No abstract

No abstract

In certain applications, it is important to measure the mechanical properties of steel with high accuracy. These measurements are usually performed by destructive processes, in which the test sample is destroyed. Destructive techniques cannot detect the minuscule changes made in the mechanical properties of steel during heat treatment processes. Ultrasonic nondestructive testing is an alternative method that can be used for measuring the mechanical properties of steel more precisely. In this paper, the ultrasonic method is used for measuring the elastic properties of AISI 52100 steel samples which are heat treated at different levels. Each sample has its specific microstructure and hardness due to the heat treatment process it has gone through. The elastic properties of each sample are obtained by measuring the velocities of longitudinal and shear waves in each sample. Comparison of the results obtained from ultrasonic measurements with those available in reference tables shows that the ultrasonic technique can measure the elastic properties of AISI 52100 samples with high accuracy. The ultrasonic technique also shows that it can identify the tempered martensite embrittlement zone in AISI 52100 samples.

In the past few years, the use of carbon fibre reinforced polymer (CFRP) has increased, because of their high strength, in concrete elements such as shear walls. In this study, the behaviour of a shear wall strengthened with different layout configurations of CFRP under lateral loading was investigated. For this purpose, a model is first verified in laboratory work, then in the next step the models were analysed by increasing the number of fibre layers and the effect of fibre layers on shear wall capacity was studied. Sliding between fibres and concrete was neglected. Also the effect of increasing the concrete strength of a reinforced concrete (RC) wall on CFRP strengthening was studied. In all models, comparisons were made between the results of CFRP configurations in increasing lateral strength and also ductility. Finally, by comparing the results, the best fibre configuration was determined based on the maximum load capacity.

No abstract