On the Sensing and Calibration of Residual Stresses Measurements in the Incremental Hole-Drilling Method.

Mohamed Ammar,Kai Lai,Bijan Shirinzadeh,Weichen Wei

doi:10.3390/s21227447

Mohamed Ammar, Kai Lai + Show 2 more

Open Access

https://doi.org/10.3390/s21227447

Copy DOI

Abstract

The current study presents three calibration approaches for the hole-drilling method (HDM). A total of 72 finite element models and 144 simulations were established to calibrate the measurements of the strain sensors. The first approach assumed the stresses acted on the boundaries of the drilled hole and thus analyzed the surrounding displacements field. The second analysis considered the loads on the outer surfaces of the specimen while measuring the strains’ differences between the model with and without the drilled hole. The third approach was more comprehensive as it considered the mechanical and thermal effects of the drilling operations. The proposed approaches were applied to two different materials (AISI 1045 and CFRP). The steel specimens were machined using a CNC lathe while the composite laminates were manufactured using the robotic fiber placement (RFP) process. Subsequently, the residual stresses (RSs) were measured using the HDM. The obtained data were compared with X-ray diffraction measurements for validation. The results showed better estimation of the RSs when utilizing the third approach and clear underestimation of the stresses using the second approach. A divergence in RSs values between the three approaches was also detected when measuring the stresses in the internal layers of the composite laminates.

Highlights

Manufacturing and processing materials are considered the main sources of internal stresses (i.e., residual stresses (RSs)) inside structures
The incremental hole-drilling method (IHDM) was applied with the three calibration approaches to determine the stresses induced in the steel disks which were machined under the same conditions as [31]
The RSs were underestimated using all the approaches of IHDM compared with the X-ray diffraction (XRD) technique

Summary

Introduction

Manufacturing and processing materials are considered the main sources of internal stresses (i.e., residual stresses (RSs)) inside structures. The fatigue life, brittle fracture process, dimensional stability, distortion, and corrosion resistance can all be considerably impacted by RSs. In addition, RSs can be manipulated to improve material behavior under specific mechanical applications [1]. Much research has been conducted in order to measure and predict the induced RSs inside materials, as this is considered an important stage for designing the structural components and estimating their reliability [2,3,4,5]. The stresses inside the material are usually estimated in two common ways, optical methods [6,7,8,9] or using physical sensors [10,11,12]. Different experimental and numerical techniques are utilized to precisely determine the magnitude and types of the stresses, such as the hole-drilling method (HDM) [13,14], X-ray diffraction (XRD) [15], the neutron diffraction method [16], the slitting method [17], and the curvature method [18]

Methods

Results

Conclusion