Effect of cooling method on small diameter blind-hole drilling of new β-type dental Ti-Zr-Nb alloy

2020 ◽  
Vol 59 ◽  
pp. 421-431
Author(s):  
Bo Chen ◽  
Feixiang Xiong ◽  
Hongqun Tang ◽  
Liang He ◽  
Shanshan Hu
Keyword(s):  
Small Diameter ◽  
Hole Drilling ◽  
Blind Hole ◽  
Cooling Method

Effect of plasticity at out-of-plane electronic speckle pattern interferometry diagnostics of axisymmetric stresses by the hole-drilling method

2017 ◽  
Vol 53 (1) ◽  
pp. 3-14 ◽  
Author(s):  
Alexander L Popov ◽  
Sergei E Alexandrov ◽  
Victor M Kozintsev ◽  
Alexander L Levitin ◽  
Dmitri A Chelyubeev
Keyword(s):  
Plastic Material ◽  
Speckle Pattern ◽  
Finite Thickness ◽  
Experimental Studies ◽  
Median Plane ◽  
Element Model ◽  
Electronic Speckle Pattern Interferometry ◽  
Hole Drilling ◽  
Disk Model ◽  
Blind Hole

Theoretical, calculated, and experimental results of studies on the registration of the accounting effect of plasticity in the diagnosis of axisymmetric stresses by the hole method and speckle-interferometric detection of the field of normal displacements in its vicinity are presented. Theoretical and computational studies were carried out on a disk model of finite thickness from an ideally elastic–plastic material. The theoretical model considers the formation of elastoplastic deformations in the vicinity of the through hole; the calculated finite element model considers in the vicinity of both through and blind holes of different depths. It was noted that at the blind hole, the most informative are the movements of the axisymmetric bend caused by the violation by the blind hole of symmetry of the disk with respect to its median plane. At the same time, an approximate analytical method has been developed to calculate the stresses that cause only elastic deformations. Experimental studies were carried out on a series of samples in the form of steel disks with axisymmetric stresses near the yield point. These stresses were induced by the hot fit of grinded rings from hardened high-strength steel onto disks made of steel with a low yield strength. Examples are given which show that the stress values determined from normal displacements in the vicinity of the probe holes from the calculated–theoretical and experimental are similar.

EXPERIMENTALLY VALIDATED SIMULATIONS OF BLIND HOLE DRILLING IN 3D WOVEN CARBON/EPOXY COMPOSITE WITH PROCESSING-INDUCED RESIDUAL STRESSES

2021 ◽  
Author(s):  
ARTURO LEOS ◽  
KOSTIANTYN VASYLEVSKYI ◽  
IGOR TSUKROV ◽  
TODD GROSS ◽  
BORYS DRACH
Keyword(s):  
Residual Stresses ◽  
Epoxy Matrix ◽  
Mechanical Performance ◽  
Matrix Cracking ◽  
Woven Composites ◽  
Hole Drilling ◽  
Blind Hole ◽  
Matrix Cracks ◽  
Numerical Predictions ◽  
3D Woven Composites

Manufacturing-induced residual stresses in carbon/epoxy 3D woven composites arise during cooling after curing due to a large difference in the coefficients of thermal expansion between the carbon fibers and the epoxy matrix. The magnitudes of these stresses appear to be higher in composites with high throughthickness reinforcement and in some cases are sufficient to lead to matrix cracking. This paper presents a numerical approach to simulation of development of manufacturing-induced residual stresses in an orthogonal 3D woven composite unit cell using finite element analysis. The proposed mesoscale modeling combines viscoelastic stress relaxation of the epoxy matrix and realistic reinforcement geometry (based on microtomography and fabric mechanics simulations) and includes imaginginformed interfacial (tow/matrix) cracks. Sensitivity of the numerical predictions to reinforcement geometry and presence of defects is discussed. To validate the predictions, blind hole drilling is simulated, and the predicted resulting surface displacements are compared to the experimentally measured values. The validated model provides an insight into the volumetric distribution of residual stresses in 3D woven composites. The presented approach can be used for studies of residual stress effects on mechanical performance of composites and strategies directed at their mitigation.

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]

Multi-channel laser system with phase locking by holographic gain gratings and small diameter deep hole drilling

2007 ◽  
Author(s):  
Alexander V. Fedin ◽  
Andrey V. Gavrilov ◽  
Sergey N. Smetanin ◽  
Sergey A. Solokhin
Keyword(s):  
Phase Locking ◽  
Laser System ◽  
Small Diameter ◽  
Hole Drilling ◽  
Deep Hole ◽  
Deep Hole Drilling
Sign in / Sign up

Export Citation Format

Share Document