Dynamic Buckling of Steel Alloy (drilling shaft) Under Different Conditions of Work Using Shot and Laser Peening Surface Treatments

Abstract

The calculations of buckling loads are of great importance for industry. This thesis presents the description of experiments carried out on two specimen (columns) types of buckling namely, long and intermediate columns. These specimens are made from 304 stainless steel alloy which is used in many industrial applications.32 specimens subjected to an increasing compressive load without shot peening (WSP) and with shot peening (SP). The main objectives of the research to study the loads of columns without corrosion in oil field as well as study and evaluate the effect of corrosion. These investigated through studying the buckling behavior of solid column with fixed-pinned condition and evaluation the effect of corrosion time on the dynamic buckling behavior. The study used Euler Formula foe long columns, Johnson Formula for intermediate and short columns and Perry-Robertson as well for the three columns types. In order to assess the critical failure an electrical Laser alarm was designed and built within the buckling test rig. At the instance when the specimen buckle reach to 1% of sample length, the electrical circuit operates immediately and the test rig stops. The buckling deflection is measured by digital dial gauge which is fixed on the side of test rig in contact within 0.7 of specimen length. The results were obtained experimentally without any heat treatment for both cases, (without the use of shot peening (WSP) and when using the shot Peening (SP)). The results of practical experiments were compared with the theoretical formulas of Perry-Robertson, Euler and Johnson where these theories showed an overestimate of the critical flexural loads required the introduction of safety factor 1.3 and 3, respectively, to bring the experimental and theoretical results into good agreement. The best improvement was achieved in the intermediate columns with a diameter of 10 mm and a thinness ratio of 112. Also Noticed the maximum reduction in overturning load was (28%) and (19.6%) for the long and medium columns respectivelycompared to the columns that have been eroded as a result of burial in the soil. Of the desired importance, the study found the possibility of extending the life of the304 stainlesssteelalloy used, which facilitates the operations inside the oil well and extends the life of the equipment used and also in a way that contributes to the economics of the various oil operations.