Tensile Test

13.03.2020 Seyid Ali KOLU 010170419 Tensile Test Introduction In this test the load is applied along only one axis, and the rate of loading is constant. This test is done on a universal mechanical testing machine which is typically screw-driven or hydraulically powered. In some cases the machine may be computer controlled. The primary data generated are load vs. elongation which are to be converted into stress vs. strain data. In modern tensile testers, load is measured using a load cell, in older or simpler testing machines, a purely mechanical or hydraulical device may be employed for measuring the load. Strain can be measured from the displacement of the crosshead or directly from the specimen. Typical devices for measuring strain are mechanical dial indicators, electrically-resistive strain gages attached to the specimen, or extensometers that employ either an optical device, a strain gage or an inductive or capacitive transducer. Strain transducers have the advantage that they measure only the displacement in the gage length of the specimen. This eliminates error due to the deformation in the ends of the specimen, slack in the load train, and the stiffness of the testing machine. There are different types of specimen depending on the type of the grips and on the form of the available material (sheet, rod, etc.). Generally all specimens have two main parts, the gage section and the ends. The dimensions of the specimens are standardized (TS, DIN, ASTM etc.) A good surface finish is required so that surface flaws do not provide stress concentrations to cause premature failure. EXPERIMENTAL PROCEDURE Tensile test is applying force in axial direction to materials. Steel is used as reinforcement in reinforced concrete and as main construction element in steel constructions. Tensile strength of concrete is very low when compared to steel therefore tensile strength of steel is very important for calculations. When tensile force in axial direction is applied to a material its length increases as its area of cross section decreases. Eventually fracture occurs. RESULTS Yield Stress = 153,6 kN / 20 mm =7.68 Ultimate Stress = !92,2 kN / 20 mm = 9,61 Fracture Stress = 182,8 kN / 20 mm = 9,14 Reduction in Cross Section = Ductility (Ek) = (L’k-Lk/100)*100 (123.6-100/100)*100 = 23.6 - Striction Strain = 10cm/20mm = 5 - Uniform Strain =