scholarly journals Uniaxial Dynamic Compressive Behaviors of Hydraulic Asphalt Concrete under the Coupling Effect between Temperature and Strain Rate

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5348
Author(s):  
Rui Tang ◽  
Zhenpeng Yu ◽  
Guoqing Liu ◽  
Furong Li ◽  
Wenbin Tang
Keyword(s):  
Quantitative Analysis ◽  
Strain Rate ◽  
Temperature Effect ◽  
Asphalt Concrete ◽  
Brittle Failure ◽  
Failure Modes ◽  
Strain Softening ◽  
Coupling Effect ◽  
Peak Stress ◽  
Stress Strain

To investigate the compressive dynamic properties of hydraulic asphalt concrete under various temperatures, four temperatures and four strain rates have been set to perform the uniaxial compression experiments using hydraulic servo machine in this paper. The influence of temperature and strain rate on the failure modes, stress-strain curves and mechanical characteristic parameters of hydraulic asphalt concrete is analyzed and the results reveal that the failure modes and stress-strain curves have significant temperature effect. When the temperature is between −20 °C and 0 °C, the failure mode is dominated by brittle failure of asphalt binder, and hydraulic asphalt concrete shows obvious strain softening. With the addition of temperature, the failure modes of specimens are transferred from brittle failure to ductile failure since the asphalt changes from elastic-brittleness to viscoelasticity. Influenced by temperature effect, the compressive stress-strain curves of hydraulic asphalt concrete show strain hardening while the peak stress of hydraulic asphalt concrete is obviously decreased, and the variation coefficient of peak stress has a power relation with temperature. With successive increases in strain rate, the stress-strain curves of hydraulic asphalt concrete gradually are transferred from strain hardening to strain softening. The peak stress and stiffness modulus of specimens under compression gradually increase, and the dynamic increase factor of peak stress is linearly related with the logarithm value of strain rate after dimensionless treatment. In terms of the quantitative analysis of the experimental data, two relationship models of the coupling effect between temperature and strain rate are proposed. The proposed models have good applicability to the quantitative analysis of the experimental results in the manuscript. This paper offers important insights into the application and development of hydraulic asphalt concrete in hydraulic engineering.

AN EXPERIMENTAL STUDY ON THE IMPACT DEFORMATION AND THE STRAIN RATE SENSITIVITY IN SOME STRUCTURAL ADHESIVES

2008 ◽  
Vol 22 (31n32) ◽  
pp. 5590-5595 ◽  
Author(s):  
TOSHIMASA NAGAI ◽  
TAKESHI IWAMOTO ◽  
TOSHIYUKI SAWA ◽  
YASUHISA SEKIGUCHI ◽  
HIDEAKI KURAMOTO ◽  
...  
Keyword(s):  
Strain Rate ◽  
Inelastic Deformation ◽  
Strain Softening ◽  
Peak Stress ◽  
Stress Strain ◽  
Structural Adhesives ◽  
Strain Behavior ◽  
Impact Deformation ◽  
The Impact ◽  
Softening Stage

The impact deformation behavior and the strain sensitivity of structural adhesives are experimentally investigated by using INSTRON-type universal testing machine and split Hopkinson pressure bar apparatus. The experimental results show some fundamental features of the typical compressive stress-strain behavior of polymers with linear elastic and nonlinear inelastic deformation stages. In the inelastic deformation, the peak stress, and the strain-softening stage after the peak can be observed at the entire range of strain-rate from 10-4 to 103 /s. In addition, it can be found that the relationship between the peak stress at the strain-softening stage and strain-rate for a semi-logarithm curve is linear in a range of low strain rate, however, that becomes nonlinear at high strain rate. Finally, some constitutive models try to be applied for to describe the stress-strain behavior of structural adhesives.

scholarly journals Transient Solutions for One-Dimensional Problems With Strain Softening

1987 ◽  
Vol 54 (3) ◽  
pp. 513-518 ◽  
Author(s):  
T. Belytschko ◽  
Xiao-Jun Wang ◽  
Z. P. Bazant ◽  
Y. Hyun
Keyword(s):  
Strain Rate ◽  
Closed Form ◽  
Transient Response ◽  
Softening Point ◽  
Strain Softening ◽  
Stress Strain ◽  
One Dimensional ◽  
Closed Form Solutions ◽  
Transient Solutions

Closed-form solutions are presented for the transient response of rods in which strain softening occurs and the stress-strain laws exhibit nonvanishing stresses after the strain-softening regime. It is found that the appearance of any strain softening results in an infinite strain rate if the material is inviscid. For a stress-strain law with a monotonically decreasing stress the strains are infinite also. If the stress increases after the strain-softening portion, the strains remain finite and the strain-softening point moves through the rod.

Spall damage of a mild carbon steel: Effects of peak stress, strain rate and pulse duration

2016 ◽  
Vol 660 ◽  
pp. 139-147 ◽  
Author(s):  
C. Li ◽  
B. Li ◽  
J.Y. Huang ◽  
H.H. Ma ◽  
M.H. Zhu ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Strain Rate ◽  
Pulse Duration ◽  
Peak Stress ◽  
Stress Strain ◽  
Mild Carbon Steel ◽  
Spall Damage

scholarly journals Hot Deformation Behavior and Constitutive Modeling of H13-Mod Steel

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 846 ◽  
Author(s):  
Changmin Li ◽  
Yuan Liu ◽  
Yuanbiao Tan ◽  
Fei Zhao
Keyword(s):  
Constitutive Equation ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
High Strain ◽  
Flow Behavior ◽  
Peak Stress ◽  
Strain Rates ◽  
Hot Deformation Behavior ◽  
Stress Strain

The H13-mod steel optimized by composition and heat treatment has reached the performance index of the shield machine hob. The hot deformation behavior of the H13-mod steel was investigated by compression tests in the temperature range from 900 to 1150 °C and the strain rate range from 0.01 to 10 s−1. The true stress-strain curve showed that the rising stress at the beginning of deformation was mainly caused by work hardening. After the peak stress was attained, the curve drop and the flow softening phenomenon became more obvious at low strain rates. The flow behavior of the H13-mod steel was predicted by a strain-compensated Arrhenius-type constitutive equation. The relationship between the material constant in the Arrhenius-type constitutive equation and the true strain was established by a sixth-order polynomial. The correlation coefficient between the experimental value and the predicted value reached 0.987, which indicated that the constitutive equation can accurately estimate the flow stress during the deformation process. A good linear correlation was achieved between the peak stress (strain), critical stress (strain) and the Zener‒Hollomon parameters. The processing maps of the H13-mod steel under different strains were established. The instability region was mainly concentrated in the high-strain-rate region; however, the microstructure did not show any evidence of instability at high temperatures and high strain rates. Combined with the microstructure and electron backscattered diffraction (EBSD) test results under different deformations, the optimum hot working parameters were concluded to be 998–1026 °C and 0.01–0.02 s−1 and 1140–1150 °C and 0.01–0.057 s−1.

scholarly journals Performance of Circular Concrete-Filled FRP-Grooved Steel Composite Tube Columns under Axial Compression

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3638
Author(s):  
Kunting Miao ◽  
Yang Wei ◽  
Xi Zhang ◽  
Kaiqi Zheng ◽  
Fenghui Dong
Keyword(s):  
Failure Modes ◽  
Linear Part ◽  
Strain Curve ◽  
Peak Stress ◽  
Steel Tube ◽  
Peak Strain ◽  
Test Results ◽  
Stress Strain ◽  
Composite Tube ◽  
Steel Composite

A new structure termed “concrete-filled FRP-grooved steel composite tube (CFGCT) column” is proposed, which is composed of a stress-released steel tube (i.e., grooved steel tube), fiber-reinforced polymer (FRP) and concrete. Axial load tests were carried out on twenty-four specimens to investigate the constraint effect of this structure. Three main experimental variables were considered: the steel tube thickness, the FRP type, and the FRP layer. The failure modes, stress-strain relationships and the effect of the main experimental variables were discussed. The stress-strain curves of this new structure are composed of an initial linear part, a nonlinear transition part, a strengthening part and a residual part. The test results demonstrate that the bearing capacity of the structure was improved, and that the mechanical mechanism of the structure was simplified due to the stress-released grooves. Based on the test results and previous studies, formulas for calculating the ultimate stress (fcu), ultimate strain (εcu), peak stress (fcc) and peak strain (εcc) were proposed. In addition, models for predicting the stress-strain curves of CFGCT columns were put forward, and the models could precisely simulate the stress-strain curve of this new composite structure. Hence, this study indicates that a structure composed of FRP and stress-released steel tube can effectively constrain concrete.

The Combined Effects of Hydrostatic Pressure and Strain-Rate on the Compressive Properties of a Laminated, Multi-Directional, Graphite/Epoxy Thick-Composite

1998 ◽  
Vol 32 (1) ◽  
pp. 49-67 ◽  
Author(s):  
K. D. Pae ◽  
K. S. Carlson
Keyword(s):  
Hydrostatic Pressure ◽  
Strain Rate ◽  
Coupling Effect ◽  
Experimental Studies ◽  
Strain Rates ◽  
Combined Effects ◽  
Compressive Properties ◽  
Stress Strain ◽  
Simultaneous Application ◽  
Low Strain Rate

Experimental studies of the combined effects of hydrostatic pressure and strain-rate on the compressive properties of a laminated, multi-directional graphite fiber/epoxy matrix thick-composite have been made. It has been determined that the compressive stress-strain behavior of the thick-composite is dependent significantly on hydrostatic pressure and strain-rate. The hydrostatic pressure ( P) applied was 1 bar, 1 kbar, 2 kbar, and 3 kbar and the average strain-rates (ε) used for the studies were 6.51 x 10−2%/s (quasi-static or low strain-rate) and 1.27%/s (high strain-rate). The compressive properties—namely the Young's modulus ( E), the yield strength (σγ) when one occurred, the ultimate strength (σ U) or the fracture strength (σ f), and the fracture strain (ε f)—were determined as a function of P and ε. The E increased bilinearly with P at the low and the high is with the discontinuity point located at ~2 kbar. It is particularly important to note that there was a coupling effect of P and ε on E of the thick-composite. The coupling effect was that the value of E under simultaneous application of P and the high ε was greater than the sum of the values of E under separate application of P and the high ε. The multi-directional thick-composite behaved like a brittle material, exhibiting only linear elastic stress-strain curves, under 1 bar and the low strain-rate. It, however, underwent 2% off-set yielding when P ≥ 2 kbar under the low and the high ε S. The σ F remained virtually unchanged at each pressure level, regardless of strain rates used but the σ F decreased with ε.

Experimental Study on Post-Peak Failure Behavior of Rock Masses with Persistent Joint

2014 ◽  
Vol 580-583 ◽  
pp. 610-613 ◽  
Author(s):  
Lei Wang ◽  
Jiang Yu ◽  
Xue Hua
Keyword(s):  
Inclination Angle ◽  
Failure Modes ◽  
Research Result ◽  
Peak Stress ◽  
Jointed Rock ◽  
Failure Behavior ◽  
Uniaxial Compression Test ◽  
Rock Masses ◽  
Stress Strain ◽  
Joint Inclination

The uniaxial compression test on pre-existing persistent jointed rock cylindrical standard specimen made by high stiffness servo control testing machine, systematic researched the relationship between jointed rock post-peak stress-strain curve, the destroy form of rock masses with dip angles of persistent joints. And the results reveal that: (1) The post-peak stress - strain curves of specimens with joint inclination angle of 15°and complete specimens are basically the same, but the difference of post-peak stress - strain curves of specimens with the joint inclination angle from 30°to 60°and complete specimens is vary greatly; (2) The post-peak failure modes of specimen change with different joint inclination. The research result can reflect mechanics and deformation and damage characteristics under uniaxial compressive loading in the phase of post-peak of rock masses with different dip angle pre-existing persistent joints.

Study on Constitutive Equation of 7085 Aluminum Alloy under High Deformation Temperature

2015 ◽  
Vol 1095 ◽  
pp. 579-582
Author(s):  
Rui Bin Mei ◽  
Bo Zhang ◽  
B. Cai ◽  
X.Y. Zhang ◽  
Z.T. Zou ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Flow Stress ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Deformation Temperature ◽  
Peak Stress ◽  
Strain Rate Range ◽  
Peak Strain ◽  
Stress Strain ◽  
Deformation Velocity

The flow stress behavior of the 7085 aluminum alloy was studied through single-pass compression experiment by using MMS-300 simulator within temperature range of 300-450°C and strain rate range of 0.01-10s-1. Dynamic recrystallization occurs in hot compression of 7085 alloy and the stress-strain curves are presented as wave with higher deformation temperature and strain rate. Increasing of deformation velocity and reducing temperature results in higher peak stress. Then a mathematical model has been developed to predict the stress-strain curves based on phenomenological representation of the curves and the traditional theories for constitutive equations which incorporate the power law. The constitutive equation expressed in terms of peak stress, peak strain and additional parameters to predict flow stress. The stress-strain curves of 7085 alloy predicted by this model are in good agreement with experimental results.

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