Study of Residual Stress Distribution by a Combined Method of Moire´ Interferometry and Incremental Hole Drilling, Part I: Theory

1998 ◽  
Vol 65 (4) ◽  
pp. 837-843 ◽  
Author(s):  
Zhu Wu ◽  
Jian Lu ◽  
Bongtae Han
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Plane Surface ◽  
Moiré Interferometry ◽  
Hole Drilling ◽  
Moire Interferometry ◽  
Hole Drilling Method ◽  
Surface Displacements ◽  
Incremental Hole Drilling ◽  
Drilling Method

A new method combining Moire´ interferometry and the incremental hole-drilling method is developed to determine both uniform and nonuniform residual stress distribution in depth. The study is reported in two parts. In this first part, the theoretical development of the moire´ interferometry hole-drilling method is presented. The relationship between the in-plane surface displacements produced by introducing a blind hole and the corresponding residual stresses is established by employing the existing theoretical solution containing a set of undetermined coefficients. The coefficients are calibrated by the three-dimensional finite element method and they are processed nondimensionally for general use. The whole field in-plane surface displacements data Ux and Uy produced by the relaxation of residual stresses are obtained from moire´ interferometry after each increment of hole drilling. The high signal-to-noise ratio provided by moire´ interferometry allows accurate determination of fringe orders near the hole boundary which is essential for enhancing fidelity of residual stress determination. The experimental procedure to determine the signs of residual stresses is described and the accuracy of the method is also discussed.

Study of Surface Residual Stress by Three-Dimensional Displacement Data at a Single Point in Hole Drilling Method

1999 ◽  
Vol 122 (2) ◽  
pp. 215-220 ◽  
Author(s):  
Z. Wu ◽  
J. Lu
Keyword(s):  
Residual Stress ◽  
Single Point ◽  
Accurate Determination ◽  
Three Dimensional ◽  
Moiré Interferometry ◽  
Hole Drilling ◽  
Moire Interferometry ◽  
Blind Hole ◽  
Hole Drilling Method ◽  
Drilling Method

A method combining moire´ interferometry, Twyman–Green interferometry, and blind hole drilling method is proposed for simple and accurate determination of residual stress. The relationship between the three-dimensional surface displacements produced by introducing a blind hole and the corresponding residual stress is established by employing the Fourier expansion solution containing a set of undetermined coefficients. The coefficients are calibrated by 3D finite element method. The surface in-plane displacements Ux,Uy, and the out-of-plane displacement Uz produced by the relaxation of residual stress are measured by moire´ interferometry and Twyman–Green interferometry, respectively, after the hole-drilling procedure. The complete three-dimensional displacement data at any single point around the hole can be used for residual stress determination. The accuracy of the method is analyzed and the experimental procedure is described to determine the sign of residual stresses. As an implementation of the method, a shot peening residual stress problem is studied. [S0094-4289(00)00802-1]

Experimental Measurement of Residual Stress on Thermal Spray Coatings with Moire Interferometry and Hole-Drilling Method

2015 ◽  
Vol 782 ◽  
pp. 335-340
Author(s):  
Jian Guo Zhu ◽  
Bao Ge Zhang
Keyword(s):  
Residual Stress ◽  
Surface Displacement ◽  
Moiré Interferometry ◽  
Hole Drilling ◽  
Moire Interferometry ◽  
Spray Coatings ◽  
Hole Drilling Method ◽  
Drilling Method ◽  
Sprayed Coating ◽  
Thermally Sprayed

Residual stress is one of the important factors in thermally sprayed deposits which affects both processing and performances. In the present study, the hole-drilling method and moire interferometry were used to determine the residual stress of thermally sprayed coatings to overcome certain limitations of the strain rosette version of hole drilling. The methodology was established based on the elastic theory and finite element method. The residual displacement was measured by moire interferometry and the residual stress of the thermally sprayed coating was calculated. The results have demonstrated that moire interferometry for surface displacement caused by hole-drilling is high sensitive, reliable and stable.

Influence of Residual Stresses on the Damage of Composite Laminates under Tensile Loading

2015 ◽  
Vol 784 ◽  
pp. 361-368
Author(s):  
Zhong Meng Wen ◽  
Xiao Lu Gong
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Composite Laminates ◽  
Tensile Loading ◽  
Hole Drilling ◽  
Acoustic Emission Technique ◽  
Hole Drilling Method ◽  
Incremental Hole Drilling ◽  
Drilling Method

This work investigates the effect of residual stresses on the damage of composite laminate. The incremental hole-drilling method is applied to determine residual stresses in composite laminates [02/θ2]s and then acoustic emission technique is used for the identification of damage appearance during the tensile testing. The samples with different residual stress distribution are prepared through curing and post curing in order to study the role of residual stress on the damage of composite laminates. Besides the experimental method, the theoretical approach is applied to illustrate the role of residual stress on the damage of composite laminates.

Study of Residual Stress Distribution by a Combined Method of Moire´ Interferometry and Incremental Hole Drilling, Part II: Implementation

1998 ◽  
Vol 65 (4) ◽  
pp. 844-850 ◽  
Author(s):  
Zhu Wu ◽  
Jian Lu ◽  
Bongtae Han
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Moiré Interferometry ◽  
Hole Drilling ◽  
Moire Interferometry ◽  
Combined Method ◽  
Incremental Hole Drilling ◽  
Experimental Apparatus ◽  
Fringe Patterns ◽  
Incremental Step

An experiment is devised to implement the combined method of moire´ interferometry and incremental hole drilling which was proposed in the companion paper. A unique experimental apparatus is designed to combine an optical set up for moire´ interferometry with an incremental hole-drilling device. The apparatus maintains a constant relative position of a drilling device to the specimen while alternating moire´ interferometry measurements with incremental hole drilling. The drill-bit can reenter the hole for each incremental step. The incremental hole-drilling device produces a precise control of incremental hole depth with an accuracy of 0.1 μm. The method is utilized to measure the residual stresses of two shot-peened materials: AS10U3NG aluminum alloy and the ten percent SiCp reinforced aluminum composite-F3K10S Duralcan with a T6 heat treatment. Moire´ fringe patterns with excellent contrast and high signal-to-noise ratio are obtained, which allows the extraction displacement data at the points very close to a hole boundary. In the experiment, a total number of ten steps of incremental hole drilling with an identical increment of 0.1 mm are performed. The fringe patterns of Ux and Uy displacement fields are recorded after each increment and the displacement data at the points of r = 1.2r0 are extracted consequently. They are used to determine the nonuniform residual stress distributions of surface and subsurface layers of shot-peened materials. The results indicate that the medium level of approximately equibiaxial compressive residual stresses exist within a 0.3 mm layer.

scholarly journals The Effect of Fiber Waviness on the Residual Stress State and Its Prediction by the Hole Drilling Method in Fiber Metal Laminates: A Global-Local Finite Element Analysis

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 156
Author(s):  
Steffen Tinkloh ◽  
Tao Wu ◽  
Thomas Tröster ◽  
Thomas Niendorf
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Residual Stresses ◽  
Global Model ◽  
Hole Drilling ◽  
Fiber Waviness ◽  
Hole Drilling Method ◽  
Residual Stress State ◽  
Incremental Hole Drilling ◽  
Drilling Method

In this paper, fiber waviness, as one of the most frequently occurring defects in fiber reinforced composites, is numerically investigated with regard to the formation of residual stresses in fiber metal laminates. Furthermore, the prediction of the residual stress state in the thickness direction by means of the simulated hole drilling method is studied. To this regard, a global-local finite element analysis based on the submodel technique is presented. The submodel technique essentially consists of two governing steps: In the first step, a global model is first utilized to calculate and analyze the residual stress distribution and deformation in the intrinsically joined hybrid structure. Effective cure-dependent thermo–elastic properties predicted by a numerical homogenization procedure were used to simulate the curing-process and analyze the residual stresses state. However, the dimension of the intrinsically manufactured hybrid plate is large compared to the diameter of the drilled hole (2 mm), so that a local model is necessary, which provides only a geometric partial portion of the global model. The local model takes the global stress state into account and is subsequently used to simulate the incremental hole drilling method with a refined mesh discretization. The production-related fiber waviness is modeled by an element-wise orientation approximating a sinus function. In order to validate the global-local modeling approach, a comparison between numerical results and experimental data from literature is presented. The comparison between global residual stress state (global model) and the simulated hole drilling method (local model) is used to assess the applicability and reliability of the hole drilling method in case of fiber waviness. It is found that an in-plane fiber waviness leads to a rather low variance of residual stresses over thickness. In case of an out-of-plane fiber waviness, oscillating residual stress fields occur over the entire thickness along the fiber direction. Moreover, the current limits of the incremental hole drilling method could be pointed out by the presented investigations. It is seen that the simulated results of the incremental hole drilling method are sensitive to waviness, even if the amplitude-wavelength-ratio is small. Without further adjustment of the calibration coefficients the oscillating stress and strain fields lead, in particular fiber waviness in thickness direction, to unreliable predictions. For the experimental application it can be concluded that the specimens have to be carefully examined with regard to fiber waviness.

Sign in / Sign up

Export Citation Format

Share Document