Development of Single Specimen Creep Testing Machine

Abstract

The work intends to provide single specimen creep testing machine for laboratory use. This will enhance selection of appropriate materials for national building/advancement. The method employed involves selection of material, design of components of machine, production of components and assembling of the components. The machine comprises of a lever arm, supported with pivot pin and rest pin on the columns. The effort portion of the lever arm is fixed with load hanger while the load (test) portion is fixed with dial gauge, the ends of specimen were fixed in fixture devices on lever arm and base table at a distance of 90 mm. Development of the machine was based on the application of bending moment (simple supported beam) and equilibrium theory to calculate the forces acting on the specimen and components of the machine which is obtained as F=(1.596 + 5.99m)g Newton. Using solder as specimen, tests were carried out with the machine at room temperature under different loads, concept of strain were obtained. Three stages of creep were achieve, creep constants of solder (m and B) were obtained experimentally as 6.25 x 10-3 and 4.0 x 10-4 respectively. The experiment indicates that at a constant stress 31.13 MPa, the creep rate was obtained as 2.1 x 10-3 /min while at 38.60 Mpa, the creep rate was obtained as 6.2 x 10-3 /min. The results indicate that the creep rate increases at higher stress, the creep working hypothesis were confirmed.