Application of X-ray Diffraction for Residual Stress Analysis in Truncated Cones Made by Incremental Forming

Abstract

The final accuracy of the parts formed using single point incremental forming greatly depends on the mechanical properties of the material to be formed and the residual stress formation. In this paper, an X-ray diffraction technique was used to study the distribution of the residual stress along the generating line of the conical drawpiece. A DC04 steel sheet with a thickness of 0.8 mm was used as a test material. The basic mechanical properties of the DC04 sheet metal were determined in the uniaxial tensile test according to the EN ISO 6892-1:2016. It was found that the maximum amount of the residual stress existed in a point located in the midway between a base and a truncation of the drawpiece. In the outer surface of the drawpiece, the orange peel defect associated with a rough surface appearance after SPIF a drawpiece, was observed. In contrast, the inner surface of component was characterized by linear grooves associated with the interaction of tool tip with the sheet surface. This defect is mainly influenced by vertical step size.

Numerical and Experimental Assessment of the Effect of Residual Stresses on the Fatigue Strength of an Aircraft Blade

“…Ong's model (1993): Concerning the material data necessary for the determination of the Ramberg-Osgood curve [14,16,31], there are three methods of their approximation. The first method was developed by Manson and published in 1964.…”

“…where: Since the numerical strength analysis of a vibrating blade in the resonance state with an amplitude of 1.8 mm was performed based on a linear-elastic model, it is necessary to use a model taking into account the cyclic hardening (from the Ramberg-Osgood Equation ( 2)), i.e., cyclic strength coefficient (K') and cyclic strain hardening exponent (n'). The Manson's, Fatemi's, and Xianxin's models were selected for the analysis [14][15][16]31]. Some models depend on the fatigue model of the material.…”

“…Knowledge of the stress state during the service as well as in the static (unloaded) state, in which the presence of the residual stresses is a result of earlier surface treatment. There are several methods for determining the value of the residual stresses, one of the most accurate and the most sensitive is X-ray diffraction [11][12][13][14]. Knowledge of the residual stresses can be included in numerical calculations to obtain results closer to the actual fatigue life results [13][14][15][16].…”

“…There are several methods for determining the value of the residual stresses, one of the most accurate and the most sensitive is X-ray diffraction [11][12][13][14]. Knowledge of the residual stresses can be included in numerical calculations to obtain results closer to the actual fatigue life results [13][14][15][16]. Such recognition of the topic may allow increasing the safety of air transport.…”

Numerical and Experimental Assessment of the Effect of Residual Stresses on the Fatigue Strength of an Aircraft Blade

“…Knowledge of the stress state during the service as well as in the static (unloaded) state, in which the presence of the residual stresses is a result of earlier surface treatment. There are several methods for determining the value of the residual stresses, one of the most accurate and the most sensitive is X-ray diffraction [11][12][13][14]. Knowledge of the residual stresses can be included in numerical calculations to get closer to the actual fatigue life results [13][14][15][16].…”