The hydraulic bulge test hbt method is proposed to determine material tensile strengths. When hydraulic pressure is used, the test is not a ected by friction. Hydraulic bulge test has been done on six samples of steel sheet rak4070 with thickness. The hydraulic bulge test represents one of the basic tests to determinate not only material limit stages but also stressstrain curves for the relevant stress state. S gyce to ftos be b, cc ti g qme ieo to yen c h s t the dome hoc e to hemi 2 to be neckrog. Investigation of forming limit curves of various sheet. By analyzing the free hydraulic bulge test results, it was found that the maximum bulge heights of trip seamless steel tubes with the internal pressure boosting velocity of 0. The hydraulic bulge test is widely used in determin ing the strain hardening properties of sheet materials in biaxial tension. Derived from these approaches of material characterization using an elliptical bulge test, the potential to use the material data of the. Therefore, this research studied the formability of sheet metal by hydraulic bulge test. The mechanical parameters resulted from the bulge test in combination with the results from the tensile tests are used to determine the yield loci of the two materials. A procedure for the evaluation of flow stress of sheet.
Several hydraulic tube bulge test procedures have been proposed so far. Pdf determination of material parameters of sheet metals. A procedure for the evaluation of flow stress of sheet metal. The effect of the number of input parameters on the capability of the bbc 2008 yield criterion to predict the yield locus is also discussed in the paper. The closedform solution for the hydraulic bulge test was also derived. Then, a response value was defined as a function of the limit strains.
Determination of the biaxial yield stress using the hydraulic bulge test to determine the biaxial yield stress by means of the hydraulic bulge test, a sheet metal board is clamped between the blank holder and the stamper and is loaded with oil pressure. The available tests for the determination of flds include. Using 3d printing technology to produce the molds to reduce costs and to guide the design of sheet hydroforming process using pla polylactic acid material. Formability characterization of titanium alloy sheets.
Stelios kyriakides the bulge test is a commonly used experiment to establish the material stressstrain response at the highest possible strain levels. The bulge test is a commonly used experiment to establish the material stressstrain response at the highest possible strain levels. A bulge test can be performed using mechanical punches or the hydraulic pressure of a fluid. Determination of stressstrain relationship of tubular. The main problem of using the hydraulic bulge test for determining the stressstrain relationship is the measurement of the meridian radius r. The basic stressstrain curves measured by the hydraulic bulge test. A hydraulic bulge warm forming machine, which is used for hydraulic bulge tests with a fixed tube length, is also designed and manufactured. The bulge test is an important experimental technique to identify the properties of materials and, in particular. A thin disc is clamped around the edges and subjected to increasing fluid pressure on one side as illustrated in fig. The tensile test and the hydraulic bulge test are two methods for obtaining the material properties of tubular material. Apr 06, 20 as a requirement of the mechanical engineering undergraduate program our group was tasked with studying mcmasters existing hydraulic bulge test apparatus and improving its current state. Jp2006061944a hydrostatic bulging method, hydrostatically.
Calibration of gtn damage model parameters using hydraulic. Mj04 design of a hydraulic bulge test apparatus youtube. Pdf characterization of plastic behaviour of sheet metals. A score of less than 70% is a strong indication that gpms basic hydraulic troubleshooting workshop should be attended prior to our machinespecific hydraulic troubleshooting workshop to reap significant.
The sheet metal used in automobile industries was employed. In many cases the flow curve obtained from this experiment deviates considerably from that obtained by. Small specimen testing is a technology used to get the. Improvement of numerical modelling considering plane. Jun 02, 2014 therefore, this research studied the formability of sheet metal by hydraulic bulge test. This test is similar to the lugeontype hydrojacking test and is conducted at the end of a test. The hydraulic bulge test is widely used in determining the strain hardening properties of sheet materials in biaxial tension. Flow curves can be derived from the hydraulic bulge test for the biaxial stress state, and the higher strain values can be achieved in comparison to the tensile test without extrapolation. Pdf in sheet metal forming operations the mechanical properties of the sheet metal stressstrain curve, flow stress greatly influence metal. As the sheet bulges, the region near the dome becomes nearly spherical 1.
The specimen geometry, test device and testing procedure are three major aspects of the experiments. The displacement response is measured using an interferometric method with high resolution. The h test id the sheet hag gmoo t h accc has t out have pace be ghee e me go to this toere made on bead respec 3 e vs do ghee e blank a b is occq. Results from the hydraulic bulge test can be used both for forming limit diagrams creation and also as an important input data for numerical simulations. Determination of material strengths by hydraulic bulge test mdpi. Hydraulic bulge test with aluminum alloy sheet aa5182o. We develop a mathematical model using firstorder shear deformation theory of plates with stretching and the lubrication approximation for the newtonian fluid flow. The circular specimen was installed on the hydraulic bulge test machine, and the hydraulic system provided the pressure to form the specimens into the dome shape. The hydraulic bulge test in combination with digital image correlation dic system is the state of the art for the determination of the biaxial stressstrain curves 89 10. The systematically comparison between small punch test and hydraulic bulge test is carried out, which include specimen geometry, the test device, testing procedure, testing results interpretation. Finite element fe models of the hydraulic bulge test and uniaxial tensile test. A comparison flow stress curve of hydraulic bulge test and. It is clamped in place and inflated with hydraulic pressure.
Pdf characterization of plastic behaviour of sheet. Pdf this work covers the finite element analysis of geometric and process parameters in hydraulic bulge tests in terms of the accuracy of the. The use of shear instability criterion to predict local necking in sheet metal deformation international journal of mechanical science, vol. Membrane theory the membrane theory is commonly used to determine the. The basic idea of hbt is similar to the small punch test spt, but inspired by the manufacturing process. Pdf determination of material strengths by hydraulic bulge test. A comparative study on hydraulic bulge testing and. A comparative study on hydraulic bulge testing and analysis. On the other hand, if the flow stress curve obtained from uniaxial tensile test is used, the work piece will only be able to form about 15 millimeters before lacerating. Determination of material strengths by hydraulic bulge test.
Characterization of plastic behaviour of sheet metals by. Strain curves of sheet metals by hydraulic bulge test. In the hydraulic bulge test, a sheet metal test specimen is bulged by a hydraulic medium. Hydraulic bulge test represents an alternative method to obtain the stressstrain hardening curve for sheet metal materials. The hydraulic bulge test is used to determine stressstrain properties of sheet metal under biaxial tension. Research highligths of sheet metal testing by hydraulic. When compared to standard uniaxial tensile test it.
From hydraulic bulge test have been evaluated a yield of point re, tensile strength rm, total deformation by breaking sample, process of dependence actual stressstrain and bulging press bulging height. When compared to standard uniaxial tensile test it permits higher range of deformation, thus being possible a better material characterization. In hydraulic bulge test the biaxial stretch forming of the sheet metal is done by fluid pressure. Comparison of flow curves of aa 5457 o sheet material. In the bulge test, stress and strain can be determined up to failure of the specimen, while in the conventional uniaxial test only the uniform strain range can be utilized. Modern hydraulic systems require filtration with a beta ratio of 200 99. Hydraulic bulge testing is a material characterization method used as an alternative to tensile testing with the premise of accurately representing the material behavior to higher strain levels. Comparative study between small punch test and hydraulic. As a requirement of the mechanical engineering undergraduate program our group was tasked with studying mcmasters existing hydraulic. The cross tensile test allows both balanced and unbalanced inplane biaxial stretching 10 but an optimised cruciform specimen is required and it should fig.
Current models like yld20002d or hill48 do not consider the plane strain state, though this condition is primary cause of failure in deep drawing. Hydraulic bulge tests are preferred instead of tensile tests on account of presuming the problems can occur during the formation process of sheet material. The procedure is based on an analytical model of the bulging process and involves the measurement of only two parameters pressure acting on the surface of the. An overview of a complete hydrofracturing test is presented in fig. Pdf determination of flow stress by the hydraulic bulge test. How to do step by step conduction and convection mode of heat transfer using abaqus duration. Using this approach, the values of gtn model parameters were calculated for the bondal sandwich sheet a sandwich sheet with dc06 skin sheets and a polymeric core layer. Pdf analysis of the hydraulic bulge test with fea concerning the. Bulge test, stressstrain curve, material characterization, sheet metal forming abstract. The design process is explained in detail with focus on the challenges faced.
Test results are reported as a beta ratio of the number of particles greater than a designated size upstream of the test filter compared with the number of samesized particles downstream. In order to investigate the finite element method for tube hydroforming in a condition similar to the actual tube hydroforming, the tube material properties must be determined by hydraulic bulge test. How much do you understand this concept and in particular the hydraulic symbols. A bulge test can be performed using mechanical punches or the hydraulic pressure of a uid. Results show that sheet metal formation simulated by using the flow stress curve obtained. Specifically, the hydrodynamic bulge test relies on a pressure drop measurement across a rectangular microchannel with a deformable top wall. Provided is a hydraulic bulge method in which a formed flange width has a predetermined dimension, can be processed with little variation, can be axially pressed, and can reduce cracks generated at the flange tip. Enhancing the hydraulic bulgetest using full eld dic data m rossi, a lattanzi and d amodio faculty of engineering, universit a politecnica delle marche, via brecce bianche, 601, ancona, italy email. In this test, the spcc sheet metal was tested at 1.
Development of hydraulic bulge test to study effect of. Mechanical properties testing of sheet metal by hydraulic. The relation between stress and strain from both methods would then be compared and simulated into cubicshaped models by using finite element method. It is anticipated that an improved yield locus contour which. The quiz below should be administered to all maintenance personnel responsible for hydraulic equipment. To determine the biaxial yield stress by means of the hydraulic bulge test, a sheet metal board is clamped between the blank holder and the stamper. The equipment was designed to accommodate material strength of up to mpa with plate thickness between 1. Improvement of numerical modelling considering plane strain. A precise characterization of material behavior is necessary to identify yield criteria or hardening laws for an accurate numerical design of sheet metal forming processes. Influence of the anisotropy and the hardening on the drawability of the steel sheet in polish. The basic idea of hbt is similar to the small punch test spt, but. The basic stressstrain curves measured by the hydraulic bulge test thus.
Meridional section of a clamped sheet before time t 0 and during time t bulging be loaded by special equipment. As in hydrojacking tests, the objective is to determine the pressure at which a significant increase in transmissivity occurs reflecting fracture opening. The hydraulic bulge test was identified as the most economical solution. A major advantage of the bulge test over the more conventional uniaxial tensile test is that the stressstrain curve extends to the range of effective strain found in many forming processes. Enhancing the hydraulic bulgetest using fullfield dic.
Hydraulic bulge tests of magnesium tubes at elevated. Development of a hydraulic bulge test to determine the work. Scientifically defined, hydraulics is the branch of science that deals with the passage of liquids through pipes and paths. The bulge test is a commonly used experiment to establish the material stressstrain response at the highest possible. Using this selfdesigned testing machine, experiments of bulge tests of magnesium alloy az61 tubes at elevated temperatures are carried out. Conditions of stability loss during the test of hydraulic.
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