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Статті в журналах з теми "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.
Повний текст джерелаАнотація:
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.
Повний текст джерела
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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.
Повний текст джерелаАнотація:
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.
Повний текст джерелаАнотація:
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.
Повний текст джерелаАнотація:
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.
Повний текст джерелаАнотація:
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.
Повний текст джерелаАнотація:
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.
Повний текст джерелаАнотація:
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.
Повний текст джерелаАнотація:
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.
Повний текст джерелаАнотація:
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.
Дисертації з теми "High strain-rates tests"
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Walker, A. G. "Mechanical behaviour of copper at high strain rates." Thesis, Loughborough University, 1987. https://dspace.lboro.ac.uk/2134/10949.
Повний текст джерелаАнотація:
The primary objectives of this research were to determine the macroscopic properties of polycrystalline OFHC copper for various grain sizes over a wide range of strain rates and temperatures, and to relate the properties to the fundamental microscopic mechanisms which control the deformation characteristics of the material....
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Shen, Yubin. "The chemical and mechanical behaviors of polymer / reactive metal systems under high strain rates." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45804.
Повний текст джерелаАнотація:
As one category of energetic materials, impact-initiated reactive materials are able to release a high amount of stored chemical energy under high strain rate impact loading, and are used extensively in civil and military applications. In general, polymers are introduced as binder materials to trap the reactive metal powders inside, and also act as an oxidizing agent for the metal ingredient. Since critical attention has been paid on the metal / metal reaction, only a few types of polymer / reactive metal interactions have been studied in the literature. With the higher requirement of materials resistant to different thermal and mechanical environments, the understanding and characterization of polymer / reactive metal interactions are in great demand. In this study, PTFE (Polytetrafluoroethylene) 7A / Ti (Titanium) composites were studied under high strain rates by utilizing the Taylor impact and SHPB tests. Taylor impact tests with different impact velocities, sample dimensions and sample configurations were conducted on the composite, equipped with a high-speed camera for tracking transient images during the sudden process. SHPB and Instron tests were carried out to obtain the stress vs. strain curves of the composite under a wide range of strain rates, the result of which were also utilized for fitting the constitutive relations of the composite based on the modified Johnson-Cook strength model. Thermal analyses by DTA tests under different flow rates accompanied with XRD identification were conducted to study the reaction mechanism between PTFE 7A and Ti when only heat was provided. Numerical simulations on Taylor impact tests and microstructural deformations were also performed to validate the constitutive model built for the composite system, and to investigate the possible reaction mechanism between two components. The results obtained from the high strain rate tests, thermal analyses and numerical simulations were combined to provide a systematic study on the reaction mechanism between PTFE and Ti in the composite systems, which will be instructive for future energetic studies on other polymer / reactive metal systems.
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Ruiz, Daniel John. "Mechanical behaviour of materials at high rates of strain : a study of the double notch shear test." Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280611.
Повний текст джерела
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Todesco, Sérgio Roberto. "Projeto e construção de um dispositivo para ensaio de impacto em materiais, barra de compressão." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-13032018-103518/.
Повний текст джерелаАнотація:
Esta dissertação apresenta um projeto de um dispositivo para levantar dados característicos de materiais submetidos às altas taxas de deformação, dispositivo este que leva o nome do seu idealizador o engenheiro Inglês Sir Bertram Hopkinson. Mais especificamente, esta dissertação está inseparavelmente ligada ao desenvolvimento de um embalado para transporte de elementos radioativos como sendo uma das partes do escopo geral, de um projeto da CAPES em convênio com o Centro de Ciência e Tecnologia de Materiais - CCTM do, Instituto de Pesquisas Energéticas e Nucleares IPEN - CNEN/SP, autarquia associada à Universidade de São Paulo. O desenvolvimento do dispositivo faz parte do escopo de obtenção, e levantamento dos dados necessários para o projeto, e a construção do embalado. Esta dissertação versa sobre a concepção mecânica do dispositivo, importante, dividida em duas partes, dimensionamento das barras, que seriam a barra de impacto, a barra de entrada, e a barra de saída, e o dimensionamento do dispositivo de impacto. O dimensionamento das barras envolve conhecimentos do conceito de ondas elásticas em meios sólidos para que o comprimento das barras seja estimado de forma a servir de guia das ondas elásticas, que provocarão a deformação no corpo de prova, e possibilite a boa leitura dessas ondas para análise dos dados. O dispositivo de impacto, este tem que ser robusto o suficiente para produzir a onda de tensão que deforme o corpo de prova, mas não para deformar plasticamente as barras, que terão que continuar durante todo o teste dentro do regime elástico.This dissertation presents a design of a device to collect characteristic data of materials submitted to the high strain rates, device that takes the name of its idealizer the English engineer Sir Bertram Hopkinson. More specifically, this dissertation is inseparably linked to the development of a package for the transport of radioactive elements as part of the general scope of a CAPES project in partnership with the Materials Science and Technology Center (CCTM), Nuclear and Energy Research Institute IPEN - CNEN / SP, autarchy associated with the University of São Paulo. The development of the device is part of the scope of procurement, and collection of data required for the design, and the construction of the packaging. This dissertation deals with the mechanical design of the device, important, divided into two parts, dimensioning of the bars, which would be the impact bar, the input and output bars and the design of the impact device. The sizing of the bars involves knowledge of the concept of elastic waves in solid media so that the length of the bars is estimated in order to serve as a guide for the elastic waves, which will cause deformation in the test body, and enable a good reading of these waves for analysis of the data. The impact device has to be robust enough to produce the stress wave that deforms the test body but not to deform the bars plastically, which will have to continue throughout the test within the elastic regime.
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Lee, Chih-Chun, and 李季春. "A Study on Material Tests in High Strain Rates." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/32824664376501112901.
Повний текст джерелаАнотація:
碩士國立臺灣大學
機械工程學研究所
97
The finite element method has been widely applied to simulate the crashworthiness tests in the automotive industry. However, in the high strain-rate deformation, the yield strength and ultimate tensile strength of a material may be changed. In order to obtain accurate results, the stress-strain relations of the material in high strain rates are required for the simulations of the crashworthiness tests. There are various high strain-rate tests available to obtain the stress-strain relations, such as the split Hopkinson bar system, direct impact method, and servo hydraulic system. Each test method is applicable in certain strain-rate range. In the present study, the servo hydraulic system MTS819 was adopted to implement the high rate tests in a strain-rate range below 500s-1. The testing equipment including the machine frame, load cell, and data acquisition system was fine tuned first to make it suitable for the tests. As strain rate increasing, the amplitude of the stress vibration acquired from load cell increases. Hence, the efforts to determine the cause of the stress vibration and the remedy approaches were made. The actual strain rate measured in specimen during the test was considered. It was found that there is an acceleration zone in the beginning of the test. So it is important to determine when the strain rate comes to a constant strain rate. The stress-strain curves acquired from the experiments conducted in the present study were fitted by the Cowper-Symonds equation and then input to the finite element software for simulations. Through the finite element simulations, the actual strain rates in specimen and stress distributions in the grip during experiment were investigated. The finite element simulations were also performed to examine the strain rate effect on the impact of a hydro-formed engine cradle to a rigid wall. The experimental approach and the finite element simulations results obtained in the present study could be valuable references for the future researches in field of deformation on the high strain rates.
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Pires, Tiago Leonel Marques Carmona Afonso. "Barra de Pressão de Hopkinson." Master's thesis, 2016. http://hdl.handle.net/10400.26/15072.
Повний текст джерелаАнотація:
Nos dias de hoje, para a realização de qualquer projeto, é necessário fazer uma rigorosa
escolha dos materiais que são utilizados, e para tal é preciso saber como é que estes se
comportam perante os vários fatores presentes. Muitas das vezes estes comportamentos são
estudados através de ensaios destrutivos com taxas de deformação elevadas, tal como é o caso
do sistema de uma Barra de Pressão de Hopkinson.
Este trabalho tem como objetivo a criação de um projeto de uma Barra de Pressão de
Hopkinson para ser construída no laboratório do Departamento de Ciências e Tecnologia da
Escola Naval, para que no futuro os Cadetes da Classe de Engenharia Naval do Ramo Mecânica
possam realizar ensaios, e estudar os comportamentos dos materiais perante taxas de
deformação elevadas.
Nesta Dissertação está explicada toda a teoria que está por trás do sistema de uma Barra
de Pressão de Hopkinson, e todos os passos que foram tomados para a criação do projeto, para
simplificar da melhor forma possível toda a física que está por trás deste sistema, com o intuito
de facilitar a leitura.Nowadays, for the realization of any project it’s necessary to make an accurate choice of the materials that are going to be used, and for that you need to know how they behave before the various factors present. These behaviors are usually studied in destructive tests at high strain rate, such as the system of the Split Hopkinson Pressure Bar. This works aims to create a design of a Split Hopkinson Pressure Bar to be built in the laboratory of the Department of Science and Technology of the Portuguese Naval Academy, so that the future Cadets of the Naval Engineering Class of the Mechanical Branch can perform tests and study the behavior of the material in high strain rates. In this Dissertation is explained the whole theory behind the system of a Split Hopkinson Pressure Bar and all the steps that were taken to the creation of design, in order to simplify the best possible way, all physics that is behind this system, in order to facilitate the reading
Частини книг з теми "High strain-rates tests"
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Kwon, J. B., H. Huh, and C. N. Ahn. "An Improved Technique for Reducing the Load Ringing Phenomenon in Tensile Tests at High Strain Rates." In Dynamic Behavior of Materials, Volume 1, 253–57. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-22452-7_35.
Повний текст джерела
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Wolff, C., and A. R. Bunsell. "Testing of Composites at High Strain Rates Using ± 45° Shear Test." In Developments in the Science and Technology of Composite Materials, 653–58. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-0787-4_90.
Повний текст джерела
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El-Magd, E., and M. Abouridouane. "Compression Test on Magnesium Alloy MgAl8Zn at High Strain Rates and Temperatures." In Magnesium Alloys and their Applications, 324–29. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2006. http://dx.doi.org/10.1002/3527607552.ch51.
Повний текст джерела
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Fletcher, Lloyd, and Fabrice Pierron. "A Simple Data-Rich IBII Test for Identifying All Orthotropic Stiffness Components at High Strain Rates." In Dynamic Behavior of Materials, Volume 1, 53–56. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-86562-7_9.
Повний текст джерела
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Lok, T. S., X. B. Li, P. J. Zhao, D. S. Liu, S. R. Lan, and G. H. Yeo. "Uniaxial compression tests on granite and its complete stress-strain relationship at high strain rates." In Frontiers of Rock Mechanics and Sustainable Development in the 21st Century, 85–87. CRC Press, 2020. http://dx.doi.org/10.1201/9781003077510-17.
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Zhang, Weigang, Changming Xie, Xi Wei, and Min Ge. "C/C-ZrB2-ZrC-SiC Composite Derived from Polymeric Precursor Infiltration and Pyrolysis." In MAX Phases and Ultra-High Temperature Ceramics for Extreme Environments, 435–59. IGI Global, 2013. http://dx.doi.org/10.4018/978-1-4666-4066-5.ch014.
Повний текст джерелаАнотація:
Part II. Mechanical and ablation properties of the 2D C/C-ZrB2-ZrC-SiC composites with a fiber volume fraction of 17.6%, fabricated by infiltration and co-pyrolysis of blended polymeric precursors, were studied in this Part II. Flexural strength and fracture toughness of the composites were found to be influenced strongly by the thickness of the deposited pyrolytic carbon interphase, a composite with the pyrolytic carbon volume fraction of 22.3% exhibits improved bending strength and fracture toughness of 127.9 MPa and 6.23 MPa·m1/2, respectively. The pseudo-plastic strain to failure of the composite is ascribed to sliding of the interphase and pulling out of carbon fibers from the brittle ceramics matrix. Ablation properties of the composite were investigated with a plasma torch and arc-heated wind tunnel tests at temperatures above 1800~2200°C. The composite exhibits very low ablation rates of 0.18×10-3 mm/s at 1800°C and 0.37×10-3 mm/s at 2000°C in the plasma torch after 1000s testing, as compared to a similar rate of 0.30×10-3 mm/s in the wind tunnel at 1900°C after 600s testing. Ablation rates increase with increasing of temperatures from 1800 to 2200°C. The maximum ablation rate is only 1.67×10-3 mm/s in a plasma torch at 2200°C for 1000s, decreased by 71.0% as compared with the C/C-SiC composite with the same fiber and interphase contents. The 2D C/C-ZrB2-ZrC-SiC composite simultaneously showed excellent thermal shock resistance, on account of no cracks on the surface and breakage of the material being detected after these abrupt temperature increasing and long time ablations. The heating-up rate at the center of the composite specimen was found as high as above 30K/s in the plasma torch tests. Excellent ablation and thermal shock resistances of the composite can be attributed to its architecture of carbon fiber and interphase, as well as its matrix microstructures characterized by nano sized dispersions of ZrB2-Zr-SiC phases inherent formed by co-pyrolysis of three polymeric precursors. These meso- and microstructures make the composites possess very small and steady coefficients of thermal expansion (CTE) around 1.5~2.5×10-6/K and high thermal conductivities around 10~14 W/mK (which increases with increasing of temperature) from room temperature to 1300°C, respectively. Surface products and cross sectional morphologies of the composite after the ablation tests were also investigated using SEM and XRD, it was found that a homogeneous distributed and continuous glass layer composing of ZrO2-SiO2 with zirconia as a skeleton was in-situ formed. These special features of coating benefits from the merits of matrix microstructures, and inhibits the inward diffusion of oxygen and protects the composite from further oxidation and spalled off by strong gas fluid.
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Brara, Ahmed. "Critical Infrastructure: Design and Behavior of Materials Under Impact and Explosion Loads." In Critical Energy Infrastructure Protection. IOS Press, 2022. http://dx.doi.org/10.3233/nicsp220004.
Повний текст джерелаАнотація:
Critical infrastructure covering different interdependent sectors (energy, transportation, health, telecommunications, etc.) has the important role of ensuring the daily vital logistics for a comfortable and safe life of a country’s citizens. In recent times, this infrastructure is increasingly subject to various natural and man-made risks. One of the most widespread anthropogenic hazards is the phenomenon of explosions, either due to technological accidents or terrorist attacks, which effects are the most destructive to the infrastructure. Given the extreme importance of its role in the normal functioning of a country, the protection of critical infrastructure is a strategic issue. In order to minimize the vulnerability of infrastructure to these risks, one of the important measures is to take into account its security beginning at the design phase. Indeed, it has been proven that taking this measure into account ab-initio often allows improving the security of the buildings or facilities that make up this infrastructure at a lower cost. However, the optimal design of structures likely to be subjected to blast loads requires an understanding of their responses as well as the dynamic behavior of their constituent materials. This article is a state-of-the-art report on the responses of structures and their constituent materials to blast loads. Experimental techniques for obtaining very high strain rates, of the order of those generated by blast loads, are briefly described. The results of recent tests obtained with these techniques on ordinary and special concretes as well as on reinforced concrete structural elements are presented. Recent constitutive models of these materials and structures subjected to blast loads as well as numerical methods simulating the tests conducted are also reviewed.
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"Propagated Fish in Resource Management." In Propagated Fish in Resource Management, edited by JOSEPH R. KOZFKAY, DANIEL J. SCHILL, and DAVID M. TEUSCHER. American Fisheries Society, 2004. http://dx.doi.org/10.47886/9781888569698.ch41.
Повний текст джерелаАнотація:
<em>Abstract.</em>—A primary goal of put-and-take hatchery trout programs is to maximize the return to creel of stocked fish, thereby improving cost efficiency. Return to creel rates and number of days to harvest for two groups of catchable-sized rainbow trout <em>Oncorhynchus mykiss </em>were compared. The groups were produced from (1) normal Hayspur-strain broodstock, and (2) Hayspur-strain broodstock that exhibited high levels of vulnerability to angling. Ninety-four 1-h fishing trials were conducted, and capture frequency for each fish was recorded. Fish caught three or more times were retained as vulnerable broodstock. The normal broodstock was formed with other, randomly selected, Hayspur-strain brood fish that had not been subjected to fishing trials. Equal numbers of progeny from normal and vulnerable broodstocks were tagged and stocked into 16 water bodies during 2001 and an additional 16 water bodies during 2002. A total of 798 tags were returned out of 6,389 stocked during 2001. Mean first-year return rate for the vulnerable group (12.7 ± 3.5%) was not statistically different from the normal group (11.7 ± 3.8%; paired <em>t</em>-test, <em>p </em>= 0.30, df = 15). The mean time to harvest was 46.4 ± 9.8 d for the vulnerable group and 50.6 ± 10.7 d for the normal group. This disparity was not statistically different (paired <em>t</em>-test, <em>p </em>= 0.77, df = 15). For fish stocked during 2002, 700 tags were returned out of 9,593 stocked. Mean firstyear return rate for the vulnerable group (7.2 ± 2.5%) was not different from the normal group (7.4 ± 2.7%; paired <em>t</em>-test, <em>p </em>= 0.80, df = 15). There was no difference in mean time to harvest for the normal group (36.0 ± 8.0 d) and vulnerable group (38.7 ± 7.3 d; paired <em>t</em>-test, <em>p </em>= 0.45, df = 15). No performance benefit in terms of increasing return to creel or reducing time to harvest was achieved through selective breeding.
Тези доповідей конференцій з теми "High strain-rates tests"
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Lei, Shuting, Yung C. Shin, and Frank P. Incropera. "Material Constitutive Modeling Under High Strain Rates and Temperatures Through Orthogonal Machining Tests." In ASME 1997 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-1140.
Повний текст джерелаАнотація:
Abstract 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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Lall, Pradeep, Sandeep Shantaram, Mandar Kulkarni, Geeta Limaye, and Jeff Suhling. "Constitutive Behavior of SAC Leadfree Alloys at High Strain Rates." In ASME 2011 Pacific Rim Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Systems. ASMEDC, 2011. http://dx.doi.org/10.1115/ipack2011-52194.
Повний текст джерелаАнотація:
Electronic products are subjected to high G-levels during mechanical shock and vibration. Failure-modes include solder-joint failures, pad cratering, chip-cracking, copper trace fracture, and underfill fillet failures. The second-level interconnects may be experience high-strain rates and accrue damage during repetitive exposure to mechanical shock. Industry migration to leadfree solders has resulted in proliferation of a wide variety of solder alloy compositions. Few of the popular tin-silver-copper alloys include Sn1Ag0.5Cu and Sn3Ag0.5Cu. The high strain rate properties of leadfree solder alloys are scarce. Typical material tests systems are not well suited for measurement of high strain rates typical of mechanical shock. Previously, high strain rates techniques such as the Split Hopkinson Pressure Bar (SHPB) can be used for strain rates of 1000 per sec. However, measurement of materials at strain rates of 1–100 per sec which are typical of mechanical shock is difficult to address. In this paper, a new test-technique developed by the authors has been presented for measurement of material constitutive behavior. The instrument enables attaining strain rates in the neighborhood of 1 to 100 per sec. High speed cameras operating at 300,000 fps have been used in conjunction with digital image correlation for the measurement of full-field strain during the test. Constancy of cross-head velocity has been demonstrated during the test from the unloaded state to the specimen failure. Solder alloy constitutive behavior has been measured for SAC105, and SAC305 solders. Constitutive model has been fit to the material data. Samples have been tested at various time under thermal aging at 25°C and 125°C. The constitutive model has been embedded into an explicit finite element framework for the purpose of life-prediction of leadfree interconnects. Test assemblies has been fabricated and tested under JEDEC JESD22-B111 specified condition for mechanical shock. Model predictions have been correlated with experimental data.
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Qin Fei, An Tong, and Chen Na. "Dynamic behavior tests of lead-free solders at high strain rates by the SHPB technique." In 2008 International Conference on Electronic Packaging Technology & High Density Packaging (ICEPT-HDP). IEEE, 2008. http://dx.doi.org/10.1109/icept.2008.4607060.
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Lall, Pradeep, Sandeep Shantaram, Jeff Suhling, and David Locker. "Mechanical Behavior of Sn1Ag0.5Cu and Sn3Ag0.5Cu Alloys at High Strain Rates." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-93059.
Повний текст джерелаАнотація:
Electronics may experience high strain rates when subjected to high g-loads of shock and vibration. Material and damage behavior of electronic materials at high strain rates typical of shock and vibration is scarce. Previously studies have shown that second-level interconnects have a high propensity for failure under shock and vibration loads in fine pitch electronics. Exposure to shock and vibration is common in a variety of consumer environments such as automotive and portable electronics. The low strain-rate properties of commonly used SnAgCu solders, including Sn1Ag0.5Cu and Sn3Ag0.5Cu, have been found to evolve with time after prolonged exposure to high temperatures. High strain rate properties of leadfree solder alloys in the strain-rate range of 1–100 sec−1 are scarce. Previous attempts at characterizing the high strain rates properties have focused on the use of the Split Hopkinson Pressure Bar (SHPB), which enables measurements of strain rates in the neighborhood of 1000 per sec. In this paper, a new test-technique developed by the authors has been presented for measurement of material constitutive behavior. The instrument enables attaining strain rates in the neighborhood of 1 to 100 per sec. Tests are conducted at strain rates 10, 35 and 50 per sec. High speed cameras operating at 75,000 fps have been used in conjunction with digital image correlation for the measurement of full-field strain during the test. Constancy of cross-head velocity has been demonstrated during the test from the unloaded state to the specimen failure. Solder alloy constitutive behavior has been measured for SAC105, SAC305 solders. Non-linear Ramberg-Osgood model has been used to fit the material data. The Ramberg-Osgood model available in Abaqus has been used for tensile test simulation and to correlate with DIC based experimental strain data.
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Lall, Pradeep, Di Zhang, and Vikas Yadav. "High Strain-Rate Constitutive Behavior of SAC305 Solder During Operation at High Temperature." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-39518.
Повний текст джерелаАнотація:
Leadfree solders have been used as interconnects in electronic packaging, due to its environmental friendly chemical property. However, those materials may experience high strain rates when subjected to shock and vibration. Consequently, failure will occur to electronics in those situations. Therefore, knowing the material properties of lead-free solders are extremely important, but research on mechanical behaviors of those solder alloys at high strain rates are scarce. Anand’s viscoplastic constitutive model has been widely used to describe the inelastic deformation behavior of solders in electronic components under thermo-mechanical deformation. However, Anand’s model constants for the transient dynamic strain rates are scarce. In this paper, the nine material parameters to fit the Anand viscoplastic model at high strain rates have been presented. In order to develop the constants for this model, uniaxial tensile tests at several strain rates and temperatures have been completed. A constant strain rate impact hammer which enables attaining strain rates around 1 to 100 per sec has been employed to implement tensile tests and a small thermal chamber is applied to control testing temperature. High speed cameras operating at 70,000 fps have been used to capture images of specimen and then digital image correlation method is used to calculate tensile strain. Uniaxial stress-strain curves have been plotted over a wide range of strain rates (ε̇ = 10, 35, 50, 75 /sec) and temperatures (T = 25, 50, 75, 100, 125°C). Anand viscoplasticity constants have been calculated by nonlinear fitting procedures. In addition, the accuracy of the extracted Anand constants has been evaluated by comparing the model prediction and experimental data.
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West, Ashby, Garrett Venable, Michael Flanagan, Evan Harris, Brad G. Davis, F. Todd Davidson, and Joseph Hanus. "Constitutive Modeling and Validation of Sintered Metal Powders Subjected to Large Strains and High Strain Rates." In ASME 2021 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/imece2021-71461.
Повний текст джерелаАнотація:
Abstract The development of advanced small caliber weapon systems has resulted in rounds with more material penetration capabilities. The increased capabilities may mean that existing live-fire facilities will no longer be adequate for the training and certification of military and law enforcement personnel, which could result in training constraints and possibly expensive upgrades to improve the safety of existing facilities. New training ammunition manufactured from novel structural materials are needed to allow for the safe, continued use of live-fire shoot house facilities. The goal of this project is to characterize a sintered metal powder and fit a suitable constitutive model for simulation in support of numerical design. A pressed and sintered blend of copper-tin was selected as a suitable representative material for this application. Samples were tested in uniaxial compression under quasi-static conditions and elevated temperatures. Dynamic compression testing at strain rates up to approximately 105 s−1 was conducted using a split-Hopkinson bar. The results of these tests were then used to fit Johnson-Cook and Zerilli-Armstrong strength models to the test data. The models were fit by selecting points from test data at different strain rates and elevated temperatures. This system of equations was then solved for each model while using the same test data to ensure a fair comparison of the results. A Mie-Gruneisen equation of state for the material was estimated using a rule of mixtures and existing shock and particle velocity data. Taylor cylinder tests were conducted and the rate of change in length was measured using high-speed video. Simulation of the Taylor tests was conducted using the developed strength and equation of state model and compared to the experimental results for model validation and comparison. Both the Johnson-Cook and Zerilli-Armstrong models resulted in less than 1% error of the Taylor cylinder results before material fracture. Further development of a fracture model for this material is recommended for use in high strain rate modeling applications.
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Munson, Douglas, Timothy M. Adams, and Shawn Nickholds. "Determination of Tensile Elastic Modulus in High Density Polyethylene Piping at Seismic Strain Rates." In ASME 2012 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/pvp2012-78777.
Повний текст джерелаАнотація:
For corroded piping in low temperature systems, such as service water systems in nuclear power plants, replacement of carbon steel pipe with High Density Polyethylene pipe is a cost-effective solution. Polyethylene pipe can be installed at much lower labor costs than carbon steel pipe and High Density Polyethylene pipe has a much greater resistance to corrosion. Data was developed by the three testing tasks for use in the seismic design of above ground High Density Polyethylene Piping systems. This paper presents the results of testing to determine the relationship between tensile elastic modulus and strain rates commensurate with seismic loading. This is accomplished by first establishing a seismic strain rate for High Density Polyethlene using detailed finite element analysis. The results of this analysis are used to establish a test matrix tensile testing. Next, tensile tests are conducted using standard ASTM D-638 Type III tensile specimens. The tensile testing is conducted at three pull speeds to establish a basic relationship between tensile elastic modulus and strain rates. This relationship is then used to calculate the modulus at the strain rates expected under seismic loading. This paper presents the results of this testing and the suggested tensile modulus for use in seismic analysis.
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Hojjati, Reza, Matthias Steinhoff, Steven Cooreman, Filip Van den Abeele, and Patricia Verleysen. "Effects of High Strain Rates on Ductile Slant Fracture Behaviour of Pipeline Steel: Experiments and Modelling." In 2016 11th International Pipeline Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/ipc2016-64332.
Повний текст джерелаАнотація:
Good material properties are required to ensure the safe and reliable design of oil and gas transmission pipelines. The main objective of the study, presented in this paper, is to examine the influence of high strain rates on the hardening and ductile fracture behaviour of an API 5L X70 pipeline steel by means of a combined experimental/numerical approach. For this purpose, the impact toughness of the material is assessed using instrumented Charpy V-notch (CVN) impact tests at a wide range of temperatures. To characterize the mechanical response of an X70 pipeline steel subjected to high strain rates, split Hopkinson tensile bar (SHTB) experiments are performed. These experiments allow deriving the true effective stress versus plastic strain, strain rate and temperature. Both the CVN and SHTB tests results are used for fundamental material research and constitutive material modelling. For the numerical simulations, the modified Bai-Wierzbicki (MBW) model is applied. The MBW model represents the influence of the stress state on the plastic behaviour and the onset of damage, and quantifies the microstructure degradation using a dissipation-energy based damage evolution law. The model hence allows for an accurate prediction of the ductile fracture mechanisms. The combined experimental/numerical approach is then used to simulate the upper shelf ductile fracture behaviour of an API X70 pipeline steel for high strain rate and Charpy tests. Based on the available experimental data, a new parameter set has been determined. Using these new material parameters, good correlations between numerical simulations and experimental observations have been obtained for both the split Hopkinson tensile bar tests and the Charpy impact tests.
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Sohoni, G. S., M. V. Walame, V. Tandon, R. S. Mahajan, and S. Raju. "Dynamic Behavior Characterization of Lead at High Strain Rates Using High Speed Photography for Finite Element Simulation." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-82693.
Повний текст джерелаАнотація:
This paper reviews experimental as well as computational techniques for determining stress-strain characteristics of materials at high strain rates. Quasi-static and dynamic compression tests were performed on standard Lead (Pb) specimens of three different L/D ratios, 0.8, 2 and 3. A Drop tower system was used to achieve different strain rates along with high-speed camera to capture the vertical and radial deformation of specimen and accelerometers to capture load data. The results obtained from the experiments were processed to generate dynamic stress-strain curve for Lead under different strain rate conditions. It was observed that the dynamic stress increases with increasing strain rate. The information gained is valuable for validating constitutive models.
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Isakov, Matti, Jeremy Seidt, Kauko O¨stman, Amos Gilat, and Veli-Tapani Kuokkala. "Characterization of a Ferritic Stainless Sheet Steel in Simple Shear and Uniaxial Tension at Different Strain Rates." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-63141.
Повний текст джерелаАнотація:
In this study the mechanical properties of ferritic stainless steel EN 1.4521 (AISI 444) were characterized in uniaxial tension and simple shear. The specimen geometries were designed so that tests could be carried out both with a conventional uniaxial materials testing machine and at high strain rates with the Tensile Hopkinson Split Bar method. During the tests, specimen surface deformation was measured using a three dimensional digital image correlation technique based on a two-camera stereovision setup. This technique allowed direct measurement of the specimen gauge section deformation during the test. Test results indicate that the selected approach is suitable for large strain plastic deformation characterization of ductile metals. The stress-strain data obtained from the simple shear tests shows a correlation with the tensile test results according to the von Mises effective stress-strain criterion. Since necking is absent in shear, test data can be obtained at considerably higher plastic strains than in tension. However, the final fracture occurs under a complex loading mode due to the distortion of the specimen geometry and multiaxial loading introduced by the simple shear arrangement. Test results also show that reliable material data can be obtained at high strain rates.
Звіти організацій з теми "High strain-rates tests"
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Cox, Bradley. Fiber Bragg Grating validation tests to measure high-strain rates at elevated temperatures. Office of Scientific and Technical Information (OSTI), September 2015. http://dx.doi.org/10.2172/1215806.
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TENSILE BEHAVIOUR OF TMCP Q690D HIGH-STRENGTH STRUCTURAL STEEL AT STRAIN RATES FROM 0.00025 TO 760 S-1. The Hong Kong Institute of Steel Construction, March 2022. http://dx.doi.org/10.18057/ijasc.2022.18.1.7.
Повний текст джерелаАнотація:
The application of Q690D high-strength structural steel (HSSS) has been increasing in engineering structures. The lack of knowledge of the strain rate behaviour limits the application to the extreme loading conditions such as blast and impact loadings. This paper presents a series of tensile tests on the dynamic tensile behaviour of Q690D HSSS produced through the thermo-mechanical control process (TMCP). The stress-strain relationships of TMCP Q690D in the strain rate range of 0.00025 to 760 s-1 were measured by using the universal and servo-hydraulic high speed testing machines. The experimental results verified the sensitivity to strain rate of TMCP Q690D and the dynamic increase factor (DIF) for yield stress is identical to that of QT (Quenched and Tempered) S690 HSSS. However, TMCP Q690D behaves in a much different way in the strain hardening stage. The commonly-used Cowper-Symonds model was calibrated for the DIFs of yield stress and ultimate tensile strength. The Johnson-Cook (J-C) model was modified and a new rate-dependent constitutive model was proposed. The proposed model was validated successfully to predict the true stress-strain relationship, providing better prediction results than the modified J-C model.