Frequency Shift in Drilling due to Margin Engagement

2005 ◽  
Vol 127 (2) ◽  
pp. 271-276 ◽  
Author(s):  
D. N. Dilley ◽  
D. A. Stephenson ◽  
P. V. Bayly ◽  
A. J. Schaut
Keyword(s):  
Frequency Shift ◽  
Three Dimensional ◽  
Hole Drilling ◽  
Frequency Increase ◽  
Element Analysis ◽  
Pilot Hole ◽  
Frequency Matching ◽  
The Past ◽  
Chatter Prediction ◽  
Embedded Model

Drill chatter degrades hole roundness, hole size, and tool life. This wastes time and money in tools, scrap, and hole rework. Chatter prediction in milling and turning has shown significant benefit to industry; however, researchers have been unable to accurately predict chatter in drilling applications. In the past, the drill, including the chisel edge, was modeled as either a fixed-fixed or fixed-pinned beam (Tekinalp, O., and Ulsoy, A. G., 1989, “Modeling and Finite Element Analysis of Drill Bit Vibrations,” ASME J. Eng. Indust. 111, pp. 148–154), but more recent research (Dilley, D. N., Bayly, P. V., and Schaut, A. J., 2005, “Effects of the Chisel Edge on the Chatter Frequency in Drilling,” J. Sound Vib., 281, pp. 423–428) has shown that a fixed-embedded model using springs improves frequency matching. The effects of the drill margins on dynamics have not been studied. The fixed-fixed or fixed-pinned model will be shown to be inappropriate for modeling the effects of margin engagement, while the spring-end boundary condition can better approximate the frequency increase observed experimentally as the drill margins engage deeper into the hole. In addition, the shifted frequency is well below the frequency found from an analytical fixed-fixed or fixed-pinned beam. Evidence that the margins cause the frequency shift is seen in three-dimensional waterfall plots that show this shift for pilot hole drilling (in which the margins are engaged), but not for tube drilling (in which margins are not engaged).

scholarly journals An Exploration of Augmented Reality in Computer Assisted Orthopaedic Surgery

10.29007/72d4 ◽  
2018 ◽  
Author(s):  
He Liu ◽  
Edouard Auvinet ◽  
Joshua Giles ◽  
Ferdinando Rodriguez Y Baena
Keyword(s):  
Augmented Reality ◽  
Three Dimensional ◽  
Hole Drilling ◽  
Depth Information ◽  
Computer Assisted ◽  
Pilot Hole ◽  
Surgical Workflow ◽  
Processing Depth ◽  
Computer Assisted Orthopaedic Surgery ◽  
Preoperative Plan

Computer Aided Surgery (CAS) is helpful, but it clutters an already overcrowded operating theatre, and tends to disrupt the workflow of conventional surgery. In order to provide seamless computer assistance with improved immersion and a more natural surgical workflow, we propose an augmented-reality based navigation system for CAS. Here, we choose to focus on the proximal femoral anatomy, which we register to a plan by processing depth information of the surgical site captured by a commercial depth camera. Intra-operative three-dimensional surgical guidance is then provided to the surgeon through a commercial augmented reality headset, to drill a pilot hole in the femoral head, so that the user can perform the operation without additional physical guides. The user can interact intuitively with the system by simple gestures and voice commands, resulting in a more natural workflow. To assess the surgical accuracy of the proposed setup, 30 experiments of pilot hole drilling were performed on femur phantoms. The position and the orientation of the drilled guide holes were measured and compared with the preoperative plan, and the mean errors were within 2mm and 2°, results which are in line with commercial computer assisted orthopedic systems today.

Workpiece Thermal Distortion in Minimum Quantity Lubrication Deep Hole Drilling—Finite Element Modeling and Experimental Validation

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
Bruce L. Tai ◽  
Andrew J. Jessop ◽  
David A. Stephenson ◽  
Albert J. Shih
Keyword(s):  
Heat Flux ◽  
Finite Element ◽  
Heat Carrier ◽  
Three Dimensional ◽  
Minimum Quantity Lubrication ◽  
Hole Drilling ◽  
Bottom Surface ◽  
Thermal Distortion ◽  
Element Analysis ◽  
Minimum Quantity

This paper presents the three dimensional (3-D) finite element analysis (FEA) to predict the workpiece thermal distortion in drilling multiple deep-holes under minimum quantity lubrication (MQL) condition. Heat sources on the drilling hole bottom surface (HBS) and hole wall surface (HWS) are first determined by the inverse heat transfer method. A 3-D heat carrier consisting of shell elements to carry the HWS heat flux and solid elements to carry the HBS heat flux has been developed to conduct the heat to the workpiece during the drilling simulation. A thermal–elastic coupled FEA was applied to calculate the workpiece thermal distortion based on the temperature distribution. The concept of the heat carrier was validated by comparing the temperature calculation with an existing 2-D advection model. The 3-D thermal distortion was validated experimentally on an aluminum workpiece with four deep-holes drilled sequentially. The measured distortion on the reference point was 61 μm, which matches within uncertainty the FEA predicted distortion of 51 μm.

Measurement of Residual Stresses in a Type 316H Stainless Steel Offset Repair in a Pipe Girth Weld

2005 ◽  
Vol 128 (3) ◽  
pp. 420-426 ◽  
Author(s):  
S. Hossain ◽  
C. E. Truman ◽  
D. J. Smith ◽  
P. J. Bouchard
Keyword(s):  
Stainless Steel ◽  
Residual Stresses ◽  
Pipe Wall ◽  
Three Dimensional ◽  
Hole Drilling ◽  
Element Analysis ◽  
Steel Pipes ◽  
Stress Components ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

This paper presents measurements of the in-plane residual stress components through the wall of a 218mm long, 26mm deep repair weld, offset by 7mm from the centerline of a girth weld joining two type 316H stainless steel pipes approximately 37mm thick. The measurements were obtained using the deep hole drilling technique. Two locations were examined: (i) mid-length of the repair weld and (ii) the stop-end of the repair. Both measurements were taken along the girth weld centerline. The distributions and magnitudes of the measured longitudinal and transverse stress components at the two locations were very similar over the outer half of the pipe wall. Over the inner half of the pipe wall both components of stress were found to be significantly more compressive at the stop-end of the repair than at mid-length. In general, the transverse residual stresses were found to be lower than the longitudinal residual stresses at both locations. The measured stress profiles are compared with predicted residual stresses from a three-dimensional finite element analysis.

Study on Finite Element Analysis Models of Slant Rig Working Course

2012 ◽  
Vol 569 ◽  
pp. 363-367
Author(s):  
Fa Guang Jiang ◽  
Zheng Liang ◽  
Li Wen Zhang
Keyword(s):  
Finite Element ◽  
Working Conditions ◽  
Complex Structure ◽  
Three Dimensional ◽  
Influential Factor ◽  
Present Condition ◽  
Hole Drilling ◽  
Element Analysis ◽  
Drilling Rig ◽  
Three Dimensional Finite Element

Slant-hole drilling rig, which can be used to drill inclined well from the ground, is used widely. During designing and research, it is very important to meet working reliability and requirement under various loads and working conditions. As for the complex structure of slant-hole drilling rig, we cannot get the real analytical solutions at present condition. Therefore, the paper establish the three-dimensional finite element models which are about the lifting process and working conditions of slant-hole drilling rig, study the applied loads of each working condition and analyze the stress-strain regulation of slant-hole drilling rig and its influential factor. Based on the analytical results of deformation and stress, an improvement scheme for the slant-hole drilling rig’s structure can is put forward.

scholarly journals Finite Element Analysis and Experimental Evaluation of Residual Stress of Zr-4 alloys Processed through Swaging

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1281 ◽  
Author(s):  
Gaurav Singh ◽  
Bijit Kalita ◽  
K. I. Vishnu Narayanan ◽  
Umesh Kumar Arora ◽  
Manas M. Mahapatra ◽  
...  
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Nuclear Power ◽  
Zirconium Alloy ◽  
True Strain ◽  
Three Dimensional ◽  
Element Model ◽  
Hole Drilling ◽  
Element Analysis ◽  
Hole Drilling Method

Zirconium alloy has been extensively used as a cladding material in nuclear power reactors due to its low neutron absorption cross section, excellent mechanical properties, and corrosion resistance. The influence of the swaging parameter, feed rate (0.7, 1.25, 2 m/min) on residual stress induced in Zr-4 alloy is investigated in the present work. A three-dimensional finite element model was implemented in the Deform 3D software to simulate the rotary swaging (RS) process over a circular rod of Zr-4 alloy. The simulation results based on the 3D framework provide a detailed insight of residual stress, true stress versus true strain and force applied over the rod during the multiple pass swaging process; the results are compared with experimental results. The experimental hole drilling method is used to determine the residual stresses on swaged zirconium alloy at different feed rates (0.7, 1.25, and 2 m/min). A similar trend of residual stress between experimental and numerical results from the surface to the center on the swaged rod samples is observed. The same magnitude of residual stress at the surface of the swaged Zr-4 rod is also observed. It is found to be compressive at the surface and tensile in the center of the samples, as observed in the present work.

Measurement of Residual Stresses in a Type 316H Stainless Steel Offset Repair in a Pipe Girth Weld

2004 ◽  
Author(s):  
S. Hossain ◽  
C. E. Truman ◽  
D. J. Smith ◽  
P. J. Bouchard
Keyword(s):  
Stainless Steel ◽  
Residual Stresses ◽  
Pipe Wall ◽  
Three Dimensional ◽  
Hole Drilling ◽  
Element Analysis ◽  
Steel Pipes ◽  
Stress Components ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

This paper presents measurements of the in-plane residual stress components through the wall of a 218mm long, 26mm deep repair weld, offset by 7mm from the centreline of a girth weld joining two type 316H stainless steel pipes approximately 37mm thick. The measurements were obtained using the deep hole drilling technique. Two locations were examined: (i) mid-length of the repair weld and (ii) the stop-end of the repair. Both measurements were taken along the girth weld centreline. The distributions and magnitudes of the measured longitudinal and transverse stress components at the two locations were very similar over the outer half of the pipe wall. Over the inner half of the pipe wall both components of stress were found to be significantly more compressive at the stop-end of the repair than at mid-length. In general, the transverse residual stresses were found to be lower than the longitudinal residual stresses at both locations. The measured stress profiles are compared with predicted residual stresses from a three dimensional finite element analysis for a similar weld repair.

Mitochondrial Reconstructions Based on Serial Thick Sections and HVEM

1975 ◽  
Vol 33 ◽  
pp. 286-287
Author(s):  
Jerome J. Paulin
Keyword(s):  
Imaging Techniques ◽  
Three Dimensional ◽  
Posterior Pole ◽  
Dimensional Structure ◽  
Stereo Imaging ◽  
Thin Sections ◽  
Anatomical Features ◽  
The Past ◽  
Cellular Components ◽  
Mitochondrial Reticulum

Within the past decade it has become apparent that HVEM offers the biologist a means to explore the three-dimensional structure of cells and/or organelles. Stereo-imaging of thick sections (e.g. 0.25-10 μm) not only reveals anatomical features of cellular components, but also reduces errors of interpretation associated with overlap of structures seen in thick sections. Concomitant with stereo-imaging techniques conventional serial Sectioning methods developed with thin sections have been adopted to serial thick sections (≥ 0.25 μm). Three-dimensional reconstructions of the chondriome of several species of trypanosomatid flagellates have been made from tracings of mitochondrial profiles on cellulose acetate sheets. The sheets are flooded with acetone, gluing them together, and the model sawed from the composite and redrawn.The extensive mitochondrial reticulum can be seen in consecutive thick sections of (0.25 μm thick) Crithidia fasciculata (Figs. 1-2). Profiles of the mitochondrion are distinguishable from the anterior apex of the cell (small arrow, Fig. 1) to the posterior pole (small arrow, Fig. 2).

Effects of occlusal scheme on All-on-Four abutments, screws and prostheses: A three-dimensional finite element study

2020 ◽  
Author(s):  
Nurullah Türker ◽  
Hümeyra Tercanlı Alkış ◽  
Steven J Sadowsky ◽  
Ulviye Şebnem Büyükkaplan
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Good Prognosis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Group Function ◽  
Occlusal Contact ◽  
Maximum Deformation ◽  
Contact Points ◽  
Von Mises

An ideal occlusal scheme plays an important role in a good prognosis of All-on-Four applications, as it does for other implant therapies, due to the potential impact of occlusal loads on implant prosthetic components. The aim of the present three-dimensional (3D) finite element analysis (FEA) study was to investigate the stresses on abutments, screws and prostheses that are generated by occlusal loads via different occlusal schemes in the All-on-Four concept. Three-dimensional models of the maxilla, mandible, implants, implant substructures and prostheses were designed according to the All-on-Four concept. Forces were applied from the occlusal contact points formed in maximum intercuspation and eccentric movements in canine guidance occlusion (CGO), group function occlusion (GFO) and lingualized occlusion (LO). The von Mises stress values for abutment and screws and deformation values for prostheses were obtained and results were evaluated comparatively. It was observed that the stresses on screws and abutments were more evenly distributed in GFO. Maximum deformation values for prosthesis were observed in the CFO model for lateral movement both in the maxilla and mandible. Within the limits of the present study, GFO may be suggested to reduce stresses on screws, abutments and prostheses in the All-on-Four concept.

Towards Predicting Relative Belt Edge Endurance With the Finite Element Method

1990 ◽  
Vol 18 (4) ◽  
pp. 216-235 ◽  
Author(s):  
J. De Eskinazi ◽  
K. Ishihara ◽  
H. Volk ◽  
T. C. Warholic
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Shear Deformations ◽  
Element Analysis ◽  
Vertical Loading ◽  
Predicted Values ◽  
Element Method

Abstract The paper describes the intention of the authors to determine whether it is possible to predict relative belt edge endurance for radial passenger car tires using the finite element method. Three groups of tires with different belt edge configurations were tested on a fleet test in an attempt to validate predictions from the finite element results. A two-dimensional, axisymmetric finite element analysis was first used to determine if the results from such an analysis, with emphasis on the shear deformations between the belts, could be used to predict a relative ranking for belt edge endurance. It is shown that such an analysis can lead to erroneous conclusions. A three-dimensional analysis in which tires are modeled under free rotation and static vertical loading was performed next. This approach resulted in an improvement in the quality of the correlations. The differences in the predicted values of various stress analysis parameters for the three belt edge configurations are studied and their implication on predicting belt edge endurance is discussed.

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