Use of staircase method to validate a new design of engine pulley

2020 ◽  
Author(s):  
Tadeus Marchesi ◽  
Wagner Trindade
Keyword(s):  
Staircase Method

scholarly journals S235JRC+C Steel Response Analysis Subjected to Uniaxial Stress Tests in the Area of High Temperatures and Material Fatigue

2021 ◽  
Vol 13 (10) ◽  
pp. 5675
Author(s):  
Josip Brnic ◽  
Marino Brcic ◽  
Sebastian Balos ◽  
Goran Vukelic ◽  
Sanjin Krscanski ◽  
...  
Keyword(s):  
High Temperatures ◽  
Room Temperature ◽  
Uniaxial Stress ◽  
Fatigue Tests ◽  
Experimental Investigations ◽  
Response Analysis ◽  
Stress Tests ◽  
Staircase Method ◽  
Mechanical Fatigue ◽  
Proper Material

Knowledge of the properties and behavior of materials under certain working conditions is the basis for the selection of the proper material for the design of a new structure. This paper deals with experimental investigations of the mechanical properties of unalloyed high quality steel S235JRC + C (1.0122) and its behavior under conditions of high temperatures, creep and mechanical fatigue. The response of the material at high temperatures (20–700 °C) is shown in the form of engineering stress-strain diagrams while that at creep behavior (400–600 °C) is shown in the form of creep curves. Furthermore, based on uniaxial fully reversed mechanical fatigue tests (R=−1), a stress-life (S-N) fatigue diagram has been constructed and the fatigue (endurance) limit of the material is calculated The experimentally determined value of tensile strength at room temperature is 534 MPa. The calculated value of the fatigue limit, also at room temperature, using the modified staircase method and based on the mechanical fatigue tests data, is 202 MPa. With regard to creep resistance, steel 1.0122 can be considered creep-resistant only at a temperature of 400 °C and at an applied stress not exceeding 50% of the yield strength corresponding to this temperature.

scholarly journals Fatigue Strength Analysis of S34MnV Steel by Accelerated Staircase Test

2020 ◽  
Vol 10 (1) ◽  
pp. 394-400 ◽  
Author(s):  
I. M. W. Ekaputra ◽  
Rando Tungga Dewa ◽  
Gunawan Dwi Haryadi ◽  
Seon Jin Kim
Keyword(s):  
Standard Deviation ◽  
Fatigue Strength ◽  
Fatigue Limit ◽  
Fatigue Testing ◽  
Reliability Estimation ◽  
Test Method ◽  
Strength Analysis ◽  
Staircase Method ◽  
Staircase Test ◽  
Number Of Cycles

AbstractThis paper presents the reliability estimation of fatigue strength of the material used for crank throw components. The material used for crank throw components is forged S34MnV steel and subsequently heat-treated by normalising and tempering. High cycle fatigue testing under fully reversed cycling (R = −1) was performed to determine the fatigue limit of the material. The staircase test method is used to obtain accurate values of the mean fatigue limit stress until a number of cycles up to 1E7 cycles. Subsequently, the fatigue test results depend strongly on the stress step and are evaluated by the Dixon-Mood formula. The values of mean fatigue strength and standard deviation predicted by the staircase method are 282 MPa and 10.6MPa, respectively. Finally, the reliability of the design fatigue strength in some selected probability of failure is calculated. Results indicate that the fatigue strength determined from accelerated staircase test is consistent with conventional fatigue testing. Furthermore, the proposed method can be applied for the determination of fatigue strength and standard deviation for design optimisation of S34MnV steel.

Temporal-Discontinuity Detection with Contrast-Modulated Gratings

Perception ◽  
1995 ◽  
Vol 24 (11) ◽  
pp. 1257-1264
Author(s):  
Shigeru Ichihara ◽  
Kenji Susami
Keyword(s):  
Spatial Frequency ◽  
Modulation Frequency ◽  
Sinusoidal Grating ◽  
Local Contrast ◽  
Staircase Method ◽  
Low Contrast ◽  
Discontinuity Detection ◽  
Temporal Discontinuity ◽  
Sinusoidal Gratings ◽  
The Subject

Three experiments on temporal-discontinuity detection were carried out. In experiment 1, temporal-discontinuity thresholds were measured for sinusoidal gratings by the use of the double-staircase method. A sinusoidal grating was presented twice successively. The subject judged whether or not an interval was present. The temporal-discontinuity threshold increased as the spatial frequency of the grating increased, but decreased as the contrast of the grating increased. In experiment 2, contrast-modulated gratings were used instead of the sinusoidal grating. The temporal-discontinuity threshold increased as the carrier frequency increased, and the threshold for each contrast-modulated grating was similar to that for the no-modulation (sinusoidal) grating whose contrast was the same as the maximum local contrast of the contrast-modulated grating. In experiment 3, temporal-discontinuity thresholds were measured for low-contrast (3%) sinusoidal gratings. The thresholds were very low, even for such low-contrast gratings. These results suggest that the low-spatial-frequency channels are not involved in detecting the modulation frequency of the contrast-modulated grating. Rather, the local contrast seems to be the determinant of the detection of the contrast-modulated grating itself.

Effect of Phosphoric Acid Pre-etching on Fatigue Limits of Self-etching Adhesives

2015 ◽  
Vol 40 (4) ◽  
pp. 379-395 ◽  
Author(s):  
T Takamizawa ◽  
WW Barkmeier ◽  
A Tsujimoto ◽  
DD Scheidel ◽  
RL Erickson ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Fatigue Testing ◽  
Resin Composite ◽  
Metal Ring ◽  
Staircase Method ◽  
Shear Fatigue ◽  
Human Enamel ◽  
Tooth Surfaces ◽  
Post Hoc ◽  
Self Etch

SUMMARY The purpose of this study was to use shear bond strength (SBS) and shear fatigue limit (SFL) testing to determine the effect of phosphoric acid pre-etching of enamel and dentin prior to application of self-etch adhesives for bonding resin composite to these substrates. Three self-etch adhesives—1) G- ænial Bond (GC Corporation, Tokyo, Japan); 2) OptiBond XTR (Kerr Corp, Orange, CA, USA); and 3) Scotchbond Universal (3M ESPE Dental Products, St Paul, MN, USA)—were used to bond Z100 Restorative resin composite to enamel and dentin surfaces. A stainless-steel metal ring with an inner diameter of 2.4 mm was used to bond the resin composite to flat-ground (4000 grit) tooth surfaces for determination of both SBS and SFL. Fifteen specimens each were used to determine initial SBS to human enamel/dentin, with and without pre-etching with a 35% phosphoric acid (Ultra-Etch, Ultradent Products Inc, South Jordan, UT, USA) for 15 seconds prior to the application of the adhesives. A staircase method of fatigue testing (25 specimens for each test) was then used to determine the SFL of resin composite bonded to enamel/dentin using a frequency of 10 Hz for 50,000 cycles or until failure occurred. A two-way analysis of variance and Tukey post hoc test were used for analysis of SBS data, and a modified t-test with Bonferroni correction was used for the SFL data. Scanning electron microscopy was used to examine the area of the bonded restorative/tooth interface. For all three adhesive systems, phosphoric acid pre-etching of enamel demonstrated significantly higher (p<0.05) SBS and SFL with pre-etching than it did without pre-etching. The SBS and SFL of dentin bonds decreased with phosphoric acid pre-etching. The SBS and SFL of bonds using phosphoric acid prior to application of self-etching adhesives clearly demonstrated different tendencies between enamel and dentin. The effect of using phosphoric acid, prior to the application of the self-etching adhesives, on SBS and SFL was dependent on the adhesive material and tooth substrate and should be carefully considered in clinical situations.

Enamel Etching for Universal Adhesives: Examination of Enamel Etching Protocols for Optimization of Bonding Effectiveness

2020 ◽  
Vol 45 (1) ◽  
pp. 80-91
Author(s):  
J Wong ◽  
A Tsujimoto ◽  
NG Fischer ◽  
AG Baruth ◽  
WW Barkmeier ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Surface Area ◽  
Adhesive Bonding ◽  
Sine Wave ◽  
Etching Time ◽  
Universal Adhesive ◽  
Staircase Method ◽  
Ground Enamel ◽  
Fatigue Durability ◽  
Universal Adhesives

SUMMARY Objective: The purpose of this study was to evaluate whether different enamel etching methods with reduced etching times would improve the bonding effectiveness of universal adhesives. Methods and Materials: Three enamel etching methods, phosphoric acid ester monomer (PPM) etching, phosphoric acid (PPA) etching, and polyalkenoic acid (PLA) etching, and three universal adhesives, G-Premio Bond (GP), Prime&Bond elect (PE), and Scotchbond Universal Adhesive (SU), were evaluated. Initial bond strengths and fatigue strengths of universal adhesives to ground enamel and ground enamel etched for less than one, five, 10, and 15 seconds using different etching methods were determined. The bonded fatigue specimens were loaded using a sine wave at a frequency of 20 Hz for 50,000 cycles or until failure occurred with a staircase method. Atomic force micrograph (AFM) observations along with measurements of surface Ra roughness and modified surface area of enamel with different etching protocols were also conducted. Results: The bond fatigue durability of universal adhesives to enamel with PPA etching from less than one to 15 seconds and PLA etching for 15 seconds was significantly higher than that to ground enamel. The bond fatigue durability to enamel with PPM etching was not increased compared with ground enamel. The surface Ra roughness and surface area obtained with AFM of enamel increased after PPA and PLA etching, and those values were significantly higher than those of ground enamel. Furthermore, surface Ra roughness and surface area with PPA etching were significantly higher than those with PLA etching. However, surface Ra roughness and surface area of enamel with PPM etching were similar to those of ground enamel regardless of etching time. Conclusion: PPA etching for less than one to 15 seconds and PLA etching for 15 seconds improve universal adhesive bonding, surface Ra roughness, and surface area of enamel. However, PPM etching is not effective, regardless of etching time, in improving bonds strengths, increasing surface roughness, and increasing surface area.

Alternative Method for the Determination of a Full S-N Fatigue Profile

2016 ◽  
Vol 250 ◽  
pp. 209-216 ◽  
Author(s):  
Przemysław Strzelecki ◽  
Janusz Sempruch ◽  
Tomasz Tomaszewski
Keyword(s):  
Fatigue Life ◽  
Linear Regression ◽  
Fatigue Limit ◽  
Fatigue Curve ◽  
The Other ◽  
Staircase Method ◽  
Alternative Method ◽  
Random Fatigue

This paper presents two methods for estimating the S-N fatigue curve. The first is the traditional linear regression and staircase method. The other, alternative, method is based on random fatigue life, fatigue limit and probability. The both methods provide similar results but the latter one requires fewer test samples

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