Investigation of insert-hole interference fit influence on downhole drilling bit failure

2020 ◽  
Vol 234 (14) ◽  
pp. 1752-1761
Author(s):  
R Saeedi ◽  
MH Sadeghi
Keyword(s):  
Three Dimensional ◽  
Fatigue Tests ◽  
Hole Drilling ◽  
Interference Fit ◽  
Dimensional Finite Element ◽  
Manufacturing Tolerances ◽  
Three Dimensional Finite Element ◽  
Bit Life ◽  
Drilling Bit ◽  
Fitting Interference

Down-the-hole drilling is a reliable method for drilling in medium-to-hard geological structures. The insert-hole fitting interference value emerges as one of the most important factors of down-the-hole drilling bit life. In this study, fatigue tests were conducted using a tungsten carbide pin press-fitted into a hole in the specimens of DIN 1.6580 steel (which is used for manufacturing the bit body) to quantify the effect of interference value on the bit body failure. Then, the process of bit-rock collision was simulated using three-dimensional finite element method taking into account the residual stresses in the insert and bit body to determine the optimal interference value. Simulations were performed considering the rotary motion of the bit in addition to impact for a single-insert as well as a commercial 3.5 inch bit. Results showed that the interference value influences fatigue life significantly. Also, the velocity and angle of impact have considerable influence on body stresses. Results of this study can greatly assist the design of insert-hole manufacturing tolerances in down-the-hole bits.

Analytical Study of Fatigue Cracking in Coped Stringers of Steel Bridges

2019 ◽  
Vol 2673 (10) ◽  
pp. 239-246
Author(s):  
Alireza Mohammadi ◽  
Walid S. Najjar
Keyword(s):  
Tensile Stress ◽  
Stress Reduction ◽  
Analytical Study ◽  
Three Dimensional ◽  
Fatigue Cracking ◽  
Hole Drilling ◽  
Finite Element Models ◽  
High Concentration ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Typical coped stringers of streel bridges are prone to fatigue cracking as a result of the high concentration of tensile stress in the cope zone. This stress concentration is caused by a combination of geometric discontinuity at the cope radius and end-connection rigidity. Few retrofit methods are available for mitigating this cracking; they include hole drilling at a crack tip, and top-rivet removal from a stringer-floorbeam connection. Three-dimensional finite element models of a typical stringer with coped web were developed and analyzed to evaluate (i) cope geometry and load configuration parameters and (ii) the effectiveness of these two retrofit methods. The studied geometry parameters were cope radius and cope length. Variations in the cope-zone stress distribution for each parameter and between an original and a retrofitted condition are presented in this paper. Tensile stress reduction was associated with increased cope radius. Although hole drilling resulted in significant stress reduction along the cope edge, this method was associated with increased tensile stress at the bottom of the drilled hole, which could result in further crack propagation. This finding is consistent with existing studies. Removal of a top rivet resulted in significant reduction of tensile stress.

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.

Fatigue Behavior and Deformation of Aluminum and Steel HVOF Sprayed with WC-Co Coatings

1997 ◽  
Author(s):  
A. Ibrahim ◽  
C.C. Berndt
Keyword(s):  
Fatigue Life ◽  
Room Temperature ◽  
Fatigue Behavior ◽  
Three Dimensional ◽  
Element Model ◽  
Fatigue Tests ◽  
Dimensional Finite Element ◽  
Life Distributions ◽  
Three Dimensional Finite Element ◽  
Good Agreement

Abstract The effect of WC-Co coating on the high cycle fatigue (HCF) behavior of SAE 12L14 steel and 2024-T4 aluminum was investigated. The fatigue tests were performed at room temperature and 370°C. The fatigue life distributions of specimens in the polished, grit blasted, peened, and coated conditions are presented as a function of the probability of failure. HVOF sprayed WC-Co coating has influenced the fatigue life of aluminum and steel. Factors contributing to this influence, which include grit blasting, elastic modulus, and residual stress, are discussed. A three-dimensional finite-element model (FEM) of the coated specimen was used to calculate the stress distribution across the coating and the substrate. The results of the analytical model are in good agreement with fatigue lives observed experimentally.

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.

The Hollow-Ended Roller—A Solution for Improving Fatigue Life in Asymmetrically Loaded Cylindrical Roller Bearings

1972 ◽  
Vol 94 (2) ◽  
pp. 153-162 ◽  
Author(s):  
W. J. Derner ◽  
R. A. Goodelle ◽  
L. E. Root ◽  
R. Rung
Keyword(s):  
Three Dimensional ◽  
Fatigue Tests ◽  
Hertzian Contact ◽  
Heavy Load ◽  
Roller Bearings ◽  
Equal Importance ◽  
Dimensional Finite Element ◽  
Hertzian Contact Stress ◽  
Three Dimensional Finite Element ◽  
Cylindrical Roller

To reduce the influence of misalignment (asymmetrical loading) on cylindrical roller bearings it is necessary to supplement the crown modifications of bearing elements. A unique hollow-ended roller design was developed for this purpose employing a three-dimensional finite element elasticity study to determine the stress state in the flexible rim section. The results when combined with the classical Hertzian contact stress distribution result in an accurate description of the shear stress field throughout the roller rim sections. Results of fatigue tests run under asymmetrically distributed loads supported the analytical efforts demonstrating significant improvements in L10 lives for the hollow-ended roller as compared to a solid roller. Peak stresses occurred in the vicinity of the contact area for both types of rollers with the solid exhibiting stresses 5 percent or more higher than those found in the hollow-ended type. Of equal importance, the observed failure mode for hollow-ended rollers under heavy load fatigue test conditions is one of conventional subsurface initiated O.D. spalling, thereby proving the rim design to be structurally sound.

Finite Element Analysis on Fatigue of Train Axle

2011 ◽  
Vol 66-68 ◽  
pp. 1090-1093 ◽  
Author(s):  
Guang Xue Yang ◽  
Qiang Li ◽  
Ji Long Xie
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Lateral Load ◽  
Vertical Load ◽  
Element Analysis ◽  
Interference Fit ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Fretting Damage

In this paper, aimed at wheel-axle with axle load of 30 ton, the three dimensional finite element model was established, and the interference fit between wheel and axle was considered. According to Standard EN13103, the vertical load and the lateral load were determined, and then the stress distribution of axle was computed under two cases: only vertical load and both vertical and lateral load. The result shows that: the increase of axle load causes the increase of slip between axle and hub, which leads to an increase of fretting damage and a reduction in fatigue life. In addition, Dang Van criterion was employed to evaluate the fatigue of the whole axle. It is found that the transition zone next to wheel seat and the interface of hub and axle are dangerous points, which is in accordance with the practice.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

Tire Modeling by Finite Elements

1992 ◽  
Vol 20 (1) ◽  
pp. 33-56 ◽  
Author(s):  
L. O. Faria ◽  
J. T. Oden ◽  
B. Yavari ◽  
W. W. Tworzydlo ◽  
J. M. Bass ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Rolling Contact ◽  
Test Problems ◽  
State Behavior ◽  
Normal Contact ◽  
New Developments ◽  
Applied Torque ◽  
Dimensional Finite Element ◽  
Tire Modeling ◽  
Three Dimensional Finite Element

Abstract Recent advances in the development of a general three-dimensional finite element methodology for modeling large deformation steady state behavior of tire structures is presented. The new developments outlined here include the extension of the material modeling capabilities to include viscoelastic materials and a generalization of the formulation of the rolling contact problem to include special nonlinear constraints. These constraints include normal contact load, applied torque, and constant pressure-volume. Several new test problems and examples of tire analysis are presented.

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