Stress Concentrations at the Rounded Edges of a Shaft-Hub Interference Fit Expressed in Terms of a Coefficient Normalizing the Coupling Geometry and the Young’s Modulus Effects

2012 ◽  
Author(s):  
Antonio Strozzi ◽  
Andrea Baldini ◽  
Matteo Giacopini ◽  
Enrico Bertocchi ◽  
Luca Bertocchi
Keyword(s):  
Stress Concentration ◽  
Young’S Modulus ◽  
Elastic Stress ◽  
Young's Modulus ◽  
Outer Radius ◽  
Stress Concentrations ◽  
Interference Fit ◽  
Press Fit ◽  
Fillet Radius ◽  
Inner Radius

The elastic stress concentrations developed from the keyless, frictionless, static press-fit of a solid shaft into a hub with bore rounded edges are addressed. Derived from an analytical approach, a normalising parameter Φ is employed that accounts for the combined effects on the hub stress concentration of the fillet radius of the hub bore, the shaft radius, the interference, and the Young’s modulus. Compiled with the aid of Finite Elements, several design charts are presented that report the elastic stress concentrations within the hub versus the normalising parameter Φ. Each curve is valid for prescribed ratios of a) the hub inner radius to the outer radius, and b) the fillet radius to the shaft radius. An approximating expression of ample validity is also presented for a prompt evaluation of the hub stress concentration factor.

Elastic Stress Concentrations for the Torsion of Hollow Shouldered Shafts Determined by an Electrical Analogue

1964 ◽  
Vol 15 (1) ◽  
pp. 83-96 ◽  
Author(s):  
K. R. Rushton
Keyword(s):  
Stress Concentration ◽  
Elastic Stress ◽  
Plastic Region ◽  
Stress Concentrations ◽  
Electrical Analogue ◽  
Shoulder Diameter ◽  
Concentration Factors ◽  
Stress Concentration Factors

SummaryThe elastic stress concentration factors for the torsion of solid and hollow shouldered shafts have been determined by means of a pure resistance electrical analogue. Fillet radii ranged from 0.05 to 1.0 times the diameter of the smaller shaft, and the shoulder diameter increased from 1.0 to 8.10 times the diameter of the smaller shaft. A comparison is made with the results of other techniques. A study has also been made of the formation of a plastic region in the neighbourhood of the fillet.

scholarly journals Characterization of the microstructural components and corrosion-induced changes in the mechanical properties of oolitic limestone

2020 ◽  
Vol 205 ◽  
pp. 03011
Author(s):  
Aránzazu Piñán-Llamas ◽  
Fawad S. Niazi ◽  
Colton Amstutz ◽  
Zachary Brown
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Exposure Time ◽  
Chemical Weathering ◽  
Young's Modulus ◽  
Triaxial Compression ◽  
Effective Porosity ◽  
Peak Strength ◽  
Stress Concentrations ◽  
Oolitic Limestone

The understanding of the variation of mechanical properties and microstructural changes of rocks due to chemical weathering is critical for prospection, extraction and storage of energy resources in the subsurface. Uniaxial and triaxial compression tests were conducted on fresh and chemically weathered oolitic limestone samples submerged in acidic solutions with pH5 and pH3 values for 30 and 50 days each. Results show that both, acid concentration and exposure period have a significant influence not only in changes of effective porosity, Young’s modulus and peak strength, but also in the development of stress-induced microstructures. While the change in effective porosity increased and the Young’s modulus decreased with exposure time, the peak strength decreased with exposure time and decreasing pH. Micro-fracturing, twinning, and rigid body rotation were the main mechanisms of the deformations observed. The highest density of microcracks and twinned grains were observed in samples subjected to longer exposure periods of time, suggesting that the exposure time constitutes an essential factor in rock softening. Microfracturing initiated at grain boundaries, where stress concentrations were higher. In agreement with previous work on limestone inelastic compaction, the mechanical contrast of allochemical components with respect to cement conditioned the spatial distribution of the microfractures.

The Influence of the Coefficient of Friction on the Elastic Stress Concentration Factor for a Pin-Jointed Connection

1962 ◽  
Vol 13 (1) ◽  
pp. 17-29 ◽  
Author(s):  
T. H. Lambert ◽  
R. J. Brailey
Keyword(s):  
Shear Stress ◽  
Stress Concentration ◽  
Coefficient Of Friction ◽  
Stress Concentration Factor ◽  
Elastic Stress ◽  
Maximum Shear Stress ◽  
Interference Fit ◽  
Stress Load ◽  
The Coefficient Of Friction ◽  
Very High

SummaryThe benefit to be obtained by using an interference fit between the pin and plate in a pin-jointed connection has already been established. An examination of the published results shows that some non-linearity occurs in the mechanism of load transference from the pin to the plate since, except at very high initial interference, doubling the load on the joint more than doubles the maximum shear stress in the plate. An examination of the stress-load relationship shows a distinct discontinuity, the load at which this discontinuity occurs being dependent upon both the initial interference and the coefficient of friction between the pin and the plate. It is shown that the results hitherto published correspond to a coefficient of friction between the pin and the plate of 0.3 and results for lower and higher coefficients are given.

scholarly journals Experimental Investigation of Stress Distributions in 3D Printed Graded Plates with a Circular Hole

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7845
Author(s):  
Quanquan Yang ◽  
He Cao ◽  
Youcheng Tang ◽  
Yun Li ◽  
Xiaogang Chen
Keyword(s):  
Experimental Investigation ◽  
Stress Concentration ◽  
Young’S Modulus ◽  
Circular Hole ◽  
Young's Modulus ◽  
Theoretical Models ◽  
Research Field ◽  
Functionally Graded ◽  
Stress Distributions ◽  
Functionally Graded Plates

An experimental investigation is presented for the stress distributions in functionally graded plates containing a circular hole. On the basis of the authors’ previously constructed theoretical model, two kinds of graded plates made of discrete rings with increasing or decreasing Young’s modulus were designed and fabricated in virtue of multi-material 3D printing. The printed graded plates had accurate size, smooth surface, and good interface. The strains of two graded plates under uniaxial tension were measured experimentally using strain gages. The stresses were calculated within the range of linear elastic from the measured strains and compared with analytical theory. It is found that the experimental results are consistent with the theoretical results, and both of them indicate that the stress concentration around the hole reduces obviously in graded plates with radially increasing Young’s modulus, in comparison with that of perforated homogenous plates. The successful experiment in the paper provides a good basis and support for the establishment of theoretical models and promotes the in-depth development of the research field of stress concentration in functionally graded plates.

A note on the elastic stress in tunnel linings

1966 ◽  
Vol 1 (2) ◽  
pp. 110-114
Author(s):  
D. W. Jordan
Keyword(s):  
Tensile Stress ◽  
Young’S Modulus ◽  
Circumferential Strain ◽  
Elastic Stress ◽  
Young's Modulus ◽  
Surrounding Rock ◽  
Tunnel Lining ◽  
Circular Tunnel ◽  
Qualitative Discussion ◽  
Different Young’S Modulus

A circular tunnel lining is idealized as a perfectly elastic annulus either keyed to, or a sliding fit in a hole in an infinite elastic medium of different Young's modulus, the system being under stress at infinity. The solution to this problem is used to give a qualitative discussion of two situations: 1 The resistance of a tunnel lining is limited amongst other things by its inability to withstand tensile stress. It is shown that in the above idealization, the more flexible the lining the less likely are tensions to arise. Such flexibility might be achieved by allowing the lining freedom to slide relative to the surrounding rock rather than by keying it to the walls, by making it of laminated construction or by lowering its Young's modulus. Increasing the thickness may increase the liability to tension. 2 As a means of estimating the load on a lining, gauges may be placed to measure circumferential strain, and from these measurements the load is deduced by assuming that the lining behaves like a bending beam. A difficulty in interpreting such measurements is pointed out in the case of a keyed lining, when the shearing stresses are very large.

An Analytical Approach to Reduce the Stress Concentration around a Circular Hole in a Functionally Graded Material Plate under Axial Load

2014 ◽  
Vol 592-594 ◽  
pp. 985-989 ◽  
Author(s):  
Mayank Kushwaha ◽  
Parveen K. Saini
Keyword(s):  
Stress Concentration ◽  
Young’S Modulus ◽  
Functionally Graded Material ◽  
Young's Modulus ◽  
Axial Loading ◽  
Functionally Graded ◽  
Complex Variable Function ◽  
Variable Function ◽  
Graded Material ◽  
Circular Cutout

This paper presents an analytical method to reduce the stress concentration in a functionally graded material (FGM) plate, having a circular cutout, under axial loading. An exponential radial variation and the variation by the power law, of the Young’s modulus is assumed here. This is achieved by decomposing the plate into a number of rings. Muskhelishivili’s method of the complex variable function is used for this piece of work study of stress distribution in the plate. It is observed that the stress concentration decreases as the Young’s modulus increases radially away from the hole.

scholarly journals Stress concentrations at an oblique hole in a thick plate

2000 ◽  
Vol 35 (2) ◽  
pp. 143-147 ◽  
Author(s):  
P Stanley ◽  
A G Starr
Keyword(s):  
Stress Concentration ◽  
Flat Plate ◽  
Uniaxial Tension ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Thick Plate ◽  
Empirical Equation ◽  
Elastic Stress ◽  
Cylindrical Hole ◽  
Stress Concentrations

An empirical equation has been obtained for the elastic stress concentration factor at an isolated oblique circular-cylindrical hole in a thick flat plate subjected to a uniform, arbitrarily oriented uniaxial tension. The equation is presented and its development is outlined in this note.

scholarly journals Effect of the material’s stiffness on stress-shielding in osseointegrated implants for bone-anchored prostheses: a numerical analysis and initial benchmark data

2020 ◽  
Vol 22 (2) ◽  
Author(s):  
Piotr Prochor ◽  
Laurent Frossard ◽  
Eugeniusz Sajewicz
Keyword(s):  
Bone Mass ◽  
Young’S Modulus ◽  
Distal Femur ◽  
Young's Modulus ◽  
Stress Shielding ◽  
Term Stability ◽  
Long Term Stability ◽  
Press Fit ◽  
Material Stiffness

Purpose: This study attempted to establish the link between design of implants for bone-anchored prostheses and stress-shielding, affecting the stability of the bone-implant coupling using numerical approach. The objectives were to share a numerical model capable to evaluate the long-term stability of implants and to use this model to extract data sets showing how shape and material stiffness of threaded, press-fit and modular press-fit implants affect stress-shielding intensity. Methods: Three designs were considered: threaded, press-fit and modular press-fit. The effect of shape and material stiffness of each design on stress-shielding intensity was assessed using Young’s modulus (10 to 210 GPa). Furthermore, the impact of the diameter of percutaneous part (10 to 18 mm) and thickness of medullar part (5 to 1 mm) was investigated for the modular press-fit implant. Results: The threaded design generated 4% more bone mass loss at the distal femur but an overall loss of bone mass was by 5% lower to press-fit design. The influence of Young’s modulus on bone mass changes was noticeable for modular press-fit implant, depending on diameter of percutaneous or medullary part. A 20 GPa change of stiffness caused a bone mass change from 0.65% up to 2.45% and from 0.07% up to 0.32% for percutaneous parts with 18 mm and 10 mm diameter, respectively. Conclusions: Results suggested that threaded implant provides greater stability despite an increased bone loss at the distal femur. Altogether, this work provided an initial model that could be applied in subsequent studies on the long-term stability of current and upcoming implants.

scholarly journals Measurement of interface pressure in interference fits

2005 ◽  
Vol 219 (2) ◽  
pp. 127-139 ◽  
Author(s):  
R Lewis ◽  
M B Marshall ◽  
R S Dwyer-Joyce
Keyword(s):  
Contact Pressure ◽  
Central Region ◽  
Contact Stiffness ◽  
Surface Damage ◽  
Calibration Procedure ◽  
Stress Concentrations ◽  
Interference Fit ◽  
Press Fit ◽  
Reflection Data ◽  
Shrink Fit

When components such as bearings or gears are pressed onto a shaft, the resulting interference induces a pressure at the interface. The size of this pressure is important as many components fail because fatigue initiates from press-fit stress concentrations. The aim of the present work was to develop ultrasound as a tool for non-destructive determination of press-fit contact pressures. An interference fit interface behaves like a spring. If the pressure is high, there are few air gaps, so it is very stiff and allows transmission of an ultrasonic wave. If the pressure is low, then interface stiffness is lower and most ultrasound is reflected. A spring model was used to determine maps of contact stiffness from interference-fit ultrasonic reflection data. A calibration procedure was then used to determine the pressure. The interface contact pressure has been determined for a number of different press- and shrink-fit cases. The results show a central region of approximately uniform pressure with edge stress at the contact sides. The magnitude of the pressure in the central region agrees well with the elastic Lamé analysis. In the more severe press-fit cases, the surfaces scuffed which led to anomalies in the reflected ultrasound. These anomalies were associated with regions of surface damage at the interface. The average contact pressure in a shrink-fit and press-fit joint were similar. However, in the shrink-fit joint more uneven contact pressure was observed with regions of poor conformity. This could be because the action of pressing on a sleeve plastically smooths out long wavelength roughness, leading to a more conforming surface.

Stress Concentrations in Tensile Strips with Central Notches of Varying End Radii

1962 ◽  
Vol 66 (617) ◽  
pp. 323-326 ◽  
Author(s):  
Ralph Papirno
Keyword(s):  
Stress Concentration ◽  
Excellent Agreement ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Elastic Stress ◽  
Finite Width ◽  
Stress Concentrations ◽  
Fixed Length ◽  
Tensile Strip ◽  
Image Position

SummaryUsing relations derived by Dixon and Inglis, the values of the elastic stress concentration factor for a fixed length notch in a finite width tensile strip with a varying notch end radius have been obtained in the form:Photoelastic tests on internally notched tensile strip models showed excellent agreement with the analytical results.

Sign in / Sign up

Export Citation Format

Share Document