However, the methods require the use of largescale testing machines. When the striker bar impacts the copper disk, a nondispersive ramp pulse propagates in the. Mohamad dyab, university of maryland eastern shore mohamad dyab currently works at the university of maryland eastern shore umes on a research project on modeling and simulation of wind turbines for structural health monitoring purposes. By ansyslsdyna i am trying to simulate the splithopkinson pressure bar shpb test. Feasibility of rock dynamic properties by split hopkinson pressure bar shpb was experimentally and numerically evaluated with ansyslsdyna. The effects of different diameters, different loading rates, and different propagation distances on wave dispersion of input bars in shpb with rectangle and halfsine wave loadings were analyzed. The original hopkinson device with only one cylindrical bar was modified by kolsky two bars for indirect measurements on both sides of the specimen. Finally, we found an unclassified army materials and mechanic research booklet titled design and operating characteristics of a split hopkinson pressure bar apparatus.
The split hopkinson pressure bar shpb technique is analyzed during the initial stages of loading by means of. Deformation behavior of artificial rock in the split. Singh d, salem j and widjaja s eds mechanical properties and performance of engineering ceramics and composites vi. Split hopkinson bar simulation using abaqus simulator. The strain rate is found to be controlled by the stress and strain of the deforming specimen, geometry the length and diameter of specimen, impedance of bar, and impact velocity. Experimental and numerical investigations on the use of. The strain rate sensitivity of neoprene is characterized using a modified split hopkinson pressure bar shpb system at intermediate 50 s1, 100 s1 and high 500 s1, s1 strain rates. Also, numerical simulations were conducted in abaqus software. The shsb has been developed a variety of techniques, for, the hatfor exampleshaped circular or flat, doublenotch, and punch with or without notch techniques. Evolution of specimen strain rate in split hopkinson bar test.
At present, the splithopkinson pressure bar test, truetriaxial rockburst test, etc. There is no iso or astm specification for compression testing on split hopkinson pressure bar. The speed of the striker bar corresponded to that in the shpb experiment for a particular strain rate. Dynamic behaviour of polymers at high strainrates based. Although shpb technique has been verified for metallic materials, the validity and accuracy of shpb results for nonmetallic materials have not been thoroughly studied. A set of split hopkinson pressure bar tensile tests were conducted. This apparatus consists of four long pressure bars, i. Written in matlab r, the code can be freely distributed.
However, extreme caution needs to be exercised while testing these highstrength ceramics at high strain rates. Beyond hopkinsons bar philosophical transactions of the. A split hopkinson pressure bar technique to determine. I am modelling a shpb assembly together with the specimen, and i am having trouble with placing the loads,creating the boundary constrain between the incident, transmitter bar and the specimen. The modern shpb system is widely used in the laboratory studies on stress waves in various types of solids such as metals, rocks, concrete, and so on. Abaqus software was used for the numerical simulation. Bonded particlefinite element simulation of rock in split. The solid model of the apparatus is built using cad software solidworks.
The specimen is placed between the ends of two straight bars, called the incident bar and the transmitted bar. Abaqus simulation split hopkinson bar 15ms impact youtube. Inverse characterization of material constitutive parameters for. Aug 28, 2014 c viscoelastic split hopkinson pressure bar simulation. Laboratory experiments are more practical, reliable, and intuitive. It can test the materials at various strain rates in the range of 10 to 10 4 sec. This technique modifies the conventional split hopkinson bar apparatus by placing a thin copper disk on the impact surface of the incident bar. The abaqus explicit dynamics simulation of wave propagation during split hopkinson pressure bar shpb test. I am also trying to simulate a split hopkinson pressure bar test on a glass sample. The split hopkinson pressure bar shpb has been in use for many years to measure the compression response, principally of metals, but also more recently for much softer materials such as polymers. The classical split hopkinson pressure bar system is then composed of two axial bars incident bar and transmitter bar and a striker bar launched by a gas gun. In order to perform experimental identification of high strain rate material models, engineers have only a very limited toolbox based on test procedures developed decades ago.
The axial strain measured directly from the strain gage and obtained from the process analysis of threewave method were compared. Download scientific diagram principle of split hopkinson pressure bar. Schematic of split hopkinson pressure bar the bars used in a split hopkinson pressure bar setup are traditionally constructed of a high strength metal such as 4340 steel or a nickel alloy such as inconel. Specimen stress equilibrium in split hopkinson pressure bar tests of ceramics at high strain rate. Structural effects on compressive strength enhancement of. Evolution of specimen strain rate in split hopkinson bar.
Critical appraisal of limiting strain rates for testing. Review and cite splithopkinson bar protocol, troubleshooting and other methodology information contact experts in splithopkinson bar to get answers. The results show that the dispersion effect on the. Stress equilibrium in the split hopkinson pressure bar test x. Li school of mechanical, aerospace and civil engineering, pariser building, the university of manchester, sackville street, manchester m 9pl, uk abstract. Aug 28, 2014 the split hopkinson pressure bar shpb has been in use for many years to measure the compression response, principally of metals, but also more recently for much softer materials such as polymers. Pressure waves in soils using a splithopkinson pressure bar. The specimen strain rate in the split hopkinson bar shb test has been formulated based on a onedimensional assumption. Nov 10, 2012 split hopkinson bar simulation using abaqus simulator. Dynamic behaviour of polymers at high strainrates from 101 to 104 s1 is. By ansyslsdyna i am trying to simulate the split hopkinson pressure bar shpb test. Split hopkinson pressure bar shpb abaqus simulation. The behavior of rock under impulse loadsa study using the hopkinson split pressure bar method, doctor thesis, technical university, otaniemihelsinki, acta polytechnical scandinanca 1969.
Dynamic behaviour of polymers at high strainrates based on. Using the split hopkinson pressure bar to validate. The conventional split hopkinson pressure bar apparatus is modified by shaping the incident pulse such that the samples are in dynamic stress equilibrium and have nearly constant strain rate over most of. Stress equilibrium in the split hopkinson pressure bar test. We present pulse shaping techniques to obtain compressive stressstrain data for brittle materials with the split hopkinson pressure bar apparatus. Split hopkinson pressure bar graphical analysis tool duration. Finite elements method in split hopkinson pressure bar developing process rotariu adrian, bugaru mihai, chereches tudor department of mechanics, department of mechanics military technical academy, politehnica university of bucharest george cosbuc avenue 8183, bucharest, splaiul independentei 3, bucharest romania. A schematic of the hopkinson pressure bar is illustrated in figure 1. Can anyone give me details idea, about what kind of contact i have to define between striker bar and incident.
A new offering in this field is our surepulse software which simplifies the data acquisition effort for hopkinson bar testing. Download scientific diagram finite element model of the split hopkinson. Abaqus modelling of stress waves in a split hopkinson presure. Split hopkinson pressure bar wave deconvolution polyurea intermediate strain rates abstract the strain rate sensitivity of polyurea is characterized using a modi. The analysis of the results from the split hopkinson pressure bar was based on the. Finite element simulation for design verification of a. We used two quartz piezoelectric force transducers that were sandwiched between the specimen and experimental bars respectively to directly measure the weak wave. Finite element model of the split hopkinson pressure bar test system. The split hopkinson pressure bar shpb was first designed for testing of ductile materials. Hello i am a student of the university of manchester. Full shpb tests with viscoelastic bars were simulated and the data reduced to determine the material properties of hyperelastic specimens. The split hopkinson pressure bar shpb is also called the davies bar or the kolsky bar after those who developed the modern shpb system on the basis of the original hopkinson bar. The design is validated by extensive finite element simulation using abaqus. Although there are various setups and techniques currently in use for the splithopkinson pressure bar, the underlying principles for the test and measurement are the same.
When the striker bar came in contact with the incident bar, a stress wave was set in motion figure 1. About the dynamic strength enhancement of concretelike. Split hopkinson pressure bar an overview sciencedirect. The geometry was the same as in the experimental setup figure 1b. Is there anyone who have experience on doing split. Elevated rates of strain, such as those found in impact and explosive applications, have been shown to induce phenomena such as strain hardening and phase transitions that can significantly affect the strength of most materials 14. Split hopkinson bar technique the construction of a compression shpb system is illustrated schematically in fig. Chief among the techniques to measure the dynamic stressstrain response of materials is the splithopkinson pressure bar.
The highest strain rate at which ceramics can be tested using an shpb without violating the underlying assumptions. The striker bar was set in motion to initialize the fe simulation. Advance instrument incs apparatus of shb is the direct determination of dependence of the deformation stress strain curves and the strain rate strain curves. Feasibility of rock dynamic properties by splithopkinson pressure bar shpb was experimentally and numerically evaluated with ansyslsdyna. Finite element modeling of strain rate experiment for soft. The specimen is sandwiched between the transmission and incident bar. Is there anyone who have experience on doing split hopkinson pressure bar test simulation by ansys lsdyna. Split hopkinson pressure bar graphical analysis tool documentation, version 1. I have to test its dynamic imact behaviour using split hopkinson pressure bar, i have done the experiment and have the results. Providing learning opportunities by designing a split hopkinson pressure bar mr. Structural effects on compressive strength enhancement of concretelike materials in a split hopkinson pressure bar test. Material testing at high strain rate using the split hopkinson pressure.
Split hopkinson pressure bars dear all, i was wondering whether anyone here knows any companies or institutions which can supply the complete split. An optical method of strain measurement in the split. Numerical split hopkinson pressure bar nshpb tests based on the reconstitution method have been used to study the structural effects. If you have an engineering background, it is likely that you have come across one of the most famous testing methods. The conventional split hopkinson pressure bar apparatus is modified by shaping the incident pulse such that the samples are in dynamic stress equilibrium and have nearly constant strain rate over most of the test duration. The system can be equip with high temperature heating system and cooling system.
Jul 20, 2017 im graduating in mecanical enginiering and my final project is about hopkinson lressure bar i read all you wrote but when i run the file. Limiting conditions for compression testing of flat specimens in the. Can anyone give me details idea, about what kind of contact i have to. Design of a split hopkinson bar apparatus for use with. Pdf a special split hopkinson pressure bar shpb under confining pressure and temperature, triaxial static. The compressive split hopkinson pressure bar shpb technique allows the stresses on each end of the specimen to be measured individually. The split hopkinson pressure bar shpb is being widely used to determine the dynamic compressive strength of ceramics and ceramic composites. Example 8 hopkinson bar summary precise data for high strain rate materials is necessary to enable the accurate modeling of highspeed impacts. Split hopkinson pressure bar test engineering breakdown. I am currently modelling a split hopkinson pressure bar tensile test. Finite element simulation for design verification of a small. The elastic wave i generated on the input bar does not contain reflected wave. Pulse shaping techniques for testing brittle materials.
The designed split hopkinson bar consists of two metallic bars with a specimen placing in between, a striker assembly, an air compressor, instrumentation and a data acquisition system. Using split hopkinson pressure bars to perform large. To go even higher, we must employ projectiledriven impacts that induce stresswave propagation in the sample materials. Abaqus, matlab to analyze and design a realistic system and its. Although there are various setups and techniques currently in use for the split hopkinson pressure bar, the underlying principles for the test and measurement are the same. The results obtained by numerical investigation finite elements of shpb are compared with the inplane and outofplan compression test of a woven composite. Split hopkinson pressure bar shpb abaqus simulation youtube. Gorharn faculty of technology, the open university, walton hall, milton keynes, mk7 64.
The use of the split hopkinson pressure bar techniques in high strain rate materials testing. Deformation behavior of artificial rock in the split hopkinson pressure bar test. Inverse characterization of material constitutive parameters. For splithopkinson pressure bar test simulation by ansys. One of the experimental techniques for characterising materials under the effect of high strain rates is the split hopkinson pressure bar shpb test. Providing learning opportunities by designing a split. Development of a split hopkinson tension bar for testing stressstrain response of particulate composites under high rates of loading except where reference is made to the work of others, the work described in this thesis is. The best example is the socalled split hopkinson pressure bar based on the bar concept introduced 100 years ago by bertram hopkinson to measure blast pulses. Effect of structurallyinduced lateral confinement on split hopkinson. Using the split hopkinson pressure bar to validate material.
Pdf split hopkinson pressure bar test and numerical analysis of. Hi emeka, i performed the shpb simulation for one of my materials last year. Feb 01, 2018 the abaqus explicit dynamics simulation of wave propagation during split hopkinson pressure bar shpb test. Eight elements were used across the specimen radius, whereas 10 elements were. Dynamic behaviour of polymers at high strainrates based on split hopkinson pressure bar tests y.
Split hopkinson pressure bar is an apparatus that is used to study materials. Mohamad dyab, university of maryland eastern shore. An opensource split hopkinson pressure bar graphical data analysis tool has. Split hopkinson pressure bar simulation using abaqus imechanica. Is there anyone who have experience on doing splithopkinson. The split hopkinson pressure bar shpb continues to be one of the most common methods of testing materials at medium rates of strain. Split hopkinson bar is an inexpensive device for performing high strainrate experiments.
Finiteelement simulations of split hopkinson test of ti. You have to use instance and constraints options in asse. The device is composed of a hydraulic piston along with nylon input and output bars. Split hopkinsonson bar test appartus advance instrument inc. Experimental and numerical evaluation of rock dynamic test. The shsb has been developed a variety of techniques, for, the hatfor exampleshaped circular or flat, double. Article information, pdf download for evolution of specimen strain rate in split hopkinson bar test open. The specimen strain rate in the split hopkinson bar shb test has been. Split hopkinson pressure bar graphical analysis tool file. Split hopkinson pressure bar shpb technique has been used widely to measure the dynamic strength enhancement of concretelike materials at high strainrate between 10 1 and 10 3 s. Abaqus modelling of stress waves in a split hopkinson. The finite element fe setup of the shpb was akin to the experiment.
This paper presents a split hopkinson pressure bar technique to obtain compressive stressstrain data for rock materials. Jun 03, 2016 one of the experimental techniques for characterising materials under the effect of high strain rates is the split hopkinson pressure bar shpb test. Split hopkinson pressure bar graphical analysis tool. Pulse shaping techniques for testing brittle materials with a. Using split hopkinson pressure bars to perform large strain. The facility is designed for split hopkinson bar compression high strain rate testing. This week a brief introduction to the basics of this technique is covered. Clearly, the apparent strainrate enhancement of material strength due to structural effects cannot be considered as a genuine strainrate effect. Im using abaqus explicit and modelling the setup as.
The split hopkinson shear bar shsb test is a modification of the high rateimpact test using a split hopkinson pressure bar shpb. Results comparison for hatshaped, doublenotch and punch. Various constitutive models were used in abaqus to study different. Although shpb technique has been verified for metallic materials, the validity and accuracy of shpb results for nonmetallic materials have not been. When the striker bar impacts the copper disk, a nondispersive ramp pulse propagates in the incident bar and produces a nearly. In this study, the strains of artificial rock were analyzed in order to estimate the deformation behavior of rocklike materials in the shpb test. Split hopkinson pressure bars dear all, i was wondering whether anyone here knows any companies or institutions which can supply the complete split hopkinson pressure bars apparatus.
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