bending fillet, and the spring-back angle, which shows that the CEF can further increase the high-temperature softening effect of TC2 titanium. Furthermore, this effect becomes more remarkable when ultrasonic vibration energy increases. As a result, the formability of titanium alloy can be improved.

Stresses in high-pressure taper-hub flanges with recesses for nut facings

1975 ◽  
Vol 10 (2) ◽  
pp. 119-128 ◽  
Author(s):  
H Fessler ◽  
D A Perry
Keyword(s):  
High Pressure ◽  
Stress Concentrations ◽  
British Standard ◽  
Elastic Stresses ◽  
Different Shapes ◽  
Set Up

Frozen-stress photoelastic analyses were carried out to determine the elastic stresses, due to initial bolting only, set up in a British Standard 250 mm taper-hub flange rated at 250 bar and in 15 different shapes of flange in which recesses were used to reduce the diameter and the peak stresses. It was found that stress concentrations occur at the recess fillets as wel as at the flange fillet. Two shapes were determined which are smaller and lighter and have lower peak stresses than the B.S. shape without recesses.

Morphology Change of Extrusion Molded Crystalline Polymer by Rolling Process

2011 ◽  
Vol 391-392 ◽  
pp. 595-599 ◽  
Author(s):  
Takuya Murata ◽  
Jian Hui Qiu ◽  
Eiichi Sakai ◽  
Xue Li Wu ◽  
Makoto Kudo
Keyword(s):  
Internal Structure ◽  
Cross Section ◽  
Molecular Orientation ◽  
Rolling Direction ◽  
Crystalline Polymer ◽  
Dimensional Change ◽  
Rolling Process ◽  
Spring Back ◽  
Structure And Morphology ◽  
High Reduction

In this work, the spring back, dimensional change, internal structure and morphology of extruded polypropylene were investigated in order to consider the rolling characteristic. It was found that the internal structure, molecular orientation and crystallinity were changed a little by high spring back under low reduction in thickness. Crystal structure was extended along the rolling direction with high reduction in thickness due to the increase of plastic deformation. As a result, molecular orientation increased and crystallinity decreased at over 30% of reduction in thickness. Crystalline structure of surface was similar to the center part in cross-section at 70% reduction in thickness, and molecular orientation was constant.

Elastic stresses due to torque transmitted through the prismatic part of keyed connections part II: Effect of shape with usual fits and friction

1982 ◽  
Vol 17 (4) ◽  
pp. 215-222 ◽  
Author(s):  
H Fessler ◽  
M Eissa
Keyword(s):  
Large Range ◽  
Elastic Stresses ◽  
Contact Points ◽  
Different Shapes ◽  
Better Than

Models of 25 different shapes of keyed connections have been loaded by a large range of torques, using ordinary and frozen-stress photoelasticity. Empirical formulae have been derived for five contact points where the stresses are concentrated. These formulae give good predictions over the complete shape range of the metric and inch standards. The latter is consistently better than the former.

Structural phenomena in the growth of carbon nanotubes

1993 ◽  
Vol 51 ◽  
pp. 750-751
Author(s):  
Jun Jiao
Keyword(s):  
Carbon Nanotubes ◽  
Growth Mechanism ◽  
Carbonaceous Material ◽  
Cluster Growth ◽  
Structural Elements ◽  
Rich Variety ◽  
Different Shapes ◽  
Point To Point

HREM studies of the carbonaceous material deposited on the cathode of a Huffman-Krätschmer arc reactor have shown a rich variety of multiple-walled nano-clusters of different shapes and forms. The preparation of the samples, as well as the variety of cluster shapes, including triangular, rhombohedral and pentagonal projections, are described elsewhere.The close registry imposed on the nanotubes, focuses attention on the cluster growth mechanism. The strict parallelism in the graphitic separation of the tube walls is maintained through changes of form and size, often leading to 180° turns, and accommodating neighboring clusters and defects. Iijima et. al. have proposed a growth scheme in terms of pentagonal and heptagonal defects and their combinations in a hexagonal graphitic matrix, the first bending the surface inward, and the second outward. We report here HREM observations that support Iijima’s suggestions, and add some new features that refine the interpretation of the growth mechanism. The structural elements of our observations are briefly summarized in the following four micrographs, taken in a Hitachi H-8100 TEM operating at an accelerating voltage of 200 kV and with a point-to-point resolution of 0.20 nm.

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