Compressive strength and creep behavior of hydrate-consolidated sand

1990 ◽  
Vol 27 (2) ◽  
pp. 255-258 ◽  
Author(s):  
I. Cameron ◽  
Y. P. Handa ◽  
T. H. W. Baker
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Strain Rate ◽  
Creep Behavior ◽  
Gas Hydrates ◽  
Peak Stress ◽  
Strain Rates ◽  
Stress Strain ◽  
Frozen Sand ◽  
Cylindrical Samples

Cylindrical samples of sand consolidated with tetrahydrofuran hydrate were tested for their compressive strength and creep behavior under uniaxial compression. The samples were 15 cm in length and 7.5 cm in diameter and were tested at −10 °C. The results, when combined with our previous measurements on similar samples at −6 °C, show that the material becomes stronger by about 10% with decrease in temperature; otherwise, the slopes of the peak stress – strain rate curves are the same. These results are similar to those of sand consolidated with ice, except that in the latter case the increase in strength over the same temperature range is about 30%. Furthermore, the slope of the peak stress – strain rate curve for the hydrate-consolidated sand is almost zero, whereas for the ice-consolidated sand it is quite steep. Consequently, at strain rates below 10−5 s−1 the hydrate-consolidated sand is stronger, whereas at strain rates above 10−5 s−1 the ice-consolidated sand is the stronger material. Noticeable differences were also observed in the creep behavior of the hydrate- and ice-consolidated sands. At −10 °C, ice-consolidated sand failed in about 15 h under a stress of about 7 MPa, whereas hydrate-consolidated sand failed after 52.3 h under a stress of 12.2 MPa and some samples did not fail even after 540 h when subjected to a stress of 9.3 MPa. Key words: gas hydrates, ice, frozen sand, mechanical properties, compressive strength, creep behavior.

Strength of frozen sand containing tetrahydrofuran hydrate

1989 ◽  
Vol 26 (3) ◽  
pp. 479-483 ◽  
Author(s):  
V. R. Parameswaran ◽  
M. Paradis ◽  
Y. P. Handa
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Strain Rate ◽  
Creep Behavior ◽  
Peak Stress ◽  
Strain Rates ◽  
Rate Region ◽  
Frozen Sand ◽  
Cylindrical Samples ◽  
Low Strain Rate

Cylindrical samples of frozen sand containing tetrahydrofuran hydrate were tested under uniaxial compression at 267 K and strain rates between 10−6 and 10−3 s−1. In the low strain rate region the compressive strength of the samples was higher than that of frozen sand containing ice. For example, at 267 K and a strain rate of 10−6 s−1 the peak stress for the frozen sand containing hydrate was about 16 MPa, whereas the corresponding value for the frozen sand containing ice was only 10.5 MPa. The strain rate dependence of stress for the frozen sand containing hydrate was much smaller than that of frozen sand containing ice, so that at higher strain rates the compressive strengths of the two materials become almost the same. Key words: tetrahydrofuran hydrate, frozen sand, mechanical properties, compressive strength, creep behavior.

Experimental study on stress-strain curves of seawater sea-sand concrete under uniaxial compression with different strain rates

2020 ◽  
pp. 136943322095876
Author(s):  
Kaijian Zhang ◽  
Jianzhuang Xiao ◽  
Qingtian Zhang
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Strain Rate ◽  
Uniaxial Compression ◽  
Peak Stress ◽  
Ultimate Strain ◽  
Strain Rates ◽  
Peak Strain ◽  
Stress Strain ◽  
Sea Sand

In order to investigate the mechanical properties of seawater sea-sand concrete (SSC) under uniaxial compression, the SSC prisms with different mix proportions are designed and prepared, and the compressive strength and stress-strain curves under uniaxial compression are tested, in which five loading strain rates 10−5/s, 10−4/s, 10−3/s, 10−2/s, and 10−1/s are selected. The failure patterns of the SSC specimens under different strain rates are discussed, and the peak stress, peak strain (strain at the peak stress), elastic modulus, and ultimate strain are analyzed. The influence of the strain rate and the shell particle content on the stress-strain curves is intensively evaluated. It shows that the peak stress and elastic modulus increase with an increasing strain rate while the peak strain and ultimate strain have no obvious trend. Additionally, the shell particles seem to have contributions to the increase of the compressive strength of SSC base on the test results of cube and prism specimens, but further considerations about this phenomenon are necessary. Finally, the dynamic increase factor (DIF) of characteristic indices of SSC is put forward.

scholarly journals Static Mechanical Properties of Expanded Polypropylene Crushable Foam

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 249
Author(s):  
Przemysław Rumianek ◽  
Tomasz Dobosz ◽  
Radosław Nowak ◽  
Piotr Dziewit ◽  
Andrzej Aromiński
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Strain Rate ◽  
Energy Absorption ◽  
Experimental Tests ◽  
Absorption Capacity ◽  
Strain Rates ◽  
Foam Density ◽  
Energy Absorption Capacity ◽  
Closed Cell

Closed-cell expanded polypropylene (EPP) foam is commonly used in car bumpers for the purpose of absorbing energy impacts. Characterization of the foam’s mechanical properties at varying strain rates is essential for selecting the proper material used as a protective structure in dynamic loading application. The aim of the study was to investigate the influence of loading strain rate, material density, and microstructure on compressive strength and energy absorption capacity for closed-cell polymeric foams. We performed quasi-static compressive strength tests with strain rates in the range of 0.2 to 25 mm/s, using a hydraulically controlled material testing system (MTS) for different foam densities in the range 20 g/dm3 to 220 g/dm3. The above tests were carried out as numerical simulation using ABAQUS software. The verification of the properties was carried out on the basis of experimental tests and simulations performed using the finite element method. The method of modelling the structure of the tested sample has an impact on the stress values. Experimental tests were performed for various loads and at various initial temperatures of the tested sample. We found that increasing both the strain rate of loading and foam density raised the compressive strength and energy absorption capacity. Increasing the ambient and tested sample temperature caused a decrease in compressive strength and energy absorption capacity. For the same foam density, differences in foam microstructures were causing differences in strength and energy absorption capacity when testing at the same loading strain rate. To sum up, tuning the microstructure of foams could be used to acquire desired global materials properties. Precise material description extends the possibility of using EPP foams in various applications.

scholarly journals Dynamic Constitutive Model of Ultra-High Molecular Weight Polyethylene (UHMWPE): Considering the Temperature and Strain Rate Effects

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1561 ◽  
Author(s):  
Kebin Zhang ◽  
Wenbin Li ◽  
Yu Zheng ◽  
Wenjin Yao ◽  
Changfang Zhao
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Plastic Material ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Ballistic Performance ◽  
Stress Strain ◽  
Different Temperatures

The temperature and strain rate significantly affect the ballistic performance of UHMWPE, but the deformation of UHMWPE under thermo-mechanical coupling has been rarely studied. To investigate the influences of the temperature and the strain rate on the mechanical properties of UHMWPE, a Split Hopkinson Pressure Bar (SHPB) apparatus was used to conduct uniaxial compression experiments on UHMWPE. The stress–strain curves of UHMWPE were obtained at temperatures of 20–100 °C and strain rates of 1300–4300 s−1. Based on the experimental results, the UHMWPE belongs to viscoelastic–plastic material, and a hardening effect occurs once UHMWPE enters the plastic zone. By comparing the stress–strain curves at different temperatures and strain rates, it was found that UHMWPE exhibits strain rate strengthening and temperature softening effects. By modifying the Sherwood–Frost model, a constitutive model was established to describe the dynamic mechanical properties of UHMWPE at different temperatures. The results calculated using the constitutive model were in good agreement with the experimental data. This study provides a reference for the design of UHMWPE as a ballistic-resistant material.

scholarly journals Deformation behaviour and strength of frozen sand

1980 ◽  
Vol 17 (1) ◽  
pp. 74-88 ◽  
Author(s):  
V. R. Parameswaran
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
Deformation Behaviour ◽  
Unfrozen Water ◽  
Strain Rates ◽  
Linear Extrapolation ◽  
Compression Tests ◽  
Unconfined Compression ◽  
Ottawa Sand ◽  
Frozen Sand

Uniaxial unconfined compression tests were carried out on frozen saturated Ottawa sand containing about 20% by weight of water, at temperatures between −2 and − 15°C, and at strain rates varying between 10−7 and 10−2 s−1. The compressive strength and the initial tangent modulus increased with increasing strain rate and with decreasing temperature. At −2°C, values of strength and modulus were considerably lower than those predicted by linear extrapolation of the values observed at lower temperatures, on a log–log scale. This could be due to the presence of unfrozen water in the samples at −2°C.

scholarly journals Investigation on Mechanical Properties of GH4720Li at High Strain Rates at Wider Temperature Range

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Jie Chen ◽  
Haifeng Zhang ◽  
Yunlong Zhang ◽  
Hongtao Zhang ◽  
Qingxiang Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
True Stress ◽  
Strain Rates ◽  
Hot Compression Test ◽  
Strength And Plasticity ◽  
Low Strain Rate

In this paper, the dynamic mechanical properties of GH4720Li nickel-base alloy under a large temperature range and high and low strain rates were studied by the hot compression test. The difference of mechanical properties of GH4720Li alloy under high and low strain rates was analyzed from the perspective of microstructure. The hot compression test experimental results showed that the true stress of GH4720Li alloy decreased at a low strain rate as the trial temperature elevated. Nevertheless, it was abnormal that the true stress increased at high strain rate condition as temperature elevated. By comparing the microstructure under high and low strain rates, it was found that the precipitates under low strain conditions contained a large amount of Cr (Mo). However, the content of Cr (Mo) in the precipitates at a high strain rate decreased, while the content of Fe increased. It would be concluded that Cr (Mo) would reduce the compressive strength and plasticity of GH4720Li alloy, while Fe would increase the compressive strength and plasticity of GH4720Li alloy. In addition, under the condition of a low strain rate, the shape of Cr (Mo) precipitates obtained at 20°C was lamellar, but it was spherical at 800°C. The compressive strength of GH4720Li composites with lamellar precipitates was higher than that of spherical precipitates.

High Strain Rate Mechanical Properties of SAC-Q Between -65°C and +200°C After Exposure to Isothermal Aging

2020 ◽  
Author(s):  
Pradeep Lall ◽  
Vishal Mehta ◽  
Jeff Suhling ◽  
Ken Blecker
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Isothermal Aging ◽  
High Strain ◽  
Strain Rates ◽  
Solder Alloys ◽  
Stress Strain ◽  
Wide Range ◽  
Operating Temperatures ◽  
Electronic Parts

Abstract In many industries, such as automotive, oil and gas, aerospace, medical technologies, electronic parts can often be exposed to high strain loads during shocks, vibrations and drop-impact conditions. Such electronic parts can often be subjected to extreme low and high temperatures ranging from −65°C to 200°C. Also, these electronic devices can be subjected to strain rates of 1 to 100 per second in the critical environment. Recently, many doped SAC solder alloys are being introduced in the electronic component including SAC-Q, SAC-R, Innolot. SAC-Q is made with addition of Bi in Sn-Ag-Cu composition. Mechanical characteristic results and data for lead-free solder alloys are extremely important for optimizing electronic package reliability, at high temperature storage and elevated strain rates. Furthermore, the mechanical properties of solder alloys can be changed significantly due to a thermal aging, which is causing modification of microstructure. Data for the SAC-Q solder alloy with a high temp aging and testing at extreme low to high operating temperatures are not available. SAC-Q material was tested and analyzed for this study at range of operating temperatures of −65°C to 200°C and at a strain rate up to 75 per second. After the specimens were manufactured and reflowed, specimens were stored at 100°C for the isothermal aging for up to 90 days, before tensile tests were carried out at different operating temperatures. For the wide range of strain rates and test temperatures, stress-strain curves are established. In addition, the measured experimental results and data were fitted to the Anand viscoplasticity model and the Anand constants were calculated by estimating the stress-strain behavior measured in the wide range of operating temperatures and strain rates.

Application of Shape Factor to Mechanical Behavior of Thermal Interface Pads and Putties

2021 ◽  
Author(s):  
Karl F. Schoch ◽  
Philip Panackal ◽  
M. Garrett Bimstefer ◽  
Amanda Brocki ◽  
Daniel Urban
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Shape Factor ◽  
Compressive Strain ◽  
Peak Stress ◽  
Temperature Cycling ◽  
Strain Rates ◽  
Initial Shape ◽  
Thermal Interface ◽  
Shape Factors

Abstract Thermal interface materials (TIMs) are an essential part of managing thermal performance of electronic assemblies. Knowledge of the mechanical properties of these materials is required in order to have a robust design that will perform as required over the life of the product, including many thermal cycles, without causing damage to electrical components. In this paper, we report on mechanical properties of three putty TIMs and four pad TIMs, showing that the stiffness of the TIMs is proportional to the square of the initial shape factor over the range of shape factors from 1 to 18. Since the putties can flow more readily under pressure than the pads, the putties had a lower measured stiffness at a given shape factor compared to the pads. From these relationships, designers can predict loads with various geometries (i.e. shape factors) and loading rates (i.e. shock loading vs. temperature cycling) which can impact their design. While all of the materials were tested at compressive strain rates of 20 to 70% strain/minute, one putty was also tested at a 10x higher rate to determine the effect of a relatively high strain rate on the peak stress. In that case, the peak stress was approximately 3x higher than measured at the lower strain rates. However, the relaxed load at each strain rate tested was unaffected by strain rate, indicating that hardware assembly conditions can be adjusted to minimize stress on components and yet, still achieve an interface having low thermal resistance.

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.

Measurement of Mechanical Properties of St 37 Material at High Strain Rates Using a Split Hopkinson Pressure Bar

2014 ◽  
Vol 660 ◽  
pp. 562-566 ◽  
Author(s):  
Akbar Afdhal ◽  
Leonardo Gunawan ◽  
Sigit P. Santosa ◽  
Ichsan Setya Putra ◽  
Hoon Huh
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Test Specimen ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Stress Strain ◽  
Split Hopkinson ◽  
Pressure Bar

The dynamic mechanical properties of a material are important keys to investigate the impact characteristic of a structure such as a crash box. For some materials, the stress-strain relationships at high strain rate loadings are different than that at the static condition. These mechanical properties depend on the strain rate of the loadings, and hence an appropriate testing technique is required to measure them. To measure the mechanical properties of a material at high strain rates, ranging from 500 s-1 to 10000 s-1, a Split Hopkinson Pressure Bar is commonly used. In the measurements, strain pulses are generated in the bars system, and pulses being reflected and transmitted by a test specimen in the bar system are measured. The stress-strain curves as the material properties of the test specimen are obtained by processing the measured reflected and transmitted pulses. This paper presents the measurements of the mechanical properties of St 37 mild steel at several strain rates using a Split Hopkinson Pressure Bar. The stress-strain curves obtained in the measurement were curve fitted using the Power Law. The results show that the strength of St 37 material increases as the strain rate increases.

Sign in / Sign up

Export Citation Format

Share Document