Journal articles: 'High strain-rates tests'

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Piao, Ming Jun, Hoon Huh, and Ik Jin Lee. "Characterization of Hardening Behavior at Ultra-High Strain Rate, Large Strain, and High Temperature." Key Engineering Materials 725 (December 2016): 138–42. http://dx.doi.org/10.4028/www.scientific.net/kem.725.138.

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This paper is concerned with the characterization of the OFHC copper flow stress at strain rates ranging from 10−3 s−1 to 106 s−1 considering the large strain and high temperature effects. Several uniaxial material tests with OFHC copper are performed at a wide range of strain rates from 10−3 s−1 to 103 s−1 by using a INSTRON 5583, a High Speed Material Testing Machine (HSMTM), and a tension split Hopkinson pressure bar. In order to consider the thermal softening effect, tensile tests at 25°C and 200°C are performed at strain rates of 10−3 s−1,101 s−1, and 102 s−1. A modified thermal softening model is considered for the accurate application of the thermal softening effect at high strain rates. The large strain behavior is challenged by using the swift power law model. The high strain rates behavior is fitted with the Lim–Huh model. The hardening curves are evaluated by comparing the final shape of the projectile from numerical simulation results with the Taylor impact tests.

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Cadoni, Ezio, George Solomos, and Carlo Albertini. "Concrete behaviour in direct tension tests at high strain rates." Magazine of Concrete Research 65, no. 11 (June 2013): 660–72. http://dx.doi.org/10.1680/macr.12.00175.

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Younes, Ayham, Vignaesh Sankaran, André Seidel, Martin Waldmann, Chokri Cherif, and Jan Hausding. "Stress-strain behavior of carbon filament yarns under high strain rates." Textile Research Journal 82, no. 7 (February 13, 2012): 685–99. http://dx.doi.org/10.1177/0040517511433151.

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Fiber-reinforced composites used in numerous technical applications have to meet the ever increasing safety requirements. Resistance to extreme stress under high velocity impact loads assumes even greater significance. Previous studies on the behavior of fiber-reinforced composites under impact loads provide little insight about the properties of filament yarns, a basis for many composite applications. Hence this paper focuses on the development of a suitable test method for performing high speed tensile tests on all filament yarn types, and the acquisition and analysis of the test results. This will enable the derivation of material models for their usage in the field of composites applications. Initially, the widely used carbon fiber filament yarns have been tested. The conclusive test results with a reduced yarn clamp mass and high stiffness of the test apparatus indicate that tensile strength and modulus of elasticity of carbon filament yarns increase with higher strain rates.

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Mentl, Vaclav, and Josef Bystricky. "Compression Tests of High Strength Steels." Advanced Materials Research 59 (December 2008): 293–98. http://dx.doi.org/10.4028/www.scientific.net/amr.59.293.

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Mathematical modelling and virtual testing of components and structures represent a useful and economic tool for design and safety assessment. The basic mechanical properties which can be found in material standards are not relevant in cases where the real service conditions differ from those applied during standardised testing. Thus e.g. mechanical behaviour at higher strain rates can be interesting for the car components when the simulation of crash situations is used during structure development. The dynamic compression tests are usually performed by means of drop towers, by means of high speed hydraulic testing machines or Hopkinson bar method. At the Mechanical Testing Laboratory of the SKODA Research Inst. in Pilsen, Czech Republic, an instrumentation of Charpy pendulum testing machine was realised in order that it was possible to perfom dynamic compression tests, [1], and the compatibility of obtained results in comparison with traditional impact compression tests was verified within the round–robin carried out by TC5 ESIS Sub-Committee on “Mechanical Testing at Intermediate Strain Rates“, [2]. A new striking tup and load measurement system were designed and callibrated. At the same time, a new software was developed which makes it possible to evaluate the test force-deformation record. The goal of this study was 1. to check the possibility of compression testing of high strength materilas by mens of Charpy pendulum, and 2. to study the strain rate influence on basic mechanical properties.

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Park, Chung Hee, Seh Wan Jeong, Hoon Huh, and Jung Su Park. "Material Behaviors of PBX Simulant with Various Strain Rates." Key Engineering Materials 535-536 (January 2013): 117–20. http://dx.doi.org/10.4028/www.scientific.net/kem.535-536.117.

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This paper is concerned with the material behaviors of PBX(Polymer Bonded eXplosive) simulant at various strain rates ranging from 0.0001/sec to 3150/sec. Material behaviors of PBX at the high strain rates are important in the prediction of deformation modes of PBX in a warhead which undergoes severe impact loading. Inert PBX stimulant which has analogous material behaviors with PBX was utilized for material tests due to safety issues. Uniaxial compressive tests at quasi-static and intermediate strain rates were conducted with cylindrical specimen using a dynamic materials testing machine, INSTRON 8801. Uniaxial compressive tests at high strain rates ranging from 1200/sec to 3150/sec were conducted using a split Hopkinson pressure bar. Deformation behaviors were investigated using captured images obtained from a high-speed camera. The strain hardening behaviors of PBX simulant were formulated by proposed strain rate-dependent strain hardening model.

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Singh, Nilamber Kumar, Ezio Cadoni, Maloy K. Singha, and Narinder K. Gupta. "Mechanical Behavior of Advanced High Strength Steel at High Strain Rates." Applied Mechanics and Materials 82 (July 2011): 178–83. http://dx.doi.org/10.4028/www.scientific.net/amm.82.178.

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This paper presents the mechanical behavior of advanced high strength steel, Dual Phase 1200 steel (DP1200) at high strain rates (250s-1- 750s-1) under tensile loading. The mechanical behavior of materials depends on the loading rates. The accurate knowledge of the mechanical behavior of materials at high strain rates is essential in order to improve the safety against crash, impacts and blast loads. High strain rate experiments are performed on modified Hopkinson bar (MHB) apparatus; however, some quasi-static (0.001s-1) tests are also conducted on electromechanical universal testing machine at tensile loads. Based on the experimental results, the material parameters of the existing Cowper-Symonds and Johnson-Cook models are determined. These models fit the experimental data well and hence can be recommended for the numerical simulation of the problems involving this material at high strain rates.

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Meyer, Lothar W., Shawky Abdel-Malek, and Norman Herzig. "Experimental Methods for Characterizing of Sheet Metals at High Strain Rates." Key Engineering Materials 473 (March 2011): 474–81. http://dx.doi.org/10.4028/www.scientific.net/kem.473.474.

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Beside tension tests and measuring of Lankford coefficients (r-values), compression tests on small cubes in the sheet plane over a wide range of strain rates are also performed using special devices. The material behavior under shear loading is measured according to Miyauchi using appropriate equipment with the application of optical measurement of speckle strain field. A biaxial tension/tension stress state can be realized in the layer compression test. Through the compression, shear and layer compression tests, large deformations are reached, which can not be measured in the tension test due to necking. These four test types are performed not only quasi-statically but also quasi-dynamically on a servo hydraulic machine and under impact loading in a drop weight machine and rotary tensile impact tester (flywheel) with a precise measurement of force and displacement to determine the strain rate dependency of the investigated materials. Extra points of the yield loci can be measured in the plane strain tension test using a specimen ratio of B/L ≥ 20.

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Piao, Ming Jun, Chung Hee Park, Hoon Huh, and Ik Jin Lee. "Validation of Dynamic Hardening Models with Taylor Impact Tests at High Strain Rates." Key Engineering Materials 626 (August 2014): 389–96. http://dx.doi.org/10.4028/www.scientific.net/kem.626.389.

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This paper is concerned with the hardening behavior of 4340 steel at high strain rates from 104s-1to 106s-1. Tension tests were conducted using Instron 5583, HSMTM and SHPB testing machines at a wide range of strain rate from 10-3s-1to 103s-1. Three different impact velocities were performed for the Taylor impact tests to evaluate the reliability of Johnson–Cook model, modified Johnson–Cook model, modified Khan–Huang model, and Lim–Huh model at high strain rates for 4340 steel.

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Lei, S., Y. C. Shin, and F. P. Incropera. "Material Constitutive Modeling Under High Strain Rates and Temperatures Through Orthogonal Machining Tests." Journal of Manufacturing Science and Engineering 121, no. 4 (November 1, 1999): 577–85. http://dx.doi.org/10.1115/1.2833062.

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This paper presents a procedure to characterize deformation behavior applicable to various engineering materials in machining processes. Orthogonal machining tests are used to obtain the relationship between shear stress, strain, strain rate and temperature. Shear plane temperature is measured by an infrared thermal imaging system and compared with the Loewen and Shaw model. A new procedure to determine strain rate in the shear zone is proposed based on a triangular shear zone model and grain boundary determined by optical microscopy. Finally, a constitutive model for a low carbon steel, determined by the procedure, is presented and compared with existing results.

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Rey-de-Pedraza, V., F. Gálvez, and D. Cendón Franco. "Measurement of fracture energy of concrete at high strain rates." EPJ Web of Conferences 183 (2018): 02065. http://dx.doi.org/10.1051/epjconf/201818302065.

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The Hopkinson Bar has been widely used by many researchers for the analysis of dynamic properties of different brittle materials and, due to its great interest, for the study of concrete. In concrete structures subjected to high velocity impacts, initial compression pulses travel through the material leading to tensile stresses when they reach a free surface. These tensile efforts are the main cause of concrete fracture due to its low tensile strength compared to the compressive one. This is the reason why dynamic tests in concrete are becoming of great interest and are mostly focused in obtaining tensile fracture properties. Apart form the dynamic tensile strength, which has been widely studied by many authors in the last decades, the dynamic fracture energy presents an increased difficulty and so not too much experimental information can be found in literature. Moreover, up to date there is not a clear methodology proposed in order to obtain this parameter in an accurate way. In this work a new methodology for measuring the dynamic fracture energy is proposed by using the Hopkinson Bar technique. Initial tests for a conventional concrete have been carried out and the results for the dynamic fracture energy of concrete at different strain rates are presented.

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Williams, Orla, Simon Taylor, Edward Lester, Sam Kingman, Donald Giddings, and Carol Eastwick. "Applicability of Mechanical Tests for Biomass Pellet Characterisation for Bioenergy Applications." Materials 11, no. 8 (July 31, 2018): 1329. http://dx.doi.org/10.3390/ma11081329.

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In this paper, the applicability of mechanical tests for biomass pellet characterisation was investigated. Pellet durability, quasi-static (low strain rate), and dynamic (high strain rate) mechanical tests were applied to mixed wood, eucalyptus, sunflower, miscanthus, and steam exploded and microwaved pellets, and compared to their Hardgrove Grindability Index (HGI), and milling energies for knife and ring-roller mills. The dynamic mechanical response of biomass pellets was obtained using a novel application of the Split Hopkinson pressure bar. Similar mechanical properties were obtained for all pellets, apart from steam-exploded pellets, which were significantly higher. The quasi-static rigidity (Young’s modulus) was highest in the axial orientation and lowest in flexure. The dynamic mechanical strength and rigidity were highest in the diametral orientation. Pellet strength was found to be greater at high strain rates. The diametral Young’s Modulus was virtually identical at low and high strain rates for eucalyptus, mixed wood, sunflower, and microwave pellets, while the axial Young’s Modulus was lower at high strain rates. Correlations were derived between the milling energy in knife and ring roller mills for pellet durability, and quasi-static and dynamic pellet strength. Pellet durability and diametral quasistatic strain was correlated with HGI. In summary, pellet durability and mechanical tests at low and high strain rates can provide an indication of how a pellet will break down in a mill.

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Rey-De-Pedraza, V., D. A. Cendón, V. Sánchez-Gálvez, and F. Gálvez. "Measurement of fracture properties of concrete at high strain rates." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 375, no. 2085 (January 28, 2017): 20160174. http://dx.doi.org/10.1098/rsta.2016.0174.

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An analysis of the spalling technique of concrete bars using the modified Hopkinson bar was carried out. A new experimental configuration is proposed adding some variations to previous works. An increased length for concrete specimens was chosen and finite-element analysis was used for designing a conic projectile to obtain a suitable triangular impulse wave. The aim of this initial work is to establish an experimental framework which allows a simple and direct analysis of concrete subjected to high strain rates. The efforts and configuration of these primary tests, as well as the selected geometry and dimensions for the different elements, have been focused to achieve a simple way of identifying the fracture position and so the tensile strength of tested specimens. This dynamic tensile strength can be easily compared with previous values published in literature giving an idea of the accuracy of the method and technique proposed and the possibility to extend it in a near future to obtain other mechanical properties such as the fracture energy. The tests were instrumented with strain gauges, accelerometers and high-speed camera in order to validate the results by different ways. Results of the dynamic tensile strength of the tested concrete are presented. This article is part of the themed issue ‘Experimental testing and modelling of brittle materials at high strain rates’.

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Dexter, R. J., and K. S. Chan. "Viscoplastic Characterization of A533B Steel at High Strain Rates." Journal of Pressure Vessel Technology 112, no. 3 (August 1, 1990): 218–24. http://dx.doi.org/10.1115/1.2928617.

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The yield strength of A533 grade B class 1 steel is relatively low. Dynamic fracture in test specimens and pressure vessels made with this material is generally accompanied by significant plastic flow over a large range of strain rates. Therefore, it is imperative to use viscoplastic constitutive equations in the analysis of dynamic fracture in A533B steel. This paper describes the characterization and modeling of the viscoplastic behavior of A533B steel using the Bodner-Partom model. Tensile tests were performed from −60°C to 175°C at strain rates ranging from 10−3 to 103. The tensile data were used to obtain material constants in the Bodner-Partom constitutive equations over this range of temperatures. Comparison of calculated and measured stress-strain curves showed good agreement, validating the model and the procedures for determining the model constants. The use of the Bodner-Partom model for dynamic fracture modeling is then discussed.

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Peirs, Jan, Patricia Verleysen, Kim Verbeken, Frederik Coghe, and Joris Degrieck. "High Strain Rate Torsion and Bauschinger Tests on Ti6Al4V." Materials Science Forum 706-709 (January 2012): 774–79. http://dx.doi.org/10.4028/www.scientific.net/msf.706-709.774.

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An accurate isotropic and kinematic hardening model and description of the strain rate dependent material behaviour is necessary for simulation of fast forming processes. Consequently, the material model parameter identification requires experiments where large strains, high strain rates and strain path changes can be attained. Usually, quasi-static tension-compression Bauschinger tests are used to assess the materials kinematic hardening. Hereby it’s important to have the same specimen geometry and boundary conditions in the forward and reverse loading step which is not easily achieved in high strain rate testing techniques. In this work, high strain rate split Hopkinson bar torsion experiments on Ti6Al4V are carried out to study the constitutive material behaviour at large plastic strain and strain rate. In torsion experiments, due to the absence of cross sectional area reduction, higher strains than in tensile tests can be obtained. In addition, a modified torsional split Hopkinson bar setup is developed to perform dynamic Bauschinger tests. A shear reversed-shear load is applied instead of the classical tension-compression load cycle. The test results are analysed to find out if the technique can be used for characterisation of the kinematic material behaviour. Digital image correlation and finite element simulations are used to improve the interpretation of the experimental results.

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Piao, Ming Jun, Hoon Huh, Ik Jin Lee, Hyung Won Kim, and Lee Ju Park. "Validation of the Hardening Behaviors for Metallic Materials at High Strain Rate and Temperature by Using the Taylor Impact Test." Key Engineering Materials 715 (September 2016): 153–58. http://dx.doi.org/10.4028/www.scientific.net/kem.715.153.

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This paper is concerned with the validation of the dynamic hardening behaviors of metallic materials by comparing numerical and experimental results of the Taylor impact tests. Several uniaxial tensile tests are performed at different strain rates and temperatures by using three kinds of materials: 4130 steel (BCC); OFHC copper (FCC); and Ti6Al4V alloy (HCP). Uniaxial material tests are performed at a wide range of strain rates from 10−3 s−1 to 103 s−1. Moreover, tensile tests are performed at temperature of 25 °C and 200 °C at strain rates of 10−3 s−1, 10−1 s−1, and 102 s−1, respectively. A modified Johnson–Cook type thermal softening model is utilized for the accurate application of the thermal softening effect at different strain rates. The hardening behaviors of the three materials are characterized by comparing the seven sequentially deformed shapes of the projectile from numerical and experimental results of Taylor impact tests.

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Lee, Keunho, Yerim Lee, Sanghyun Woo, Changsoo Lee, and Leeju Park. "Experimental characterization of dynamic deformation behaviour for SCM440 steel at high strain rates." EPJ Web of Conferences 183 (2018): 02019. http://dx.doi.org/10.1051/epjconf/201818302019.

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The dynamic deformation behaviours of SCM 440 steel were characterized at the strain rates from 10-3 s-1 to 106 s-1. The uniaxial tensile tests at different temperature of 25 °C, 350 °C, and 700 °C were performed by a hydraulic universal testing machine equipped with a heating stage, and the compressive tests were conducted by using a spilt Hopkinson pressure bar (SHPB) at room temperature. Material coefficients of the Johnson-Cook constitutive model considering temperature effects were obtained based on the stressstrain relations from the experimental tests. In addition, Taylor impact tests on the SCM 440 steel were carried out to evaluate the accuracy of the determined material coefficients and characterize the dynamic behavior at the ultra-high strain rates and high temperature, by comparison with numerical simulations.

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Zou, Huiran, Weilong Yin, Chaocan Cai, Bing Wang, Ankang Liu, Zhen Yang, Yibin Li, and Xiaodong He. "The Out-of-Plane Compression Behavior of Cross-Ply AS4/PEEK Thermoplastic Composite Laminates at High Strain Rates." Materials 11, no. 11 (November 17, 2018): 2312. http://dx.doi.org/10.3390/ma11112312.

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The dynamic mechanical behavior of thermoplastic composites over a wide range of strain rates has become an important research topic for extreme environmental survivability in the fields of military protection, aircraft safety, and aerospace engineering. However, the dynamic compression response in the out-of-plane direction, which is one of the most important loading conditions resulting in the damage of composite materials, has not been investigated thoroughly when compared to in-plane compression and tensile behavior under high strain rates. Thus, we used split Hopkinson pressure bar (SHPB) tests to conduct the out-of-plane compression test of cross-ply carbon fiber-reinforced polyetheretherketone (AS4/PEEK) composite laminates. Afterward, the damage mechanism under different strain rates was characterized by the macrostructure morphologies and scanning electron microscope micrographs. Two major cases of the incomplete failure condition and complete failure condition were discussed. Dynamic stress-strain curves expound the strain rates dependencies of elastic modulus, failure strength, and failure strain. An obvious spring-back process could be observed under incomplete failure tests. For the complete failure tests, secondary loading could be observed by reconstructing and comparing the dynamic response history. Lastly, various failure modes that occurred in different loading strain rates illustrate that the damage mechanism also shows obvious strain rate sensitivity.

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Seidt, J. D., V.-T. Kuokkala, J. L. Smith, and A. Gilat. "Synchronous Full-Field Strain and Temperature Measurement in Tensile Tests at Low, Intermediate and High Strain Rates." Experimental Mechanics 57, no. 2 (November 1, 2016): 219–29. http://dx.doi.org/10.1007/s11340-016-0237-z.

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de Luca, A., F. di Caprio, E. Milella, G. Lamanna, M. Ignarra, and Francesco Caputo. "On the Tensile Behaviour of CF and CFRP Materials under High Strain Rates." Key Engineering Materials 754 (September 2017): 111–14. http://dx.doi.org/10.4028/www.scientific.net/kem.754.111.

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The paper deals with dynamic tensile tests on Carbon Fibre Reinforced Polymer – CFRP laminates. As a result of their viscoelastic nature, plastics exhibit rate dependence in their stress-strain response. The need to develop failure criteria to determine the dynamic failure stress for composite material under dynamic loading conditions is a current challenge for the research community. The main goal of such paper is to assess the efficiency of the analytical models provided by literature to predict the strain-rate effects on composite coupons tensile strength. Moreover, experimental tests have been performed in order to evaluate the mechanical behaviour of different stacking sequences at different strain rate.

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Liu, Chuan Xiong, Yu Long Li, Bing Hou, Wei Guo Guo, and Jin Long Zou. "Dynamic Compressive Behavior of Concrete at High Temperatures." Advanced Materials Research 217-218 (March 2011): 1811–16. http://dx.doi.org/10.4028/www.scientific.net/amr.217-218.1811.

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For investigating the effect of temperature on the dynamic properties of concrete material, tests for cylindrical concrete specimens at 23°C ~ 800°C were carried out by using Split Hopkinson Pressure Bar (SHPB) apparatus, and the strain rates ranged from 30/s to 220/s. Effects of temperature and strain-rate on the dynamic behavior of concrete were analyzed. The results show that: above 4000C, the dynamic compressive strength of concrete decreases with increasing temperature, and the enhancements of strain-rates on the compressive strength of concrete depend significantly on temperatures. Moreover, both strain-rate and temperature can enhance the peak strain of concrete.

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Chang, Xu Qing, and Tie Hua Ma. "Dynamic Testing at High Strain Rates of AZ31 Magnesium Alloys on SHPB Equipment." Applied Mechanics and Materials 303-306 (February 2013): 2648–51. http://dx.doi.org/10.4028/www.scientific.net/amm.303-306.2648.

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The mechanical behaviour of as-cast AZ31 Mg alloy has been investigated at strain rates up to 2.0×103s-1. Dynamic tests were carried out at room temperature using a Split Hopkinson Pressure Bar (SHPB) apparatus. Microstructural characteristic were analysed by Image MAT A1 optical microscopy. The results demonstrated that AZ31 Mg alloy exhibited obvious yield phenomena and strain hardening behaviour at high strain rates. The basically same curvature of stress-strain curves exhibited an similar strain hardening rate. The dynamic yield strength changes little and the peak stress increases with the strain rates. An examination by optical microscopy after high strain rate deformation reveals the occurrence of twinning and twin area percentage increases with the strain rate increasing.

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Dieffenbach, Tonja, Kai Treutler, and Volker Wesling. "High-speed tensile tests on high-manganese steel at low temperatures." Materials Testing 65, no. 1 (January 1, 2023): 124–33. http://dx.doi.org/10.1515/mt-2022-0245.

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Abstract Particularly in the automotive industry and the sector of liquid–gas storage, austenitic steels with a high energy absorption capacity are used. The light metals frequently used do not meet all requirements. Therefore, especially for components involved in crash situations, the cost-effective alternative with outstanding properties is used. In this respect, the high-manganese TWIP steels are of great interest, specifically due to their strength and ductility. Also in other research areas, the high-strength steels are moving into the focus of attention. For example, the properties of welded high-manganese steels at low temperature applications, such as those encountered during storage and transport of liquefied gases, are to be investigated. For this purpose, high-speed tensile tests are used to experimentally determine how the material behaves at different low temperatures and high strain rates. The investigations carried out provide results that can be used to draw conclusions about the strain rate and temperature dependence of the mechanical characteristics. These dependencies are shown as well.

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Xiong, L. X. "Uniaxial Dynamic Mechanical Properties Of Tunnel Lining Concrete Under Moderate-Low Strain Rate After High Temperature." Archives of Civil Engineering 61, no. 2 (June 1, 2015): 35–52. http://dx.doi.org/10.1515/ace-2015-0013.

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AbstractTo investigate the mechanical properties of tunnel lining concrete under different moderate-low strain rates after high temperatures, uniaxial compression tests in association with ultrasonic tests were performed. Test results show that the ultrasonic wave velocity and mass loss of concrete specimen begin to sharply drop after high temperatures of 600 °C and 400 °C, respectively, at the strain rates of 10-5s-1 to 10-2s-1. The compressive strength and elastic modulus of specimen increase with increasing strain rate after the same temperature, but it is difficult to obtain an evident change law of peak strain with increasing strain rate. The compressive strength of concrete specimen decreases first, and then increases, but decreases again in the temperatures ranging from room temperature to 800 °C at the strain rates of 10-5s-1 to 10-2s-1. It can be observed that the strain-rate sensitivity of compressive strength of specimen increases with increasing temperature. In addition, the peak strain also increases but the elastic modulus decreases substantially with increasing temperature under the same strain rate.

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Su, Caijun, James A. LaManna, Yanfei Gao, Warren C. Oliver, and George M. Pharr. "Plastic instability in amorphous selenium near its glass transition temperature." Journal of Materials Research 25, no. 6 (June 2010): 1015–19. http://dx.doi.org/10.1557/jmr.2010.0141.

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The deformation behavior of amorphous selenium near its glass transition temperature (31 °C) has been investigated by uniaxial compression and nanoindentation creep tests. Cylindrical specimens compressed at high temperatures and low strain rates deform stably into barrel-like shapes, while tests at low temperatures and high strain rates lead to fragmentation. These results agree well with stress exponent and kinetic activation parameters extracted from nanoindentation creep tests using a similarity analysis. The dependence of the deformation modes on temperature and strain rate can be understood as a consequence of material instability and strain localization in rate-dependent solids.

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Deshpande, V. M., and T. Chakraborty. "Dynamic compressive behaviour of Rewa shale through SHPB tests." IOP Conference Series: Earth and Environmental Science 1124, no. 1 (January 1, 2023): 012042. http://dx.doi.org/10.1088/1755-1315/1124/1/012042.

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Abstract The present work investigates the high strain rate behaviour of transversely isotropic Rewa shale using a split Hopkinson pressure bar. Rewa shale, a type of Vindhyan shale, is collected from Rewa district in the Madhya Pradesh state of India. Samples are loaded at various strain rates ranging from 110/s to 874/s. It is found that the compressive strength is rate-dependent, and it increases as the strain rate rises. The highest compressive strength is exhibited by samples at 0° and 90°. Samples at 30°, 45° and 60° fail at higher strains and strain rates. All samples subjected to dynamic compressive loading are pervasively fragmented. The results can potentially be applied to improve drilling and blasting operations.

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Best, T. M., J. H. McElhaney, W. E. Garrett, and B. S. Myers. "Axial Strain Measurements in Skeletal Muscle at Various Strain Rates." Journal of Biomechanical Engineering 117, no. 3 (August 1, 1995): 262–65. http://dx.doi.org/10.1115/1.2794179.

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A noncontact optical system using high speed image analysis to measure local tissue deformations and axial strains along skeletal muscle is described. The spatial resolution of the system was 20 pixels/cm and the accuracy was ±0.125mm. In order to minimize the error associated with discrete data used to characterize a continuous strain field, the displacement data were fitted with a third order polynomial and the fitted data differentiated to measure surface strains using a Lagrangian finite strain formulation. The distribution of axial strain along the muscle-tendon unit was nonuniform and rate dependent. Despite a variation in local strain distribution with strain rate, the maximum axial strain, Exx = 0.614 ± 0.045 mm/mm, was rate insensitive and occurred at the failure site for all tests. The frequency response of the video system (1000 Hz) and the measurement of a continuous strain field along the entire length of the structure improve upon previous noncontact optical systems for measurement of surface strains in soft tissues.

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Vilamosa, Vincent, Arild H. Clausen, Odd Sture Hopperstad, Tore Børvik, and Svein Skjervold. "Influence of Temperature and Strain Rate on the Mechanical Behaviour of Aluminium Alloy AA6060." Materials Science Forum 794-796 (June 2014): 520–25. http://dx.doi.org/10.4028/www.scientific.net/msf.794-796.520.

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In an attempt to improve the constitutive models for 6xxx aluminium alloys at high temperatures and high strain rates, a comprehensive test series has been carried out for AA6060. Uniaxial tension tests were performed at various strain rates from 0.01 s-1to 1000 s-1and temperatures from 20 °C to 350 °C. The tests were carried out using a standard tensile machine for low to moderate strain rates and a split-Hopkinson tension bar (SHTB) system for high strain rates. In both cases, an induction apparatus was used to heat the sample while local deformation measurements were obtained with a high-speed camera and used to estimate the true strain beyond necking. Strong coupling between the influence of strain rate and temperature on the stress-strain behaviour was found. At room temperature, the strain rate has a minor effect on the behaviour of AA6060. On the other hand, a significant increase of the yield stress and work-hardening with strain-rate is observed for temperatures above (K), being the melting temperature; i.e., above 673 K.

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Perez-Martin, M. J., J. K. Holmen, S. Thomesen, O. S. Hopperstad, and T. Børvik. "Dynamic Behaviour of a High-Strength Structural Steel at Low Temperatures." Journal of Dynamic Behavior of Materials 5, no. 3 (June 24, 2019): 241–50. http://dx.doi.org/10.1007/s40870-019-00206-x.

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Abstract The main objective of this experimental study is to determine the effect of low temperatures on the mechanical behaviour of Strenx 960 Plus high-strength structural steel at different strain rates and stress triaxialities. For this purpose, a comprehensive experimental campaign was designed to characterise the material at a wide range of temperatures and loading rates. The stress triaxiality was varied by testing specimens with different geometry. First, to determine the ductile-to-brittle transition temperature, instrumented Charpy V-notch impact tests were carried out at a range of temperatures from + 20 °C down to − 90 °C. The impact energy dropped gradually with decreasing temperature, but a clear transition temperature could not be identified. A fractography study exhibited a clear dimple structure, revealing predominantly ductile fracture at all temperatures. Then, uniaxial tension tests on smooth and pre-notched axisymmetric specimens under both quasi-static and dynamic loading rates were carried out at room temperature and low temperatures. These tests were conducted to characterise the rate-dependence of the stress–strain behaviour and the failure strain. The results revealed that under quasi-static conditions the flow stress increased with decreasing temperature, while the failure strain was nearly independent of the temperature. Dynamic tensile tests using the same specimen geometries were conducted in a split Hopkinson tension bar at + 20 °C and − 40 °C. The material exhibited a positive strain rate sensitivity at all investigated temperatures. This experimental study reveals that the Strenx 960 Plus steel retains its ductility at temperatures as low as − 40 °C. Brittle failure could not be observed even with combined high strain rate, high stress triaxiality and low temperature.

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Balandin, V. V., L. V. Meyer, and S. Abdel-Malek. "DYNAMIC TESTS OF FROZEN SAND SOILS." Problems of strenght and plasticity 81, no. 4 (2019): 443–48. http://dx.doi.org/10.32326/1814-9146-2019-81-4-443-448.

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The study of the laws of contact interaction of hard and deformable impactors with frozen soils is of great scientific and applied value. In solving such problems, numerical methods are widely used. For numerically modeling the behavior of frozen soil under dynamic loading, it is necessary to use models of soil media that adequately describe their behavior at various negative temperatures, humidities and strain rates. To identify the parameters of these models, experimental studies are required for determining dynamic properties of soils at low temperatures. The paper presents the results of experimental studies of dynamic deformation of samples of frozen sand with humidities of 10% and 18%. Compression experiments were conducted using a stand implementing the Kolsky method. Deformation curves of frozen sand at a temperature of -18 °С were obtained under uniaxial stress conditions at various strain rates in the range of 400-2500 s-1. Diagrams of strength of frozen sand under uniaxial compression as a function of strain rate are constructed. The diagrams are linear for samples of different humidity in the studied range of strain rates. Maximum stresses in frozen water-saturated sand are higher than those in frozen sand of 10% humidity. With increasing strain rate, compressive strength of water-saturated sand grows faster than that of sand with a moisture content of 10%: at a strain rate of about 500 s-1, the stresses in frozen water-saturated sand, at which the samples fail, are 1.5 times higher than those in the frozen sand with a moisture content of 10%, and at a strain rate of 2500 s-1 they are 3 times as high.

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Bouda, Pascal, Bertrand Langrand, Delphine Notta-Cuvier, Eric Markiewicz, and Fabrice Pierron. "A computational approach to design new tests for viscoplasticity characterization at high strain-rates." Computational Mechanics 64, no. 6 (June 26, 2019): 1639–54. http://dx.doi.org/10.1007/s00466-019-01742-y.

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Shioiri, J., K. Sakino, and T. Santoh. "Two strain rate change tests for derivation of constitutive relationship of metals at very high rates of strain." Le Journal de Physique IV 04, no. C8 (September 1994): C8–489—C8–494. http://dx.doi.org/10.1051/jp4:1994876.

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Temimi, N., and Noelle Billon. "Experimental Studies of the Behaviour at High Strain Rates of Unfilled and Filled Polypropylenes." Applied Mechanics and Materials 3-4 (August 2006): 363–68. http://dx.doi.org/10.4028/www.scientific.net/amm.3-4.363.

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Thermo mechanical behaviour of unfilled and filled polypropylenes are studied in tension from 10-4 to 102 s-1. Complementary low velocity compression and shear tests are also performed. A high-speed video camera (up to 2500 frames/s) combined with image analysis, image correlation and an infra red pyrometer allow measuring 3D-strain fields and temperature during tests. Thus, data can be processed without restrictive assumptions. Beside usual (for polymers) temperature and strain rate sensitivities it is found that plastic deformation in these materials does not obey incompressibility assumption. Voiding damage is evidenced in the polymer matrix by SEM observations that result in volume change and significant decrease in Young modulus for both materials. Moreover, an increase in the temperature of more than 10 °C is observed and is likely to modify the behaviour of each material at high strain rates. Shear and compression measurements demonstrate that yield criteria and constitutive equation depend on loading. It is concluded that apparent yield stress in semi-crystalline polypropylene can be a result of a combination of “non strain rate sensitive” “non-cohesive mechanisms” and “strain rate sensitive” “cohesive mechanisms”. Experimental characterisation on polymers should then be revisited as most of the usual assumptions are invalid and non monotonic tests should be generalized.

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Qin, Jin Gui, Fang Yun Lu, Yu Liang Lin, Xue Jun Wen, and Ming Zu Liang. "Dynamic Tensile Behaviour and Full Field Strain Measurement of High Strength Steel." Applied Mechanics and Materials 275-277 (January 2013): 1859–65. http://dx.doi.org/10.4028/www.scientific.net/amm.275-277.1859.

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Uniaxial tensile tests were conducted on high strength steel 600 (HS600) in Split-Hopkinson Tension Bar at different strain rates in the range of 1100 to 3200s-1and in electromechanical universal testing machine at the strain rate of 1.1×10-3s-1. Digital image correlation was used together with high-speed photography to obtain full-field displacement and strain in the tensile specimens at dynamic strain rate tests. This high strength steel shows significant strain rate sensitivity. Based on the experimental results, the material parameters of Johnson-Cook model are determined. This model fits the experimental data well in the plastic zone.

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Adlafi, Morwan, Bertrand Galpin, Laurent Mahéo, Christian C. Roth, Dirk Mohr, and Vincent Grolleau. "Plane strain tension fracture at high strain rate." EPJ Web of Conferences 250 (2021): 01020. http://dx.doi.org/10.1051/epjconf/202125001020.

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Under plane stress conditions, most micromechanical and phenomenological models predict a minimum in ductility for plane strain tension stress state. Therefore, the stress state of plane strain tension plays a crucial role in many forming and crash applications and the reliable measurement of the strain to fracture for plane strain tension is particularly crucial when calibrating modern fracture initiation models. Recently, a new experimental technique has been proposed for measuring the strain to fracture for sheet metal after proportional loading under plane strain conditions. The basic configuration of the new setup includes a dihedral punch which applies out-of-plane loading onto a Nakazima-type of discshaped specimen with two symmetric holes and an outer diameter of 60 mm. In the present work, the applicability of the test is extended to high strain rates. High strain rates of about 100/s to 200/s are obtained using a drop weight tower device with an original sensor for load measurements. Quasi static tests are also performed for comparison, keeping the same specimen geometry, image recording parameters and set-up. The effective strains at fracture are compared from quasi-static to high strain rate loading for three different materials, i.e one aluminium alloy and two steels.

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Naumov, Anton, Anatolii Borisov, and Anastasiya Y. Doroshchenkova. "Numerical Simulation of Hot High Strain Rate Torsion Tests for Al-Based Alloys." Key Engineering Materials 822 (September 2019): 66–71. http://dx.doi.org/10.4028/www.scientific.net/kem.822.66.

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The present research describes the comparison of numerical and physical simulation of hot high strain rate torsion tests for Al-based alloys in order to clarify the accuracy of calculations using basic grades of materials in Deform-3DTM software. A comparative visual analysis of the results is presented. Obtained data on the distribution of temperatures, strains, stresses and strain rates during the torsion test are discussed.

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Shi, Bin Bin, Ying Sun, Li Chen, and Jia Lu Li. "Energy Absorption of Ultra-High Molecular Weight Polyethylene Fiber-Reinforced Laminates at High Strain Rates." Applied Mechanics and Materials 34-35 (October 2010): 1532–35. http://dx.doi.org/10.4028/www.scientific.net/amm.34-35.1532.

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Some dynamic compressive tests about Ultra-High Molecular Weight Polyethylene Fiber-reinforced laminated Composites have been done using SHPB experimental system．The stress-strain curves of UHMWPE Fiber-reinforced Composites of three different laminated angles (0/90°, 0/90/45/-45°, 0/90/30/-60/60/-30°) are obtained at higher strain rates and their dynamic mechanical properties are also investigated at the same time．Based on all the stress-strain curves obtained, the characteristics of energy absorption of UHMWPE fiber angle-plied composites are analyzed and discussed．It is found that laminated angle has made little effect on the dynamic energy absorption of composites at higher strain rates．In addition，delamination and compaction in the thickness direction constitute the main dynamic failure mechanisms, which are studied by means of image analyses for the specimens after compression.

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Amaro, Ana M., Maria A. Neto, José S. Cirne, and Paulo N. B. Reis. "Mechanical Characterization of Different Aluminium Foams at High Strain Rates." Materials 12, no. 9 (May 1, 2019): 1428. http://dx.doi.org/10.3390/ma12091428.

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Samples having nominal compositions of AlSi12 and Al6082-T4 were prepared using a lost wax casting process, with nominal relative densities of 20%, 40%, and 60%, as well as arrangements of a uniform cell structure (US) or a dual-size cell (DS). For comparison, samples of aluminium foam-filled tubes having the same nominal composition were also prepared with the same technique, with nominal relative densities of 20% and similar arrangements (US and DS). Impact tests at different velocities were performed using a split Hopkinson pressure bar (SHPB). It is possible to conclude that Al6082-T4 foams have better performance, in both configurations, than the AlSi12 ones. Considering a uniform cell structure and a density of 20%, the absorbed energy by the Al6082-T4 foams was around 25% higher than the value observed for the AlSi12 ones. In terms of arrangement, the US structure presents absorbed energy around 57% lower than the DS ones, while the AlSi12 foams with a relative density of 20% were compared. Finally, the absorbed energy growths from 2.8 × 105 to 5.2 × 105 J/m3, when the density increased from 20% to 60%. However, when these foams were involved with a tube, the performances increased substantially.

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Lou, Yan, Luo Xing Li, and Na Luan. "Flow Stress Correction of AZ80 Magnesium Alloy for Deformation Heating at High Strain Rates during Hot Compression." Advanced Materials Research 129-131 (August 2010): 1326–30. http://dx.doi.org/10.4028/www.scientific.net/amr.129-131.1326.

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Accurate description of the material flow stress behaviour is an essential requirement for FEM simulation of metal forming processes. In the present hot compression tests of AZ80 magnesium alloy were performed on Gleeble 3500 at strain rates between 0.01-50s-1 and deformation temperatures between 300-450°C to determine the flow stress data of the AZ80 magnesium alloy. It was noticed that with increasing strain rate, deformation heating become more pronounced since there is no time for heat escaping during hot compression tests. Thus, a flow stress correction for deformation heating at high strain rates was carried out for the calculation of the constants of constitutive equation. Validation tests were then performed. Good agreements between the predicted and measured values in extrusion pressure were achieved.

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Rouf, Khizar, Aaditya Suratkar, Jose Imbert-Boyd, Jeffrey Wood, Michael Worswick, and John Montesano. "Effect of Strain Rate on the Transverse Tension and Compression Behavior of a Unidirectional Non-Crimp Fabric Carbon Fiber/Snap-Cure Epoxy Composite." Materials 14, no. 23 (November 29, 2021): 7314. http://dx.doi.org/10.3390/ma14237314.

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The strain rate-dependent behavior of a unidirectional non-crimp fabric (UD-NCF) carbon fiber/snap-cure epoxy composite loaded along the transverse direction under quasi-static and dynamic conditions was characterized. Transverse tension and compression tests at quasi-static and intermediate strain rates were performed using hydraulic testing machines, while a split Hopkinson pressure bar (SHPB) apparatus was used for transverse compression tests at high strain rates. A pulse shaper was used on the SHPB apparatus to ensure dynamic equilibrium was achieved and that the test specimens deformed homogenously with a nearly constant strain rate. The transverse tensile strength at a strain rate of 16 s−1 increased by 16% when compared to that at quasi-static strain rates, while distinct localized fracture surface morphology was observed for specimens tested at different strain rates. The transverse compressive yield stress and strength at a strain rate of 325 s−1 increased by 94% and 96%, respectively, when compared to those at quasi-static strain rates. The initial fracture plane orientation for the transverse compression tests was captured with high-speed cameras and found to increase with increasing strain rate. The study provides an important data set for the strain rate-dependent response of a UD-NCF composite material, while the qualitative fracture surface observations provide a deeper understanding of the failure characteristics.

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Worswick, Michael J., R. Smerd, C. P. Salisbury, S. Winkler, and David J. Lloyd. "High Strain Rate Behaviour of Aluminium Alloy Sheet." Materials Science Forum 519-521 (July 2006): 139–46. http://dx.doi.org/10.4028/www.scientific.net/msf.519-521.139.

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This paper presents results from quasi-static and high rate tensile testing of three aluminum sheet alloys, AA5754, AA5182 and AA6111, all of which are candidates for replacing mild steel in automotive bodies. Tests were performed at quasi-static rates using an Instron apparatus and at strain rates of 600 to 1500 s-1 using a tensile split Hopkinson bar. Additionally, an in-depth investigation was performed to determine the levels of damage within the materials and its sensitivity to strain rate. The constitutive response of all of the aluminum alloys tested showed only mild strain rate sensitivity. Dramatic increases in the elongation to failure were observed with increases in strain rate as well as greater reduction in area. Additionally, the level of damage was seen to increase with strain rate.

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Zhao, Peng Duo, Yu Wang, Jian Ye Du, Lei Zhang, Zhi Peng Du, and Fang Yun Lu. "Using Split Hopkinson Pressure Bars to Perform Large Strain Compression Tests on Neoprene at Intermediate and High Strain Rates." Advanced Materials Research 631-632 (January 2013): 458–62. http://dx.doi.org/10.4028/www.scientific.net/amr.631-632.458.

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The strain rate sensitivity of neoprene is characterized using a modified split Hopkinson pressure bar (SHPB) system at intermediate (50 s-1, 100 s-1) and high (500 s-1, 1000 s-1) strain rates. We used two quartz piezoelectric force transducers that were sandwiched between the specimen and experimental bars respectively to directly measure the weak wave signals. A laser gap gage was employed to monitor the deformation of the sample directly. Three kinds of neoprene rubbers (Shore hardness: SHA60, SHA65, and SHA70) were tested using the modified split Hopkinson pressure bar. Experimental results show that the modified apparatus is effective and reliable for determining the compressive stress-strain responses of neoprene at intermediate and high strain rates.

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Vercruysse, Florian, Felipe M. Castro Cerda, Roumen Petrov, and Patricia Verleysen. "Static and dynamic response of ultra-fast annealed advanced high strength steels." EPJ Web of Conferences 183 (2018): 03017. http://dx.doi.org/10.1051/epjconf/201818303017.

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Ultra-fast annealing (UFA) is a viable alternative for processing of 3rd generation advanced high strength steels (AHSS). Use of heating rates up to 1000°C/s shows a significant grain refinement effect in low carbon steel (0.1 wt.%), and creates multiphase structures containing ferrite, martensite, bainite and retained austenite. This mixture of structural constituents is attributed to carbon gradients in the steel due to limited diffusional time during UFA treatment. Quasi-static (strain rate of 0.0033s-1) and dynamic (stain rate 600s-1) tensile tests showed that tensile strength of both conventional and UFA sample increases at high strain rates, whereas the elongation at fracture decreases. The ultrafast heated samples are less sensitive to deterioration of elongation at high strain rates then the conventionally heat treated ones. Based on metallographic studies was concluded that the presence of up to 5% of retained austenite together with a lower carbon martensite/bainite fraction are the main reason for the improved tensile properties. An extended stability of retained austenite towards higher strain values was observed in the high strain rate tests which is attributed to adiabatic heating. The extension of the transformation induced plasticity (TRIP) effect towards higher strain values allowed the UFA-samples to better preserve their deformation capacity resulting in expected better crashworthiness.

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Pun, Lalit, Guilherme Corrêa Soares, Suprit Bhusare, Matti Isakov, and Mikko Hokka. "Microscale Strain Localizations and Strain-Induced Martensitic Phase Transformation in Austenitic Steel 301LN at Different Strain Rates." Metals 13, no. 2 (January 20, 2023): 207. http://dx.doi.org/10.3390/met13020207.

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Microscopic strain and strain-induced phase transformation during plastic deformation in metastable austenitic steel were investigated at different strain rates. Quasi in-situ tension tests were performed sequentially with well-defined elongation intervals at room temperature at strain rates of 10−3 s−1 and 10−1 s−1. The tests were monitored by high-resolution optical imaging with a microscopic lens at a resolution of 0.23 µm/pixel. The macroscopic temperature was also measured with an infrared (IR) camera. The microstructure-level strain localizations were observed on the surface of the etched specimens by means of microscale digital image correlation (µDIC). Additionally, the microstructure was characterized by electron backscatter diffraction (EBSD) at the same location before and after deformation. The results of the study indicated that microscopic strain localizations favored the formation of α′-martensite particles. At the lower strain rate, high local strain concentrations formed at several locations in the microstructure, correlating with the areas where the formation of large martensite islands occurred. Martensite particles of various sizes formed nearby each other at the lower strain rate, whereas at the higher strain rate, martensite islands remained small and isolated. Although the macroscopic increase in temperature at both the studied strain rates was very low, at the higher strain rate, local heating on the microscopic scale could take place at the newly nucleated martensite embryos. This inhibited the further growth of the martensite particles, and local strain distribution also remained more homogeneous than at the lower strain rate.

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Zhang, Bin, Jin Wang, Yang Wang, Yu Wang, and Ziran Li. "Strain-Rate-Dependent Tensile Response of Ti–5Al–2.5Sn Alloy." Materials 12, no. 4 (February 22, 2019): 659. http://dx.doi.org/10.3390/ma12040659.

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This study is an experimental investigation on the tensile responses of Ti–5Al–2.5Sn alloy over a wide range of strain rates. Uniaxial tension tests within the rate range of 10−3–101 s−1 are performed using a hydraulic driven MTS810 machine and a moderate strain-rate testing system. The high-rate uniaxial tension and tension recovery tests are conducted using a split-Hopkinson tension bar to obtain the adiabatic and isothermal stress–strain responses of the alloy under dynamic loading conditions. The experimental results show that the value of the initial yield stress increases with the increasing strain rate, while the strain rate sensitivity is greater at high strain rates. The isothermal strain-hardening behavior changes little with the strain rate, and the adiabatic temperature rise is the main reason for the reduction of the strain-hardening rate during high strain-rate tension. The electron backscatter diffraction (EBSD) analysis of the post-deformed samples indicates that there are deformation twins under quasi-static and high-rate tensile loadings. Scanning electron microscope (SEM) micrographs of the fracture surfaces of the post-deformed samples show dimple-like features. The Zerilli–Armstrong model is modified to incorporate the thermal-softening effect of the adiabatic temperature rise at high strain rates and describe the tension responses of Ti–5Al–2.5Sn alloy over strain rates from quasi-static to 1050 s−1.

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Shen, Jian Hu, Mike Xie, Xiao Dong Huang, Shi Wei Zhou, and Dong Ruan. "Compressive Behavior of Luffa Sponge Material at High Strain Rate." Key Engineering Materials 535-536 (January 2013): 465–68. http://dx.doi.org/10.4028/www.scientific.net/kem.535-536.465.

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The strain rate effect of luffa sponge material is an indispensable property for it to be used for acoustic, vibration, and impact energy absorption. Compressive tests at different strain rates on cylindrical column specimens of luffa sponge material were conducted over a wide density ranging from 24 to 64 kg/m3. A photographic technique was applied to measure the section area of the specimen with irregular shape. The mechanical properties of luffa sponge material at various strain rates were obtained based on this measurement. The dynamic data were compared to those of quasi-static experiments. It was found that compressive strength, plateau stress and specific energy absorption of luffa sponge material were sensitive to the rate of loading. Empirical formulae were developed for strength, densification strain and specific energy absorption at various strain rates in the macroscopic level by considering the luffa fiber as base material.

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Zheng, Lianqiong, Yilong Ye, Jinping zhuang, and Yongqian Zheng. "Impact Tensile Behaviors of PVDF Building Coated Fabrics." Advances in Civil Engineering 2020 (October 29, 2020): 1–10. http://dx.doi.org/10.1155/2020/1620760.

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The paper presents the impact tensile behaviors of two common building membranes (Ferrari 1002T2 membrane and XYD 300N membrane) in PVDF-coated-fabric membrane structures. The tests are conducted using the split Hopkinson bar test device. Typical forms of stress and strain are applied for comparing the stress-strain relationship between quasi-static and high strain rates. Besides, the failure mechanism and energy absorption at high strain rates are discussed. The results show that with the increase of strain rates, the growth rate of the stress of PVDF membrane decreases gradually, which is different from the stress-strain relationship in low strain rates. At high strain rates, the ultimate tensile strength increases linearly with the increase of strain rates. In addition, the energy absorption capacity of the material increases with the increase of strain rates. The results can provide an important basis for the design and analysis of membrane structures under the impact loads.

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Chen, Wei, Yanfei Gu, Yingping Guan, and Chunfa Dong. "Dynamic recrystallisation and modelling of microstructural evolution of high-titanium-content 6061 aluminium alloy." International Journal of Materials Research 111, no. 4 (May 1, 2020): 316–24. http://dx.doi.org/10.1515/ijmr-2020-1110407.

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Abstract The dynamic recrystallisation behaviour of high-titaniumcontent 6061 aluminium alloy was investigated by hot compression tests within the temperature range of 623- 783 K and at strain rates of 0.01 -10 s-1. The characteristics of the true stress-strain curves acquired in the hot compression tests were investigated, and it was observed that the dynamic recrystallisation of high-titanium-content 6061 aluminium alloy occurs within the range of deformation temperatures of 623 -783 K, with strain rates of 0.001 - 0.1 s-1as evinced by a physically-based constitutive analysis. The kinetic model of dynamic recrystallisation was deduced to describe the dynamic recrystallisation behaviour of high-titanium-content 6061 aluminium alloy, and the dynamic recrystallisation grain size model was also constructed.

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SAKINO, KIYOTAKA. "STRAIN RATE DEPENDENCE OF DYNAMIC FLOW STRESS OF 2017 ALUMINUM ALLOY AT VERY HIGH STRAIN RATES." International Journal of Modern Physics B 22, no. 09n11 (April 30, 2008): 1209–14. http://dx.doi.org/10.1142/s0217979208046554.

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To estimate the strain rate dependence of the dynamic flow stress of aluminum alloys, 2017-O and - T4, high strain rate and rate reduction tests are performed at strain rates ranging from about 1000/sec to 30000/sec. A steep increase in the flow stress is observed for 2017-O at the strain rate of about 3000/sec. For 2017-T4, the above phenomenon is observed at the strain rate above about 10000/sec. A simplified model for dislocation kinetics under dynamic plastic deformation is employed which can represent a transition in the rate controlling mechanism of dislocation motion from a thermally activated process to a viscous drag. It is expected that the steep increase in the flow stress observed at high strain rates is attributed to the rate dependence of the viscous drag on the dislocation motion.

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Gomon, Dmitri, Mikko Hokka, and Veli Tapani Kuokkala. "Dynamic Compression Behavior and Numerical Modeling of Ti-6246 Alloy at Different Temperatures." Key Engineering Materials 527 (November 2012): 159–64. http://dx.doi.org/10.4028/www.scientific.net/kem.527.159.

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The current research concentrates on the characterization of the mechanical behavior of Ti-6Al-2Sn-4Zr-6Mo alloy. The material was studied in compression using the Split Hopkinson Pressure Bar (SHPB) equipment at high strain rates and conventional servohydraulic materials testing devices at low strain rates. The tests were performed at temperatures ranging from room temperature up to 600 °C. According to the results of the compression tests, the strain hardening rate of the studied material decreases strongly with increasing strain rate. The observed strong decrease in the strain hardening rate with increasing strain rate is a consequence of the extremely strong adiabatic heating of the material due to its high strength and low thermal conductivity. In this study, the Johnson-Cook material model parameters were obtained from isothermal stress-strain curves that were calculated from the experimental (adiabatic) stress-strain data. In this paper, the results of the mechanical testing at high strain rates and the numerical modeling of the material behavior are presented and discussed in details.

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Guo, Lingmei, and Yang Wang. "HIGH-RATE TENSILE BEHAVIOR OF SILICONE RUBBER AT VARIOUS TEMPERATURES." Rubber Chemistry and Technology 93, no. 1 (January 1, 2020): 183–94. http://dx.doi.org/10.5254/rct.19.81562.

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ABSTRACT The effects of strain rate and temperature on the tensile behavior of silicone rubber were investigated. The quasi-static uniaxial tensile experiments were conducted using an electromechanical testing system, and the high-rate uniaxial tensile tests were performed employing a modified split Hopkinson tension bar technique for low-strength and low-impedance materials. The tensile responses were obtained at strain rates of 0.001–1400 s−1 and temperatures ranging from −50 to 50 °C. The experiments reveal that the tensile stress–strain behavior of silicone rubber is nonlinear and highly dependent on strain rate and temperature. The values of stiffness and nominal stress at a given elongation increase with increased strain rate and decrease with increasing temperature. It is appropriate to postulate that the tensile response at high strain rates arises from the combination of hyperelasticity and viscoelasticity. According to the incompressibility assumption, a phenomenologically inspired visco-hyperelastic model was proposed to describe the constitutive behavior of silicone rubber over wide ranges of strain rates and temperatures.

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Journal articles on the topic 'High strain-rates tests'

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