Closed Die Forging of Axisymmetric Shapes from Cylindrical Billets of Strain Hardening and Strain Rate Sensitive Material: Experimental Results and Theoretical Predictions

1980 ◽  
pp. 61-66
Author(s):  
M. S. J. Hashmi ◽  
F. B. Klemz
Keyword(s):  
Strain Rate ◽  
Strain Hardening ◽  
Experimental Results ◽  
Sensitive Material ◽  
Die Forging ◽  
Closed Die Forging ◽  
Theoretical Predictions

Closed-Die Forging of Gear-Like Elements

1998 ◽  
Vol 120 (1) ◽  
pp. 34-41 ◽  
Author(s):  
A. El-Domiaty ◽  
M. Shabara ◽  
M. Al-Ansary
Keyword(s):  
Upper Bound ◽  
Pure Aluminum ◽  
Experimental Results ◽  
Frictional Stress ◽  
Die Geometry ◽  
Die Forging ◽  
Closed Die Forging ◽  
Theoretical Predictions ◽  
Upper Bound Technique ◽  
Forging Die

Closed die forging of spur gears is investigated using the slab method and the upper bound technique. The tooth regions are approximated by prismatic rectangular sections. The velocity field comprising three unit deformation regions is used. A constant frictional stress between workpiece and forging die is assumed. The average punch pressure normalized by the flow stress of the gear material is determined theoretically and compared with experimental results. The experimental work is carried out on a commercial pure aluminum (Al 1100) at room temperature. The forging process is carried out using one die geometry without using any additional blocker (preform) dies. The theoretical predictions of forging pressures using slab and upper bound methods agree fairly well with the experimental results.

Tensile Behavior of Ti-5Al-2.5Sn Alloy at Low Temperatures and High Strain Rates

2019 ◽  
Vol 794 ◽  
pp. 135-141
Author(s):  
Bin Zhang ◽  
Yang Wang
Keyword(s):  
Strain Rate ◽  
Strain Hardening ◽  
Low Temperatures ◽  
High Strain ◽  
Testing Temperature ◽  
Tensile Behavior ◽  
Experimental Results ◽  
Strain Rates ◽  
Increasing Temperature ◽  
Strain Hardening Rate

The mechanical responses of Ti-5Al-2.5Sn alloy at low temperatures were investigated under quasi-static and dynamic tensile loads using MTS system and SHTB system, respectively. Tensile stress-strain curves were obtained over the temperature range of 153 to 298K and the rate range of 0.001 to 1050 s-1. Experimental results indicate that the tensile behavior of Ti-5Al-2.5Sn alloy is dependent on strain rate and temperature. Yield stress and flow stress increase with increasing strain rate and decrease with increasing temperature. Results also indicate that strain hardening rate of Ti-5Al-2.5Sn alloy is lower at high strain rate, while strain hardening rate varies little with testing temperature. The Khan-Huang-Liang constitutive model was chosen to characterize the tensile responses of Ti-5Al-2.5Sn alloy at low temperatures and different strain rates. The model results coincide well with the experimental results within the tested temperature and rate ranges.

Modeling High Strain Rate Viscoplastic Deformations Combined with Phase Changes

2011 ◽  
Vol 172-174 ◽  
pp. 778-783
Author(s):  
Frank Montheillet ◽  
Gilles Roy
Keyword(s):  
Strain Rate ◽  
Strain Hardening ◽  
High Strain ◽  
Phase Changes ◽  
Temperature Sensitive ◽  
Sensitive Material ◽  
Two Phase ◽  
Expansion Test ◽  
Self Heating ◽  
Complex Interactions

Metallic materials submitted to high strain rates upon dynamic loading can undergo phase changes induced by strains, stresses, and/or temperature increase associated with self-heating. Various mechanical and metallurgical assumptions have been proposed and implemented in numerical codes to deal with such complex interactions. In order to assess their respective influences, a simple nearly analytical model was developed and applied to the classical sphere expansion test carried out on a two-phase strain hardening, strain rate and temperature sensitive material. In this paper, classical homogenization assumptions are compared for deriving the overall material flow stress. Strain hardening transfer upon phase transformation is accounted for. Finally, the respective weights of the various contributions to the work rate, associated with stored energy, self-heating, and phase change, are analyzed.

Plastic Buckling of Torispherical and Ellipsoidal Shells Subjected to Internal Pressure

1981 ◽  
Vol 195 (1) ◽  
pp. 329-345 ◽  
Author(s):  
G D Galletly
Keyword(s):  
Stainless Steel ◽  
Internal Pressure ◽  
Strain Hardening ◽  
Design Procedure ◽  
Experimental Results ◽  
Elastic Plastic ◽  
Theoretical Predictions ◽  
The Usa ◽  
Simplifying Assumptions ◽  
The Uk

Thin metallic torispherical shells are used frequently in many industries as end closures on cylinders subjected to internal pressure and, for those torispheres which have diameter/thickness ratios greater than 400, elastic-plastic internal pressure buckling may occur. As yet, however, code rules to assist the designer with this buckling problem are not available in either the UK or the USA and one of the aims of this paper is to help to correct this situation. Elastic-plastic internal buckling pressures, for a range of perfect torispherical geometries and obtained with the aid of a sophisticated computer program, are given in the first part of the paper. These pcr's are then utilized (a) to develop a relatively simple equation for predicting the internal buckling pressures of torispherical shells and (b) to assess the accuracy of another, even simpler, approximate buckling equation which was suggested recently (1). Next, the correlation between the theoretical predictions of pcr and the experimental results is considered. The tests taken into account were (a) 5 in diameter machined model torispherical shells, (b) 20 in diameter spun ellipsoidal shells, and (c) 54 in diameter pressed and spun torispherical shells. The shells in (b) and (c) were not stress-relieved and a number of them were made from strain-hardening materials. The agreement between theory and experiment was good for the machined models and fairly satisfactory for the spun models. For the ellipsoidal shells there was also reasonably good agreement between the predictions of two simple design equations and the experimental results. The problems associated with the prediction of the internal buckling pressures of spun torispherical shells made from strain-hardening materials (e.g. stainless steel) are considered in the last section of the paper. Taking the results of the previous sections of the paper into account, and making some simplifying assumptions, a tentative design procedure for predicting the pcr's of these ‘as-manufactured’ spun torispherical shells is proposed. This procedure is then checked by comparing its predictions with experimental buckling pressures found for eleven spun stainless steel heads and six crown and segment ones. The agreement between experiment and theory was quite satisfactory and it is hoped that the suggested procedure might become the first step towards the development of experimentally validated code rules for preventing the occurrence of buckling in these dished ends.

Upper Bound Analysis of Axisymmetric, Closed-Die Forgings

1981 ◽  
Vol 103 (1) ◽  
pp. 109-112 ◽  
Author(s):  
P. Dadras
Keyword(s):  
Velocity Field ◽  
Upper Bound ◽  
Deformation Zone ◽  
Admissible Velocity ◽  
Upper Bound Analysis ◽  
Die Forging ◽  
Closed Die Forging ◽  
Theoretical Predictions ◽  
Experimental Values ◽  
Bound Analysis

A kinematically admissible velocity field for axisymmetric closed die forging is proposed. The forging power and load are calculated and compared with experimental values. It is found that the theoretical predictions give estimates that are substantially higher than actual loads and powers. Also, the effect of different parameters on the height and shape of the deformation zone is investigated and it is shown that the height is independent of flash thickness and length. The angle of convergence of flow from the die to the flash decreases as the flash thickness is increased.

The Effect of Strain Rate on the Material Characteristics of Nickel-Based Superalloy Inconel 718

2007 ◽  
Vol 340-341 ◽  
pp. 283-288 ◽  
Author(s):  
Jung Han Song ◽  
Hoon Huh
Keyword(s):  
Dynamic Response ◽  
High Strain Rate ◽  
Strain Rate ◽  
Turbine Blade ◽  
Inconel 718 ◽  
High Speed ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Experimental Results ◽  
Stress Wave Propagation

The dynamic response of the turbine blade materials is indispensable for analysis of erosions of turbine blades as a result of impulsive loading associated with gas flow. This paper is concerned with the dynamic material properties of the Inconel 718 alloy which is widely used in the high speed turbine blade. The dynamic response at the corresponding level of the strain rate should be acquired with an adequate experimental technique and apparatus due to the inertia effect and the stress wave propagation. In this paper, the dynamic response of the Inconel 718 at the intermediate strain rate ranged from 1/s to 400/s is obtained from the high speed tensile test and that at the high strain rate above 1000/s is obtained from the split Hopkinson pressure bar test. The effects of the strain rate on the dynamic flow stress, the strain rate sensitivity and the failure elongation are evaluated with the experimental results. Experimental results from both the quasi-static and the high strain rate up to 3000/s are interpolated in order to construct the constitutive relation that should be applied to simulate the dynamic behavior of the turbine blade made of the Inconel 718.

scholarly journals Quantitative Experimental and Theoretical Investigations on the Interaction of Shock Waves with Magnetic Fields

1969 ◽  
Vol 24 (10) ◽  
pp. 1449-1457
Author(s):  
H. Klingenberg ◽  
F. Sardei ◽  
W. Zimmermann
Keyword(s):  
Magnetic Fields ◽  
Shock Waves ◽  
Physical Model ◽  
Spectroscopic Method ◽  
Experimental Results ◽  
Dimensional Theory ◽  
One Dimensional ◽  
Theoretical Investigations ◽  
Theoretical Predictions ◽  
Interaction Of Shock Waves

Abstract In continuation of the work on interaction between shock waves and magnetic fields 1,2 the experiments reported here measured the atomic and electron densities in the interaction region by means of an interferometric and a spectroscopic method. The transient atomic density was also calculated using a one-dimensional theory based on the work of Johnson3 , but modified to give an improved physical model. The experimental results were compared with the theoretical predictions.

scholarly journals Experimental study of the $ \gamma p \rightarrow K^{0}\Sigma^{+}$, $ \gamma n \rightarrow K^{0} \Lambda$, and $ \gamma n \rightarrow K^{0} \Sigma^{0}$ reactions at the Mainz Microtron

2019 ◽  
Vol 55 (11) ◽  
Author(s):  
C. S. Akondi ◽  
K. Bantawa ◽  
D. M. Manley ◽  
S. Abt ◽  
P. Achenbach ◽  
...  
Keyword(s):  
Experimental Study ◽  
Cross Sections ◽  
Differential Cross ◽  
Legendre Polynomials ◽  
Neutral Kaon ◽  
Experimental Results ◽  
Differential Cross Sections ◽  
Theoretical Predictions ◽  
Photoproduction Reactions ◽  
Insight Into

Abstract.This work measured $ \mathrm{d}\sigma/\mathrm{d}\Omega$dσ/dΩ for neutral kaon photoproduction reactions from threshold up to a c.m. energy of 1855MeV, focussing specifically on the $ \gamma p\rightarrow K^0\Sigma^+$γp→K0Σ+, $ \gamma n\rightarrow K^0\Lambda$γn→K0Λ, and $ \gamma n\rightarrow K^0 \Sigma^0$γn→K0Σ0 reactions. Our results for $ \gamma n\rightarrow K^0 \Sigma^0$γn→K0Σ0 are the first-ever measurements for that reaction. These data will provide insight into the properties of $ N^{\ast}$N* resonances and, in particular, will lead to an improved knowledge about those states that couple only weakly to the $ \pi N$πN channel. Integrated cross sections were extracted by fitting the differential cross sections for each reaction as a series of Legendre polynomials and our results are compared with prior experimental results and theoretical predictions.

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