In structures, which are free from RESIDUAL STRESSes, the STRESS intensity factor can be evaluated using the displacement extrapolation techniques. These numerical values are often in good agreement with the energy based calculations. In practice, the energy-based J-Integral is used for many structures as the appropriate fracture parameter or for the indirect calculation of the STRESS intensity factor. If the J-integral is to be evaluated in presence of RESIDUAL STRESSes based on its original expression, the obtained integral will not be path independent. In this paper, a modified form of the J-Integral is used and its path independency is verified. The J-integral is evaluated for two different geometries and the effects of various RESIDUAL plus applied STRESSes are investigated.

Inelastic solution of an axisymmetric boundary value problem is obtained from elastic solution using variable material properties method. The distribution of material properties, which are considered as field parameter is obtained as a part of the solution. This method is applied to process of cold worked fastener holes. The RESIDUAL STRESS field induced by the process is determined. The actual material behavior in loading and unloading is utilized, while different hardening models, isotropic and kinematic hardening, are also used. Results are shown to be in good agreement with published results. The process of recoiled work is also studied. It is shown that a recold worked fastener hole may have a more useful RESIDUAL STRESS pattern.

STRESS and RESIDUAL STRESS are the main problems in the operating materials. They are the principal causes of material failure and may affect life time of component. However measurement or their predictions are typically difficult. Two common non-destructive methods, X-ray diffraction and ultrasound are not reliable methods for subsurface RESIDUAL STRESS measurements, and destructive holedrilling method is not absolutely precise and safe. In this study, the PEC method was applied to the qualitative and quantitative measurements of STRESS in aluminum alloy specimens. PEC is a high performance non-destructive testing technique but its application in STRESS and RESIDUAL measurement is unknown. In this study a qualitative and quantitative approach for measuring RESIDUAL STRESS by PEC technique was developed. Results indicated that pulsed eddy current responses are sensitive to STRESS and revealed that PEC method is capable of RESIDUAL STRESS measurements.

RESIDUAL STRESS Measurement has gained interests among researchers for many years due to its great influence on the structural integrity. Slitting Method is one of the destructive techniques that relies on the introduction of an increasing cut to a part containing RESIDUAL STRESSes. Similar to all other mechanical strain relief techniques, slitting also suffers from its shortcomings during the measurement procedure. In the present research, slitting method was simulated using finite element analysis. Furthermore, the experimental procedure of the slitting method was carried out. The quenching was employed to induce RESIDUAL STRESSes within a sample made of 316L steel. A strain gauge was attached in the correct location and the RESIDUAL STRESSes were measured using the compliance coefficients. The experimentally measured STRESSes were then compared with those predicted using finite element analysis. A very good correlation was observed.

In this paper, Digital Image Correlation method (DIC) and the introduction of a new Nondestructive method for measuring RESIDUAL STRESSes in mechanical parts has been investigated. In this regard, with the purpose of scientific proof of the proposed new method, a review of the related work to the presented idea and its details has been discussed. Initially, the principles of digital image correlation method and the methods used to calculate correlation coefficients are presented. In order to evaluate the accuracy of digital image correlation method outputs, by construction the required equipment and doing experimental tests, comparing the output results of the digital image correlation method and the simulation results of finite element are discussed. In the following, the proposed method for measuring the RESIDUAL STRESSes in mechanical parts by applying loads in the elastic and Nondestructive area has been discussed. The proposed relationship, which is based on Hooke's law, is capable of evaluating and calculating RESIDUAL STRESSes in a Nondestructive, full-screen, and high-precision manner. For scientific proof, the steel samples are welded by the SMAW process and the amount of RESIDUAL STRESSes found in the parts has been calculated.

This paper presents the coating thickness effect on the STRESS distribution of a coated cylinder head. A typical thermal barrier coating was applied on a diesel engine cylinder head. Thus, the RESIDUAL STRESS which occurred during the plasma thermal spraying was also considered. The coating system consisted of two layers; a metallic bond coat and a ceramic top coat. The bond coat thickness is considered as 50 to 250 µm and the top coat thickness was considered as 200 to 800 µm. The STRESS distribution was found by the finite element analysis using the ABAQUS software. Then, STRESS distributions were compared for various coating thicknesses. Finally, optimized values for each layer are suggested.