Split hopkinson pressure bar graphical analysis tool file. Is there a place i can get raw data for the split hopkinson pressure bar to. This week a brief introduction to the basics of this technique is covered. Deformation behavior of artificial rock in the split. 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. Split hopkinson pressure bar shpb apparatus along with digital storage oscilloscope lds sigma 100 and high frequency strain amplifiers fylde feh359ta. A note on data processing in the split hopkinson pressure bar tests netic energy in shpb test. A split hopkinson bar apparatus, also known as kolsky bar that is capable of conducting compressive strain rate testing in the approximate ranges from 50 to 104 in. When the striker bar impacts the copper disk, a nondispersive ramp pulse propagates in the incident bar and produces a. Fe modelling of a confined split hopkinson pressure bar shpb test on dry quartz sand was carried out using lsdyna in order to assess whether material model 5 could replicate experimental results, which would enable a more detailed investigation of the stress state in shpb specimen. The hopkinson bar is used to impose a dynamic load on a material specimen akin to that which the material will experience in dynamic situations like vehicle crashes or other highenergy events. The wave information along with the experimental setup properties are embedded in these les. The splithopkinson pressure bar shpb technique complements the laser based high rate testing by providing a method for deformation at lower rates 102104 s.
Split hopkinson pressure bar for soft materials 141 figure 21. Pdf a split hopkinson pressure bar apparatus, also known as kolsky. Split hopkinson pressure bar testing of unsaturated sand. John hopkinson, in 1872, studiedfor the first timethe behavior of iron wires by performing stress wave experiments. In this study, the strains of artificial rock were analyzed in order to estimate the deformation behavior of rocklike materials in the shpb test. John hopkinson investigated the propagation of stress waves in the iron wire in 1872, and his son, bertram hopkinson, invented a pressure bar to obtain the pressuretime curve with the dynamic load exerted by detonation hopkinson, 1914. The system can be used for experiments with test durations of up to 500.
A new split hopkinson tensile bar design sciencedirect. Unlike the lbhrt setup, the shpb can be used for tensile and torsion testing as well as compression. Pdf split hopkinson bar techniques for characterizing soft. Quasistatic tests on the same kinds of specimens were performed using a standard materials testing machine. 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. Hopkinson pressure bar shpb is widely used for investigating the dynamic behavio r of various materials. Pdf split hopkinson bar techniques for characterizing. The split hopkinson pressure bar shpb testing technique has been used to derive the constitutive equations of engineering materials at high strain rate using the reflected and transmitted waves measured from the input and output bars. However, as the strain gage data has discrete point, there will likely be a small di erence. This technique modifies the conventional split hopkinson bar apparatus by placing a thin copper disk on the impact surface of the incident bar.
Gasgunc file defines constants, the gasgunmain file initializes the. It details some of the specialized shpb techniques that facilitate testing soft materials. Naik and others published compressive split hopkinson pressure bar apparatus. Later, in 1949 herbert kolsky refined hopkinson s technique by using two hopkinson bars in series, now known as the split hopkinson bar, to measure stress and strain, incorporating advancements in the cathode ray oscilloscope in conjunction with.
Split hopkinsonson bar test appartus advance instrument inc. Design of a split hopkinson pressure bar research activities. Experimental study on split hopkinson pressure bar pulse. Using split hopkinson pressure bars to perform large strain compression tests on polyurea at low, intermediate and high strain rates. The effect of specimen geometry length to diameter ratio is investigated. A split hopkinson bar is used to dynamically determine material constants, for example youngs modulus or mechanical stress. A split hopkinson pressure bar technique to determine.
Dogbone specimens introduction the split hopkinson pressure bar schematic shown in fig. Splithopkinson pressure bar testing of soft materials. Stress equilibrium in the split hopkinson pressure bar test. In this work, in a form of a senior design project, the. Subject matter of this book is split hopkinson pressure bar or kolskey bar, an instrument for the dynamic characterization of materials. Split hopkiso pressure bar impulse experimetal pawel. Robust models that capture the materials response at different strain rates are important. Once the upload is complete, the pages of your document will be shown as thumbnails. Limiting conditions for compression testing of flat specimens in the.
This paper presents a split hopkinson pressure bar technique to obtain compressive stressstrain data for rock materials. The split hopkinson pressure bar experimental technique has been implemented to evaluate the high rate squeeze flow behavior of a concentrated shear thickening fluid stf. Uploaded files are deleted within 1 hour from our servers. Written in matlab r, the code can be freely distributed. The high strain rate characterization of materials is usually performed using the split hopkinson pressure bar within the strain rate range 1000 s1. A brief description of each of the apparatus members is given below according to their assigned numbers. The splithopkinson pressure bar, named after bertram hopkinson, sometimes also called a. The specimen is sandwiched between the transmission and incident bar. Development of a split hopkinson tension bar for testing stressstrain response of particulate composites under high rates of loading anthony taylor owens master of science, august 4, 2007 b. Using the split hopkinson pressure bar to validate. A directtension split hopkinson bar for high strainrate. Split hopkinson pressure bar shpb experiment input bar specimen output bar two force measurements ain time h r 0,t ain hh0h,ttime ll inin,t2,t ain time h r t h l t l st l in 2l st c.
As in the method devised by hopkinson, the pressure is applied normally to one end of a cylindrical steel bar, producing a stress pulse which gives rise to radial and longitudinal displacements in the bar. Currently coding a wave separation script for the split hopkinson pressure bar. What links here related changes upload file special pages permanent link page. Development of a tensile split hopkinson pressure bar testing facility. John hopkinson investigated the propagation of stress waves in the iron wire in 1872, and his son, bertram hopkinson, invented a pressure bar to obtain the pressure time curve with the dynamic load exerted by detonation hopkinson, 1914. Unlike quasistatic testing machines a splithopkinson bar enables material properties to be determined in dynamic conditions. The split hopkinson pressure bar shpb technique is analyzed during the initial stages of loading by means of axisymmetric finite element simulations of d. High amplitude, splithopkinson pressure bar shpb laboratory tests were conducted on compacted specimens of 5080 silica sand to evaluate the influence of saturation on compressionalstress wave velocity, stress transmission, and attenuation. However, the measurements were not accurate because of the limitation of the measurement technique. By kevin young a thesis submitted to the faculty of graduate studies through the department of mechanical, automotive and materials engineering in partial fulfillment of the requirements for the degree of master of applied science at the university of windsor. Finite elements method in split hopkinson pressure bar. Afterward, click on the save button on the right and confirm. Hopkinson bar techniques for the intermediate strain rate.
Manufacturing of the split hopkinson pressure bar the split hopkinson pressure bar is designed and built as shown in figure 2. The method involving the use of a splithopkinson bar enjoys increasing popularity in many applications thanks to ever more powerful test and measurement. 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. The mechanical properties of materials change depending upon the strain rate that they are subject to. This article addresses the specialized aspects required to accurately quantify the behavior of soft materials, including polymers and polymeric composites, using the split hopkinson pressure bar shpb. In this apparatus the specimen is loaded by a tensile wave that is generated by the release of a stored load in a section of the input bar. Example 8 hopkinson bar summary precise data for high strain rate materials is necessary to enable the accurate modeling of highspeed impacts. Modelling splithopkinson pressure bar tests on quartz sand. 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.
Pdf development of a tensile split hopkinson pressure bar. The dynamic compressive behavior of concrete is investigated using a. Split hopkinson pressure bar shpb is an apparatus that is used to study materials behavior under high speed deformation, where strain rate is very high. Later, in 1949 herbert kolsky refined hopkinsons technique by using two hopkinson bars in series, now known as the splithopkinson bar, to measure stress and strain, incorporating advancements in the cathode ray oscilloscope in conjunction with. Definition of the requirements for metals and advanced material am, composite 3. Characterization of three himalayan rocks using a split. The hopkinson bar is used to impose a dynamic load on a material specimen akin to that.
The split hopkinson pressure bar is a device used for characterizing material properties submitted to dynamic loading, producing high stress and strain waves. Composite materials shawn lang a thesis submitted in. Split hopkinson pressure bar test engineering breakdown. The preliminary ideas behind hopkinson pressure bar were first originated in 1872 by john hopkinson 1. This dynamic testing method of impacting a long bar and studying the stress waves produced in the bar was pioneered by bertram hopkinson early in the 20th century. Splithopkinson bar testing is a tried and tested method in materials testing. A note on data processing in the split hopkinson pressure bar tests netic energy in shpb test, davies and hunter recom mended an optimal length. If you have an engineering background, it is likely that you have come across one of the most famous testing methods. Split hopkinson pressure bar technique has been extensively used to. Split hopkinson pressure bar testing the split hopkinson pressure bar shpb technique complements the laser based high rate testing by providing a method for deformation at lower rates 102104 s. Quasistatic material tests in tension or compression at elevated temperatures are usually performed in uniaxial testing machines in combination with an oven. The axial strain measured directly from the strain gage and obtained from the process analysis of threewave method were compared. Each product is the most popular one at that price level.
One of the experimental techniques for characterising materials under the effect of high strain rates is the split hopkinson pressure bar shpb test. Design of inserts for splithopkinson pressure bar testing. Hopkinson bar technique v 0 striker split hopkinson pressure bar shpb experiment input bar specimen output bar two force measurements ain time h r 0,t ain hh0h,ttime ll inin,t2,t ain time h r t h l t l st l in 2l st c. This apparatus consists of four long pressure bars, i. In these systems, a stress pulse is generated through various means, e. All files are transferred over a secure encrypted connection s to maximize the security of your files.
Dynamic rock tests using split hopkinson kolsky bar system. Construction of data acquisitionprocessing system for. The shpb in our lab is a compression testing rig, though plans are being made for a. Split hopkinson pressure bar graphical analysis tool. Youngs modulus is a material constant that is a measure for how much a component is deformed when a force is applied to it. Split hopkinson bar shb works on the principle of one dimensional wave propagation. Split hopkinson bar shb methods are widely used to experimentally characterise the mechanical properties of materials undergoing rapid deformation,, and are generally classified into compression shcb, torsion shtob and tension shtb split hopkinson bars. Split hopkinson pressure bar a split hopkinson pressure bar shpb, also known as a kolsky bar, is a test apparatus used to characterize the mechanical response of. This book an exact copy of authors phd dissertation published in 2004 by university of delaware.
A schematic of the hopkinson pressure bar is illustrated in figure 1. Designing a data acquisition system for a split hopkinson. Gorharn faculty of technology, the open university, walton hall, milton keynes, mk7 64. Splithopkinson bar shb works on the principle of one dimensional wave propagation. The compressive split hopkinson pressure bar shpb technique allows the stresses on each end of the specimen to be measured individually. A split hopkinson pressure bar shpb system with a special shape striker has been suggested as the test method by the international society for rock mechanics isrm to determine the dynamic. The second technique is the recently developed wedge bar apparatus. We use the technique in combination with texture measurements and insitu tem. Composite materials shawn lang a thesis submitted in partial. May, 2014 the results were obtained using two hopkinsonbarrelated techniques. Select different page numbers in your preferred order and click on more to split 5 files or more. Using split hopkinson pressure bars to perform large. The results were obtained using two hopkinsonbarrelated techniques.
Its main components are a gas gun, a striker bar, an incident bar and a transmission bar. 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 splithopkinson pressure bar allows for dynamic deformation at high strain rates 10 310 4 s. Later, bertram hopkinson introduced a method to characterize the pressure variations with respect to time due to an impact produced by a bullet or explosive. Split hopkinson pressure bar graphical analysis tool documentation, version 1. The incident bar, transmission bar and striker bar are all made of same material and same crosssection area. Pdf design and characteristics of a split hopkinson pressure bar. Oct 09, 2015 a split hopkinson pressure bar shpb is used to test the high strain rate material properties of materials. Split hopkinson bar is an inexpensive device for performing high strainrate experiments. In this paper are analyzed and evaluated by the simulations means three major topics. To split between two pages, click on the scissors icon on the left page. A series of fem simulations of shpb test were used in designing of split hopkinson pressure bar equipment and its dedicated software, developed in impact laboratory, a facility of military technical academy. Pdf compressive split hopkinson pressure bar apparatus. Dynamic rock tests using split hopkinson kolsky bar.
Stress equilibrium in the split hopkinson pressure bar test x. A split hopkinson pressure bar shpb is used to test the high strain rate material properties of materials. Design of a split hopkinson bar apparatus for use with fiber. Using the split hopkinson pressure bar to validate material. The ring was modeled both axisymmetrically and in 3d to help ensure accuracy in results. The most widely used method to characterise materials at high strain rates is the split hopkinson pressure bar shpb. Split hopkinson bar, which can test materials at strain rates as high as 2000 s1. The most widely used method for obtaining high strain rate material data is the split hopkinson pressure bar, often called a kolsky bar. The design, construction and testing of unique operated. File retainment settings can be configured in preferences. The striker bar sits in the barrel at the gas gun chamber. Splithopkinson pressurebar tests on concrete and mortar. A directtension splithopkinsonbar apparatus is introduced. The splithopkinson pressure bar experimental technique has been implemented to evaluate the high rate squeeze flow behavior of a concentrated shear thickening fluid stf.
G, the code can be freely distributed either as an executable binary or editable matlab files. Also for dynamic compression testing with a splithopkinson pressure bar, it is common to attach an oven to the test rig for heating of the samples 10,11. Split hopkinson pressure bar shpb tests are used to characterize the soft tissue. Split hopkinson pressure bar technique download ebook. The first technique is the conventional split hopkinson pressure bar arrangement incorporating a novel coneintube striker design, which extends the practical testing range down to 100 s.
Failure was determined by defining a failure strain to start the process of element deletion. One of the main problems occurring during tests are oscillations recorded by the strain gauges which. Subsequently the data is recorded in comma separated file format and transferred to. Split hopkinson pressure bar a split hopkinson pressure bar shpb, also known as a kolsky bar, is a test apparatus used to characterize the mechanical response of materials deforming at high strain rates 102 104 s1. In order to reduce and eliminate the waveform dispersion effect, two pulse shaping techniques are adopted to improve the incident wave shape. In this case, a precise measurement of the reflected and transmitted waves is important to determine a reliable stressstrain relation. During experimental investigation the pulse in the incident bar was shaped by the copper disk inserted between the striker and incident bar. Output pdfs are stored for 7 days by default, but can be stored up to 1 year premium or 1 hour. The hopkinson pressure bar was first suggested by bertram hopkinson in 1914 as a way to measure stress pulse propagation in a metal bar. A dashed line will appear to show where the splitting will take place. The presented paper is focused on the shpb impulse measurement process using experiment al and numerical methods.
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