As outlined, different average strain rates have been achieved by using different specimen lengths, precisely 2, 4 and 8 mm with 4 mm constant diameter. Low to high strain rate characterization of dp600, trip780. Quasistatic and dynamic experiments at strain rates up to 350 s1 was performed with endloaded, rectangular offaxis compression and. Strain rate sensitivity and crash modeling of high strength. Taamjeed rahmaan a thesis presented to the university of waterloo in fulfillment of the thesis requirement for the degree of master of applied science in mechanical engineering waterloo, ontario, canada, 2015 m.
Advanced diagnostics, such as in situ xray scattering, allow timeresolved material characterization in the shortlived high pressure state, including crystal structure phase, elastic compression, the size of microstructural features, and defect densities. In the dynamic tests, the fastcam was used to measure the strains, for costefficiency reasons. Tensile properties the basic tensile properties of materials in tension are determined at one rate of straining. However, test configurations in the subhopkinson bar strain rate regime 4 which covers the majority of the rates of automotive interest has not yet been standardized, and are still under. Academics in material characterization at high strain. Material characterization at high strain by adapted. Since little is known about the dynamic failure of adhesive materials, this study investigates the behavior and failure modes of adhesive materials and joints subjected to ballistic impact. Material property characterization of ultra high performance concrete publication no. Therefore not at all of book tend to be make you bored, any it makes you feel happy, fun and unwind.
This paper presents a material characterization methodology to determine the material parameters of a given material constitutive model from a given high strain rate experiment. Degrieck ghent university, faculty of engineering, department of mechanical construction and production, belgium abstract in this contribution, attention. High strain rate testing methods have been advancing in recent years 2, 3 in part due to the interest of exploiting strain rate effect in steels. The current research has considered the characterization of the high strain rate constitutive response of three steels. High strain rate elastic and fracture characterization of. Material characterization at high strain rate by hopkinson bar tests and finite. Computer simulation, especially molecular dynamics, provides insight into the. High strainrate characterization of magnesium alloys.
Reis 3, 1 cemmpre, department of mechanical engineering, university of coimbra, 3030194 coimbra, portugal. Characterization of adhesive materials under high strain rate loading. High strain rate characterization of advanced high. The characterization methodology is based on an inverse technique in which an inverse problem is formulated and solved as an optimization procedure. As a composite of polymers, the properties of uhmwpe are timedependent. It is desired by research sponsors to know the properties of the material at high strain rates, in order to simulate the use of these materials in computer. High strainrate soft material characterization via inertial cavitation. Material characterization at high strain rate by hopkinson. High rate characterization of low impedance materials using a.
Consequently, the study and modelling of material behavior in such conditions has been promoted. Dynamic testing of several materials was performed. Characterisation of the high strain rate properties of. Diverse experimental techniques at high strain rates are available, such as the droptest, the taylor impact test or the split. The characterization of the dynamic behaviour and damage processes induced in brittle materials under highstrainrate compression and. Material characterization of single crystalline cu subjected. Temperature dependence of material behaviour at high strainrate. High strain rate materials characterization for crash. Characterization of adhesive materials under high strain. Fhwahrt06103 august 2006 research, development, and technology turnerfairbank highway research center 6300 georgetown pike mclean, va 221012296. This method was discussed in a technical report written by japanese scientists akihiro uenishi, 2003 on material characterization at high strain rates of sheet materials. Data for high strain rate testing of sheet steel, structural plastic and crushable foams is shown.
Mechanical behaviour of glass and carbon fibre reinforced. Pdf characterisation of the high strain rate properties of advanced. Inverse methods for the mechanical characterization of. High strain rate characterization of polymers aip publishing. To meet these opportunities, prospective adhesive materials would need to perform satisfactorily in high strain rate loading situations such as impact. Quasistatic and high strain rate compression tests are conducted on the matrix alloy and the composite. The tensile tests were conducted at strain rates of approximately 5. Intermediate strain rate material characterization with. Robust models that capture the physics of high rate material response are required for developing predictive capability for highly dynamic events. High strain rate testing services the objective of the testing services is to define the basic material properties of solid materials at medium and high rates of strain. Metal deformation and phase transitions at extremely high. High strain rate characterisation of composite materials.
View academics in material characterization at high strain rates on academia. Material characterization of leadfree sac solder alloys at high strain rates with finite element analysis. Apr 22, 2019 by examining the evolution of stress, strain and strain rate, the latter two parameters measured using twodimensional digital image correlation dic, it is demonstrated that dynamic simple shear deformation consists of four distinct stages. Characterization of uhmwpe laminates for high strain rate applications. Chief among the techniques to measure the dynamic stress strain response of materials is the split. High strain rate sensitivities of the dc steel grades have been also found e. High strain rate characterization of advanced high strength. It has long been known that the dynamic properties of materials differ from those under static loading, and since the pioneering work of the hopkinsons, numerous. Establish high strain rate mixed mode traction separation laws. High rate characterization of low impedance materials. Characterization of high strain rate dependency of 3d cfrp materials. Improved experimental and diagnostic techniques for dynamic tensile stress strain measurement with a kolsky tension bar ying qiu, colin m loeffler, xu nie et al.
Stress in the hopkinson bar is measured by using an elastic element in series with the specimen of interest. High strain rate elastic and fracture characterization of isotropic and orthotropic materials with and without nano fillers view open dissertation finalized with updated equations and figures and page numbers. Characterization and modeling of the high strain rate. Material characterization at high strain by adapted tensile tests. High strain rate fibermatrix interfacial traction laws. Characterization of masonry behavior under high strain rates 3 static tests, strain gauges were used to measure the strains in the specimen. High strain rate material characterization of al 7075t651 by. Material characterization of leadfree sac solder alloys at. Temperature dependence of material behaviour at high. Determine high strain rate properties for steels currently used or anticipated to be used in automotive structures refine material models to better represent material behavior refine fea modeling approaches develop advanced analytical tools to compare fem simulations and experiments. Strain rate characterization of advanced high strength steels.
The strain is then held constant while the sample is cooled down to 10. The relationship between armour steel mechanical properties, their specifically mechanical metallurgy, and ballistic performance is explained, where such performance is primarily determined by material strength, hardness and high strain rate behaviour. High strain rate experiments materials engineering. In support of the autosteel partnership asp, strain rate characterization project, ornl will conduct a high rate experimental tests and analysis of base material specimens in tension configuration. Mechanical characterization of eurofer97 in tension at. High strain rate characterization of polymer composite materials has been limited due to difficulties in the measuring equipment. The low strain rate tests were conducted using an instron hydraulic testing machine. In this context, a better knowledge about the mechanical properties of these materials is expected, especially when submitted to dynamic loads. Pdf the demand for increased vehicle safety has become a matter of considerable concern of users. High strain rate experiments introduction high strain rate experiments on materials dynamic loading causes signi cant deformation and damage of materials due to the kinetic energy carried by a mass as compared to quasistatic loading in dynamic loading stress is a function of the particle velocity, i. The strain rate affects also the ductile fracture conditions as well as the transition temperature to clearage fracture. Material characterization at high strain rate by hopkinson bar tests and finite element optimization. Polymeric materials are subjected to dynamic loading and high strain rate deformation in a variety of important applications such as aircraft and automotive components, as well as during high speed processes such as extrusion.
Numerical modelling of footwear to protect against antipersonnel landmines requires dynamic material properties in the appropriate strain rate regime to accurately simulate material response. Characterization of material for impact is not standardized modeling technology is not adequate for aggressive weight reduction gap exists in the fundamental understanding and the predicting capability for ahss in crash this gap is shared by other high strength materials, as well what is the range of strain rates in impact. High strain rate characterisation of composite materials eriksen, rasmus normann wilken publication date. Material characterization of single crystalline cu. The stress strain response of these steels were measured at seven strain rates between 0. Material characterization at high strain rates for optimizing car body structures for crash events. Material characterization of single crystalline cu subjected to high strain rates and high temperatures for multiscale simulation yujin seong1, youngkyu kim1, im doo jung1, sungho kim2, see jo kim3, seonggon kim4, hak jun kim5, and seong jin park1, 1department of mechanical engineering, pohang university of science and technology, pohang 37673. High strain rate characterization of advanced high strength steels by alan c. High strain rate material characterization of al 7075t651 by modified taylor impact test and velocity interferometry. In the present work, dynamic tests have been performed on aisi 1018 cr steel specimens by means of a split hopkinson pressure bar shpb. Keywords specimen geometry highspeed tensile test servohydraulic testing machine stress wave analysis material characterization stressstrain curve. Pdf in the automotive industry a lot of energy is put into the. A modification on the yld20002d yield function allowed to develop a unique strain rate dependent anisotropic yield function that captures the yielding and anisotropic behavior of the material at multi strain rates.
The influence of increasing strain rate on the mechanical behavior and deformation substructures in metals and alloys that deform predominately by slip is very similar to that seen following quasistatic deformation at increasingly lower temperatures or due to a. Pdf characterization of high strain rate dependency of 3d. Pdf characterization of high strain rate dependency of. High strain rate test methods methods for characterization of material property degradation damage evolution under high rates methods for failure characterization at high rates databases of material properties constitutive models for fem simulations. Missioncritical applications dynamic high strain rate testing is required by numerous standards from astm, iso, en, din, bs and afnor.
Olymeric materials have been used widely in engineering applications due to their low production cost and light weight. Jul 31, 2019 in recent years, interest in material characterization at high strain rates while varying the temperature has been continuously increasing. Silicon carbide sic ceramics are one of the best candidates for high temperature structural applications. Price sheet for high strain rate characterization pdf related web page with pictures and additional links html. Over the past several decades, the high strain rate behavior of various polymeric materials has been extensively studied revealing critical importance of multiple distinct relaxation processes as well as multiple energy storage and dissipation pathways on the macroscopic mechanical responses. The knowledge of the elastic behavior is essential to correctly predict these springbacks during forming. High strain rate characterization of shock absorbing. The strain rate dependence of compressive response is determined for aluminum alloyhollow. Highrate test systems are deployed worldwide to produce accurate, reliable results for leading companies in industries as diverse as automotive, aerospace, rail, consumer products, and construction materials.
Pdf material characterization at high strain rate by. In sheet metal forming operations, frequently high levels of strain are obtained. Any projectile nose shape is incorporated using its diameters at 25, 50 and 75% of the nose length and is linearly interpolated for the other nose positions. High temperature vibration fatigue life prediction and high. May 18, 2012 robust models that capture the physics of high. A positive strain rate sensitivity was observed for each of the steels.
At strain rates greater than 400 s 1, this trend reverses, reducing failure stresses and sti ness, and seeing an increase in failure strain. Thompson a thesis presented to the university of waterloo in fulfillment of the thesis requirement for the degree of master of applied science in mechanical engineering waterloo, ontario, canada, 2006 alan c. Characterization and modeling of the elastic behavior of a. Low density and excellent machinability of mg alloys make them good candidates for lightweight constructions of components in automotive industry. The influence of increasing strain rate on the mechanical behavior and deformation substructures in metals and alloys that deform predominately by slip is very similar to that seen following quasistatic deformation at increasingly lower temperatures or due to a decrease in stackingfault energy. High strain rate vhs systems characterize strain rate dependent materials such as automotive crash structures at test speeds of up to 25ms.
The model developed was validated using finite element simulations of the experimental tests. In particular, jigs and fixtures can be subject to inertial disturbances present at speeds up to and above 2 ms. Material property characterization of ultra high performance concrete 6. They found that up to strain rates of 400 s 1, there is an increase in stress and sti ness at failure and a decrease in strain with an increase in strain rate. High strain rate properties of metals and alloys r.
Koerber et al 11 high strain rate characterization of unidirectional carbonepoxy im78552 in transverse compression and inplane shear using digital image correlation. New developments in material testing at very high strain rates. Mechanical characterization of alsi12 foams at high strain rates. However, due to the inherent drawbacks of hardness, porosity, and brittleness for ceramic materials and the specific application environment involving exposure to oxidation fuels, or aero heating, reinforcements of carbon nanotubes cnts and tantalum carbide tac are considered to. This technique is capable of achieving the highest uniform uniaxial stress loading of a specimen in compression at nominally constant strain rates of the order of 10 3 s. One develops a strength constitutive model for a particular material by measuring its mechanical properties over a range of temperatures, strain rates, and stress states. Determination of material and failure characteristics for. Pdf material characterization at high strain rates for. High rate characterization of 10% and 20% ballistic gelatin, commonly used as a tissue simulant, has been compared with existing data for soft bovine tissue. The strain rates chosen are in the range of 1100 persecond which are typical at second level interconnects subjected to dropshock and vibration environments. A splithopkinson pressure bar is used for high strain rate testing.
These tests, together with the new experimental protocol, permit to accurately reveal and measure the material behaviour strain rate sensitivity, which proved to be large in the 45 direction. This research includes the high strain rate material characterization of innolot as the alloy ages at an elevated temperature of 500c. Low to high strain rate characterization of dp600, trip780, aa5182o by m. Pdf material characterization at high strain rates for optimizing. Material may be provided as dogbone specimens, or plaques. Mechanical characterization of different aluminium foams. As shown in figure 1, the sample is preheated to 70. Proceedings of the asme 2016 international mechanical engineering congress and exposition. Characterisation of the high strain rate properties of advanced high strength steels j. Research of materials high strain rate fibermatrix interfacial traction laws how we fit technical approach key accomplishments key goals major results impact materials bydesign process future directions in 2017.
High strain rate characterization of magnesium alloys. Characterization of uhmwpe laminates for high strain rate applications frederick philip cook abstract the research presented in this thesis represents an e ort to characterize the properties of ultra high molecular weight polyethylene uhmwpe. In recent years, interest in material characterization at high strain rates while varying the temperature has been continuously increasing. A kolsky tension bar technique using a hollow incident tube o guzman, d j. Walley2 the high strain rate dependence of the flow stress of metals and alloys is described from a dislocation mechanics viewpoint over a range beginning from conventional tensioncompression. The high strain rate mechanical properties of several classes of. Although a number of techniques have been developed to measure material properties at high strain rates, the splithopkinson pressure bar 5558, or kolsky bar, has now become ubiquitous for materials characterization between 500 and 10 4 s. Bouquerel2 1department of mechanical construction and production, faculty of engineering, ghent university, belgium 2department of metallurgy and materials science.
Chief among the techniques to measure the dynamic stressstrain response of materials is the splithopkinson pressure bar. High strain rate characterization of a glassepoxy composite. The control strain cyclic test was designed under dma strain rate mode. Several materials foamed metals, honeycombs and polymers are used in existing protective boots, however published data at high strain rates is limited. Mechanical characterization of soft materials at high strainrates is challenging due to their high compliance, slow wave speeds, and.
Characterization of uhmwpe laminates for high strain rate. Constitutive equations under dynamic loading, high strain rate gradients are initiated in the material which are accompanied by a change in temperature due to the adiabatic character of high rate. The objective is therefore on the one hand the characterization of the elastic response of the material under different conditions and on the other hand the definition of a model that describes the material behavior with as much precision as possible. Pdf inverse methods for the mechanical characterization. Stress in the hopkinson bar is measured by using an elastic element in series with the. Use of simulated experiments for material characterization of brittle. It was found that, as the nominal strength of the steel increased, the strain rate sensitivity decreased. Although both high strain rate 18 and high pressure 19,20 tend to increase the t g and modulus of polymers, the classification of glass and rubber is expected to remain valid at the impact of a. The shear tests were conducted at strain rates of approximately 910 isec, 2 isec and 500 isec. There is a gap in the literature on the strain rate characterization of material properties at intermediate strain rates in the range of 10. From these dynamic results, a formidable strain rate sensitivity of the material for the reason that strain rate is only varying from 500 to 1500 s. Dynamic material characterization by combining ballistic. Material property characterization of ultrahigh performance. Characterization of adhesive materials under high strain rate.
40 1435 793 731 1396 1232 368 103 1468 787 741 362 1241 1404 837 1449 174 1328 800 197 623 108 1312 63 1362 1621 389 726 1384 1430 1455 597 406 212 895