Experimental and computational modeling of bulk residual stress for aeronautical components with distinct geometries

Zheng Zhang,Liang Li,Yinfei Yang,Jinxing Kong

doi:10.1177/1687814021994402

Abstract

To predict and minimize machining distortion in the manufacturing process, bulk residual stresses in aeronautical components with distinct geometries were investigated via experimental mechanics and numerical simulation. The residual stress state was appropriately simplified according to geometric/processing feathers and deformation patterns of the investigated parts. In each case study, an optimal experimental method was selected to reconstruct the concerned stress tensor. Thereafter, qualitative comparison and validation were performed using cross-method verification and/or numerical simulation. Additionally, the spatial resolution and distribution characteristics of the residual stress were analyzed and discussed in detail. The results revealed that thermal and mechanical nonuniformity caused by material processing is the main source of bulk residual stress in the investigated components. Furthermore, the effectiveness of the contour method on the measurement of different geometric components was verified by numerical simulation. Combining the accurate measurement of the characteristic plane and the appropriate numerical simulation of the global stress field, an engineering-oriented approach for full-field stress evaluation was proposed. This research can provide valuable engineering guidance and suggestions for stress evaluation and distortion analysis prior to manufacturing of integral structures.

Highlights

Lightweight design for modern aircraft has led to the extensive application of integrally stiffened structures.[1]
The depth profiles for residual stress measured by the X-ray diffraction (XRD) are shown for verification and comparison
The XRD results indicated that the near-surface area (0–0.5 mm) exhibited a high stress gradient due to laser peening

Summary

Introduction

Lightweight design for modern aircraft has led to the extensive application of integrally stiffened structures.[1]. Distortion analysis requires adequate stress data for distinct crosssectional planes, which makes the CM ideal for measurement.[21] In an irregular beam with variable cross-sections renders measurement difficult for other common techniques, but the CM still demonstrates high spatial resolution for 2D stress maps of an arbitrary slice along the axis.[22] slitting can be applied to measure bulk stress in a simplegeometry beam with multiple cutting slices, but 2D stress maps need postprocessing to align the 1D curves.[23] neutron diffraction (ND) allows nondestructive determination; it can be used to validate CM results at the same measurement position.[21] Depending on different engineering materials, neutrons have limited penetration depth for detection.[24] Perhaps biggest limitation is that the neutron source is expensive and relatively difficult to obtain for common engineering purposes. Internal stress states can be detected using high-energy synchrotron diffraction, but with a zy

J stress σy yx Uniaxial stress σx Beam

Results and discussion

Conclusions