Experimental and Theoretical Investigation of the Plastic Deformation of Cantilever Beams Subjected to Impulsive Loading

1962 ◽  
Vol 29 (4) ◽  
pp. 719-728 ◽  
Author(s):  
S. R. Bodner ◽  
P. S. Symonds
Keyword(s):  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Strain Rate ◽  
Yield Stress ◽  
Impulsive Loading ◽  
Cantilever Beams ◽  
Rigid Plastic ◽  
Impulsive Load ◽  
Velocity Change ◽  
Plastic Theory

The experimental techniques and the results obtained in a program to evaluate the assumptions of dynamic, rigid-plastic theory of beams are presented. The experiments used steel and aluminum-alloy cantilever beams subjected to either a rapid velocity change at the base or to an impulsive load at the tip. A rigid-plastic theory that includes the strain-rate dependence of the yield stress and geometry changes is outlined for the case of the tip impulsive loading. The predictions of this theory are in satisfactory agreement with the experimental results.

Comparative Study of the Dynamic Behavior of AA2519 Aluminum Alloy in T6 and T8 Temper Conditions

2019 ◽  
Author(s):  
Adewale Olasumboye ◽  
Gbadebo Owolabi ◽  
Olufemi Koya ◽  
Horace Whitworth ◽  
Nadir Yilmaz
Keyword(s):  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Stress Response ◽  
Flow Stress ◽  
Yield Strength ◽  
Strain Rate ◽  
High Strain ◽  
Second Phase ◽  
Strain Rates ◽  
High Strain Rates

Abstract This study investigates the dynamic response of AA2519 aluminum alloy in T6 temper condition during plastic deformation at high strain rates. The aim was to determine how the T6 temper condition affects the flow stress response, strength properties and microstructural morphologies of the alloy when impacted under compression at high strain rates. The specimens (with aspect ratio, L/D = 0.8) of the as-cast alloy used were received in the T8 temper condition and further heat-treated to the T6 temper condition based on the standard ASTM temper designation procedures. Split-Hopkinson pressure bar experiment was used to generate true stress-strain data for the alloy in the range of 1000–3500 /s strain rates while high-speed cameras were used to monitor the test compliance with strain-rate constancy measures. The microstructures of the as received and deformed specimens were assessed and compared for possible disparities in their initial microstructures and post-deformation changes, respectively, using optical microscopy. Results showed no clear evidence of strain-rate dependency in the dynamic yield strength behavior of T6-temper designated alloy while exhibiting a negative trend in its flow stress response. On the contrary, AA2519-T8 showed marginal but positive response in both yield strength and flow behavior for the range of strain rates tested. Post-deformation photomicrographs show clear disparities in the alloys’ initial microstructures in terms of the second-phase particle size differences, population density and, distribution; and in the morphological changes which occurred in the microstructures of the different materials during large plastic deformation. AA2519-T6 showed a higher susceptibility to adiabatic shear localization than AA2519-T8, with deformed and bifurcating transformed band occurring at 3000 /s followed by failure at 3500 /s.

Molecular dynamics simulations of the effect of temperature and strain rate on the plastic deformation of body centred cubic iron nanowires

2021 ◽  
pp. 1-19
Author(s):  
Qian Wu ◽  
Yong Wang ◽  
Tao Han ◽  
Hongtao Wang ◽  
Laihui Han ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Plastic Deformation ◽  
Strain Rate ◽  
Yield Stress ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Strain Curve ◽  
Dislocation Slip ◽  
Stress Strain Curve ◽  
Stress Strain

Abstract The tensile tests of BCC Fe nanowires were simulated through molecular dynamics methods. The temperature and strain rate effects on the mechanical properties as well as the orientation-dependent plastic deformation mechanism were analyzed. For [001]-oriented BCC Fe nanowires, as the temperature increased, the yield stress and Young's modulus decreased. While the yield stress and Young's modulus increased as the strain rate increased. With the increase of temperature, when the temperature was less than 400 K, the twin propagation stress decreased dramatically, and then tended to reach a saturation value at higher temperatures. Under different temperatures and strain rates, the [001]-oriented Fe nanowires all deformed by twinning. The oscillation stage in the stress-strain curve corresponds to the process from the nucleation of the twin to the reorientation of the nanowire. For [110]-oriented Fe nanowires, the plastic deformation is dominated by dislocation slip. The independent events such as the nucleation, slip, and annihilation of dislocations are the causes of the unsteady fluctuations in the stress-strain curve. The Fe nanowires eventually undergo shear damage along the dominant slip surface.

Rigid-Plastic Beams Under Uniformly Distributed Impulses

1965 ◽  
Vol 32 (3) ◽  
pp. 481-488 ◽  
Author(s):  
A. L. Florence ◽  
R. D. Firth
Keyword(s):  
Plastic Deformation ◽  
Strain Hardening ◽  
Large Deflections ◽  
Rigid Plastic ◽  
Clamped Beams ◽  
Plastic Theory

This paper contains the description and results of experiments in which pinned and clamped beams are subjected to uniformly distributed impulses large enough to cause considerable plastic deformation. The final permanent shapes are compared with those predicted by the rigid-plastic theory. They are also compared with the shapes predicted when the theory takes some account of large deflections and strain-hardening.

Plastic Deformation of Impulsively Loaded Straight Clamped Beams

1965 ◽  
Vol 32 (1) ◽  
pp. 7-10 ◽  
Author(s):  
John S. Humphreys
Keyword(s):  
Plastic Deformation ◽  
Beam Theory ◽  
Upper Bounds ◽  
Impulsive Loading ◽  
Steel Beams ◽  
Rigid Plastic ◽  
First Approximation ◽  
Ballistic Pendulum ◽  
Clamped Beams ◽  
Flat Steel

A series of tests was conducted on flat steel beams of various sizes and material properties, using sheet explosive to provide sufficiently high uniform impulsive loading to produce significant plastic deformation. The beams were attached to a ballistic pendulum for measurement of applied impulse, and were photographed with a Fastax camera during deformation. The resulting final deformations are compared with the rigid-plastic theory of Symonds and Mentel, which is seen to give upper bounds that are in general higher by about 20–30 percent than the deformations observed. A fairly good first approximation to maximum deflection for engineering purposes is in fact obtained simply by using rigid-plastic beam theory (including axial constraints).

The Plastic Deformation of a Cantilever Beam With Strain-Rate Sensitivity Under Impulsive Loading

1964 ◽  
Vol 31 (1) ◽  
pp. 38-42 ◽  
Author(s):  
Thomas C. T. Ting
Keyword(s):  
Plastic Deformation ◽  
Strain Rate ◽  
Cantilever Beam ◽  
Strain Rate Sensitivity ◽  
Numerical Solutions ◽  
Power Series Expansion ◽  
Rate Sensitivity ◽  
Plastic Behavior ◽  
Rigid Plastic ◽  
Tip Mass

This paper presents an analysis of the plastic deformation of a cantilever beam with an attached tip mass, based on the assumption of rigid-plastic behavior with strain-rate sensitivity, under an impulsive load at the tip. Numerical solutions of the equations of motion which appear as two nonlinear simultaneous integral equations are presented. The possibility of power-series expansion is also indicated. Finally, approximate solutions are given, and the results are compared with the more exact solutions and with experimental data.

scholarly journals Microstructure and Mechanical Properties of Laser Welded 6061-T6 Aluminum Alloy under High Strain Rates

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1145
Author(s):  
Jincheng Nie ◽  
Shengci Li ◽  
Huilong Zhong ◽  
Changjing Hu ◽  
Xiangsong Lin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Aluminum Alloy ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Base Material ◽  
Strain Rates ◽  
High Strain Rates ◽  
Plastic Deformation Region

Laser welding is widely used for the joining of aluminum alloy in the automotive industry, and the vehicles produced are inevitably subjected to high strain rate loading during their service. Therefore, this paper studied the mechanical properties of 6061-T6 aluminum alloy and its laser welded joint at strain rates between 0.0003 and 1000 s−1. Results showed that the microstructure of welded material (WM) was much finer than base material (BM), typical columnar crystals grew perpendicularly to the fusion line, and the minimum hardness value (~56 HV) was obtained inside WM. The strength and dynamic factors of BM and WM increased with increasing strain rate, and the strength of WM was less sensitive to strain rate compared with BM. The strain rate effect was not homogenous in the plastic deformation region. The modified Johnson–Cook (J–C) model which introduced the term C = C1 + C2·ε could well describe the dynamic plastic deformation of BM. However, the fitted results of the simplified J–C model were overall better than the modified J–C model for WM, especially for high strain rate (1000 s−1). These findings will benefit the determination of the dynamic deformation behavior of laser welded aluminum alloy under high strain rates, and could provide a better understanding of lightweight and the safety of vehicles.

Study of Forging Forming of 7075 Aluminum Alloy Bicycle Pedal

2012 ◽  
Vol 579 ◽  
pp. 101-108 ◽  
Author(s):  
Dyi Cheng Chen ◽  
Fung Ling Nian ◽  
Jiun Ru Shiu ◽  
Wen Hsuan Ku
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Aluminum Alloy ◽  
Effective Strain ◽  
High Strength ◽  
Mold Temperature ◽  
Grain Structure ◽  
7075 Aluminum Alloy ◽  
Rigid Plastic ◽  
Plastic Deformation Behavior

Forging is simple and inexpensive in mass production. Metallic materials are processed through plastic deformation. This not only changes the appearance but also changes the internal organization of materials that improve mechanical properties. However, regarding manufacturing of plastic products, many processing factors must be controlled to obtain the required plastic strain and desired tolerance values. In this paper, we employed rigid-plastic finite element (FE) DEFORMTM software to investigate the plastic deformation behavior of an aluminum alloy (A7075) workpiece as it used to forge bicycle pedals. First we use Solid works 2010 3D graphics software to design the bicycle pedal of the mold and appearance, moreover import finite element (FE) DEFORMTM 3D software for analysis. The paper used rigid-plastic model analytical methods, and assuming mode to be rigid body. A series of simulation analyses in which the variables depend on different temperatures of the forging billet, round radius size of ram, punch speed, and mold temperature were revealed to confirm the predicted aluminum grain structure, effective stress, effective strain, and die radial load distribution for forging a bicycle pedal. The analysis results can provide references for forming bicycle pedal molds. Finally, this study identified the finite element results for high-strength design suitability of a 7075 aluminum alloy bicycle pedal.

A Study on Dynamic Plastic Deformation Behavior of 5052 Aluminum Alloy

2019 ◽  
Vol 812 ◽  
pp. 45-52
Author(s):  
Ping Song ◽  
Wen Bin Li ◽  
Xiao Ming Wang
Keyword(s):  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Split Hopkinson Pressure Bar ◽  
Rate Sensitivity ◽  
Plastic Behavior ◽  
Hopkinson Pressure Bar ◽  
Plastic Deformation Behavior ◽  
Constitutive Parameters

In this paper, the effects of temperature and strain rate on the plastic deformation behavior of 5052 aluminum alloy were investigated by quasi-static tensile test and split Hopkinson pressure bar (SHPB) experiments. Meanwhile, the stress-strain relations obtained through these experiments were employed for calibrating Johnson-Cook (J-C) plastic flow constitutive parameters of 5052 aluminum alloy. The results show that the strain rate sensitivity of 5052 aluminum alloy is insignificant in the range of 0.001s-1~3000s-1, while temperature has a great effect on the material plastic behavior. The experimental data are basically consistent with the predicted outcome of J-C constitutive model.

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