scholarly journals The Effect of Test System Misalignment in the Dynamic Tension Test

1982 ◽  
Vol 104 (4) ◽  
pp. 285-290
Author(s):  
Han C. Wu ◽  
T. P. Wang ◽  
M. C. Yip
Keyword(s):  
Plastic Strain ◽  
Strain Rate ◽  
Constant Strain Rate ◽  
Test System ◽  
Tension Test ◽  
Neutral Axis ◽  
Dynamic Tension ◽  
Test Sheet

An analysis of test system misalignment is presented for dynamic tension test. Sheet type rectangular 1100-0 aluminum specimens are used for discussion. For a constant strain rate tension test, the strain rate is constant only on the neutral axis of the specimen. The lower the strain rate is, the more significant the misalignment errors become. The neutral axis will shift away from the centerline of the specimen as the plastic strain increases. But, it will reach a limit and will not completely move back to the centerline.

An Experimental Study on the Effect of Prior Plastic Straining on Creep Behavior of 304 Stainless Steel

1993 ◽  
Vol 115 (2) ◽  
pp. 200-203 ◽  
Author(s):  
Z. Xia ◽  
F. Ellyin
Keyword(s):  
Stainless Steel ◽  
Plastic Strain ◽  
Strain Rate ◽  
Creep Behavior ◽  
Test Procedure ◽  
Constant Strain Rate ◽  
304 Stainless Steel ◽  
Creep Model ◽  
Plastic Strain Rate ◽  
Creep Tests

Constant strain-rate plastic straining followed by creep tests were conducted to investigate the effect of prior plastic straining on the subsequent creep behavior of 304 stainless steel at room temperature. The effects of plastic strain and plastic strain-rate were delineated by a specially designed test procedure, and it is found that both factors have a strong influence on the subsequent creep deformation. A creep model combining the two factors is then developed. The predictions of the model are in good agreement with the test results.

An Assessment of the Method Used to Determine Activation Parameters in L12 Alloys

1998 ◽  
Vol 552 ◽  
Author(s):  
B. Matterstock ◽  
G. Saada ◽  
J. Bonneville ◽  
J. L Martin
Keyword(s):  
Mechanical Properties ◽  
Theoretical Analysis ◽  
Plastic Strain ◽  
Strain Rate ◽  
Characteristic Time ◽  
Constant Strain Rate ◽  
Activation Parameters ◽  
Plastic Strain Rate ◽  
Clear Indication ◽  
Load Relaxation

ABSTRACTThe characterisation of dislocation mechanisms in connection with macroscopic mechanical properties are usually performed through transient tests, such as strain-rate jumps, load relaxations or creep experiments. The present paper includes a careful and complete theoretical analysis of the relaxation and the creep kinetics. We experimentally show that the plastic strain-rate is continuous at the transition between constant strain-rate conditions and both load relaxation and creep test. The product of the plastic strain-rate at the onset of the transient test () with the characteristic time (tk) of the transient is found to be independent of , as theoretically expected. This is a clear indication that the assumptions underlying the theoretical analysis are relevant.

scholarly journals Effect of Stress-Relieving Heat Treatment on the High Strain Rate Dynamic Compressive Properties of Additively Manufactured Ti6Al4V (ELI)

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 653
Author(s):  
Amos Muiruri ◽  
Maina Maringa ◽  
Willie du Preez ◽  
Leonard Masu
Keyword(s):  
Plastic Strain ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Deformation Behaviour ◽  
Test System ◽  
Strain Rates ◽  
Stress Relieving ◽  
Strain Rate Compression

A study was undertaken on the compressive high strain rate properties and deformation behaviour of Direct Metal Laser-Sintered (DMLS) Ti6Al4V (ELI) parts in two separate forms: as-built (AB) and stress relieved (SR). The high strain rate compression tests were carried out using a Split Hopkinson Pressure Bar test system at ambient temperature. The average plastic strain rates attained by the system were 400 s−1 and 700 s−1. Comparative analyses of the performance (flow stresses and fracture strains) of AB and SR specimens were carried out based on the results obtained at these two plastic strain rates. Microstructural analyses were performed to study the failure mechanisms of the deformed specimens and fracture surfaces. Vickers microhardness test values were obtained before and after high strain rate compression testing. The results obtained in both cases showed the strain rate sensitivity of the stress-relieved samples to be higher in comparison to those of as-built ones, at the same value of true strain.

scholarly journals Analysis of Test System Misalignment in the Creep Test

1982 ◽  
Vol 104 (4) ◽  
pp. 280-284
Author(s):  
Han C. Wu ◽  
T. P. Wang
Keyword(s):  
Creep Strain ◽  
Creep Test ◽  
Test System ◽  
Neutral Axis ◽  
Strain Level ◽  
Initial Strain ◽  
Creep Tests ◽  
Test Sheet ◽  
Creep Stress ◽  
Creep Time

An analysis of test system misalignment is presented for the creep test. Sheet type rectangular 1100-0 aluminum specimens are used for discussion. It is found that the creep strain at the geometric centerline of the specimen is different than that at the neutral axis. However, this difference in the creep strain decreases with time. Generally, the effect of misalignment decreases with creep time. Creep tests conducted with long pullrods and large initial strain level (high creep stress) will tend to minimize the effect of misalignment.

Experimental Study of Uniaxial Compressive Strength of Gas Hydrate-Bearing Sediment at Constant Strain Rate

2012 ◽  
Author(s):  
Xiongfei Nie ◽  
Weiguo Liu ◽  
Yongchen Song ◽  
Jiafei Zhao ◽  
Rui Wang
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
Power Function ◽  
Uniaxial Compressive Strength ◽  
Gas Hydrate ◽  
Failure Time ◽  
Constant Strain Rate ◽  
Test System ◽  
Synthetic Gas ◽  
Compressive Tests

The uniaxial compressive tests are conducted on synthetic gas hydrate-bearing sediment samples by using the low-temperature high-pressure triaxial test system. The effects of the temperature, the strain rate and the failure time on the uniaxial compressive strength of hydrate sediment are measured. The results indicate that: (a) The uniaxial compressive strength is sensitive to the change of temperature and increases exponentially as temperature decreases. (b) The uniaxial compressive strength of hydrate sediment changes with the strain rate obviously, and increases with the strain rate increasing following a power function. (c) The uniaxial compressive strength increases with the failure time decreasing following a power function.

Transient Creep Behavior of γ-TiAl Polycrystals

1996 ◽  
Vol 460 ◽  
Author(s):  
B. Viguier ◽  
J. Bonneville ◽  
P. Spätig ◽  
J. L. Martin
Keyword(s):  
Plastic Strain ◽  
Strain Rate ◽  
Strain Hardening ◽  
Creep Behavior ◽  
Room Temperature ◽  
Constant Strain Rate ◽  
Transient Creep ◽  
Load Relaxation ◽  
Hardening Coefficient ◽  
Good Agreement

ABSTRACTTwo types of transient creep experiments performed along stress-strain curves are described and successfully applied to γ TiAl polycrystals at room temperature. They allow to determine activation volumes in good agreement with those measured through successive load relaxation tests. In addition, the combination of the latter method and the present ones provides relevant values of the plastic strain hardening coefficient. This latter parameter is found to exhibit similar values in transient as well as during constant strain rate tests.

A Modified Peric Model for Al-Mg Alloy Sheet with Rate-Independent Initial Yield Stress at Warm Temperatures

2019 ◽  
Vol 287 ◽  
pp. 3-7
Author(s):  
Yong Zhang ◽  
Qing Zhang ◽  
Yuan Tao Sun ◽  
Xian Rong Qin
Keyword(s):  
Flow Stress ◽  
Plastic Strain ◽  
Strain Rate ◽  
Yield Stress ◽  
Constitutive Models ◽  
Mg Alloy ◽  
Initial Yield Stress ◽  
Initial Yield ◽  
Rate Dependent ◽  
Dependent Flow

The constitutive modeling of aluminum alloy under warm forming conditions generally considers the influence of temperature and strain rate. It has been shown by published flow stress curves of Al-Mg alloy that there is nearly no effect of strain rate on initial yield stress at various temperatures. However, most constitutive models ignored this phenomenon and may lead to inaccurate description. In order to capture the rate-independent initial yield stress, Peric model is modified via introducing plastic strain to multiply the strain rate, for eliminating the effect of strain rate when the plastic strain is zero. Other constitutive models including the Wagoner, modified Hockett–Sherby and Peric are also considered and compared. The results show that the modified Peric model could not only describe the temperature-and rate-dependent flow stress, but also capture the rate-independent initial yield stress, while the Wagoner, modified Hockett–Sherby and Peric model can only describe the temperature-and rate-dependent flow stress. Moreover, the modified Peric model could obtain proper static yield stress more naturally, and this property may have potential applications in rate-dependent simulations.

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