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.

The Evaluation of Bending Fatigue Testing of Austempered Ductile Iron Spur Gear

2019 ◽  
Author(s):  
Qi Zhang ◽  
Jianhua Lv ◽  
Rizwanulhaque Syed ◽  
Jing Zhang ◽  
Yang Xu ◽  
...  
Keyword(s):  
Fatigue Strength ◽  
Ductile Iron ◽  
Fatigue Testing ◽  
Spur Gear ◽  
Austempered Ductile Iron ◽  
Spur Gears ◽  
Reliability Design ◽  
Bending Fatigue ◽  
Bending Fatigue Strength ◽  
Number Of Cycles

Abstract An experimental evaluation of bending fatigue strength for austempered ductile iron (ADI) spur gears have been performed using Zwick fatigue tester. The gear material was manufactured by vertically continuous casting, in which the radius of the graphite grains is smaller. The Stress-Number of Cycles curve (S-N curve) for the bending fatigue strength of the ADI spur gears are manufactured without any specific surface treatments, and have been obtained by post-processing software. It was observed that when the reliability was 50%, the fatigue limit was 304.89 MPa. It has provided a reliable basis to rate the reliability design of the small gearboxes in automation later.

Determination of Fatigue Limit by Locati Methodusing S-N Curve Determined by Means of Thermographic Method

2014 ◽  
Vol 223 ◽  
pp. 362-373 ◽  
Author(s):  
Adam Lipski
Keyword(s):  
Fatigue Limit ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Fatigue Curve ◽  
Rotational Frequency ◽  
Automatic Equipment ◽  
Staircase Method ◽  
New Approach ◽  
Combined Application

Selected results of experimental research showing possibilities to combined accelerated methods, i.e. thermographic determination of the fatigue curve and estimating the fatigue limit, were presented in this paper. The tests were performed using the reversed bending fatigue-testing machine with a rotational frequency of 77 Hz. The main item of the test station was the thermographic camera. Test specimens were made of C45 (1.0503) steel drawn bars. The full tests results were presented for the fatigue S-N curve (23 specimens at 10 load levels) and fatigue limit by the Staircase method (25 specimens) based on 107 cycles to failure was determination. The accelerated test for determining the slope of the S-N curve and the fatigue limit were made by a single specimen based on gradually increasing loading. Methods previously presented in the literature are based on the phenomenon of temperature stabilization during most of the fatigue process. The results presented in this work did not show the occurrence of such a phenomenon. For that reason, the new approach to the determination of the slope of S-N curve was proposed. Combined application of both experimental methods, Locati and thermographic, with a new approach to the determination of this slope might allow one to develop automatic equipment for the accelerated determination of the fatigue limit which would contribute to significant reduction of the test costs and time, thus increasing availability of such tests.

scholarly journals Cyclic Fatigue Comparison of TruNatomy, Twisted File, and ProTaper Next Rotary Systems

2020 ◽  
Vol 2020 ◽  
pp. 1-4
Author(s):  
Abdullah Mahmoud Riyahi ◽  
Amr Bashiri ◽  
Khalid Alshahrani ◽  
Saad Alshahrani ◽  
Hadi M. Alamri ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Fatigue Resistance ◽  
Fatigue Testing ◽  
Clinical Performance ◽  
Cyclic Fatigue ◽  
Tooth Structure ◽  
Multiple Comparison Test ◽  
Continuous Rotation ◽  
Number Of Cycles ◽  
Cycles To Failure

TruNatomy (TN; Dentsply Sirona, Maillefer, Ballaigues, Switzerland) is a newly released system that was not tested in any previous studies. The objective of this work is to evaluate cyclic fatigue resistance of the new file and compare it with the Twisted Files (TF) and ProTaper Next (PTN). Forty-five files were distributed into 3 groups: PTN X2 (size 25 and taper 0.06), TF (size 25 and taper 0.06), and TN prime file (size 26 and taper 0.04). Each group included 15 files. Lengths of all files were 25 mm. Cyclic fatigue testing was done using artificial stainless-steel canals with 60-degree curvature and 5 mm radius. Continuous rotation movement at 300 rpm was used until the file fractures. Time for file separation was recorded in seconds. The number of cycles to failure (NCF) mean and standard deviation for each group was calculated. For statistical analysis of data, ANOVA and Tukey’s multiple comparison test were used. Mean and standard deviation (SD) of NCF were 259 ± 37.2, 521.67 ± 63.07 and 846.67 ± 37.16 for PTN, TF, and TN respectively. TN on average had significantly the highest NCF compared with PTN (p<0.05) and TF (p<0.05). TruNatomy file showed superior cyclic fatigue resistance. With its potential to preserve tooth structure, this file offers a good cyclic fatigue advantage. However, future studies are required to evaluate other properties of this file and to examine its clinical performance.

Very Long Life Fatigue Behavior of Bearing Steel AISI 52100

2005 ◽  
Vol 297-300 ◽  
pp. 1846-1851 ◽  
Author(s):  
Q.Y. Wang ◽  
Hong Yan Zhang ◽  
M.R. Sriraman ◽  
Shou Xin Li
Keyword(s):  
Fatigue Limit ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Testing Machine ◽  
Bearing Steel ◽  
Aisi 52100 ◽  
Steel Aisi ◽  
Reversed Loading ◽  
Long Life ◽  
Number Of Cycles

For many applications, the understanding of very long life fatigue in materials becomes extremely important. In this study, the fatigue behavior of bearing steel GCr15 (conforming to AISI 52100) at very high number of cycles has been examined. Experiments on hourglass specimens were conducted in air at room temperature, for fully reversed loading condition (R=-1), using a piezoelectric fatigue testing machine operating at a frequency of 20kHz. The results indicate that the S-N data does not reach a horizontal asymptote (signifying the fatigue limit) at 107 cycles, as conventionally believed, and that the material can fracture up to 109 cycles. Therefore, to quote a fatigue limit at 107 cycles may not hold good for the material studied. The influence of defects (such as inclusions) on the crack initiation and fracture was analyzed by scanning electron microscopy.

SnAgCu Micro-Ball Grid Array (BGA) Solder Joint Evaluation Using a Torsion Mechanical Fatigue Test Method

2005 ◽  
Author(s):  
Claire Ryan ◽  
Bryan A. Rodgers ◽  
Jeff M. Punch
Keyword(s):  
Fatigue Test ◽  
Solder Joints ◽  
Fatigue Testing ◽  
Ball Grid Array ◽  
Test Method ◽  
Superior Performance ◽  
Cycle Number ◽  
Mechanical Fatigue ◽  
Number Of Cycles ◽  
Cycles To Failure

Due to the hazard which lead poses to health and the environment the EU is banning its use in electrical and electronic equipment from July 2006. This ban along with the market drive to more environmentally friendly products means that tin-lead solders must be replaced with lead-free alternatives. This paper presents the results of an experimental investigation of the mechanical fatigue properties of tin-silver-copper (SnAgCu) solder joints with a baseline of tin-lead (SnPb). The test vehicle comprised of an 8-layer FR4 printed circuit board (PCB) mounted with four micro-ball grid array (BGA) components — each with a total of 100 solder balls in a 10×10 array. The solder joints were formed using surface mount reflow processes optimised for both solder types. A torsion mechanical fatigue test was employed to evaluate the solder joints — the principle of which was to stress the solder joints repetitively in order to determine the number of cycles to failure. The BGA components were daisy-chained — the resistance across each daisy-chain was monitored continuously during the cyclic defection of the test board. A profile of the increase in resistance with cycle number was established and the number of cycles to failure determined. The failure mechanism induced by the cycling was examined using cross-section and scanning electron microscopy (SEM) techniques. The results for SnAgCu joints show a superior performance during torsion mechanical fatigue testing than SnPb joints; giving a greater number of cycles to failure. The results from the tests presented in this paper show that the torsion test method provides a viable alternative to ATC as a qualification method for solder joints, while also providing substantial time savings — taking weeks rather than months to complete.

scholarly journals M. W. Tofique, A. Löf, C. Millward, Z. Günther. Testing and calculation of impact fatigue strength of Flap-X and SS 716 flapper valve steel grades / trans from Engl. M. A. Fedorova

2021 ◽  
Vol 5 (3) ◽  
pp. 63-74
Author(s):  
M. A. Fedorova ◽  
Keyword(s):  
Fatigue Strength ◽  
Service Life ◽  
Fluid Pressure ◽  
Test Method ◽  
Impact Fatigue ◽  
Staircase Test ◽  
Reliable Service ◽  
Steel Grades ◽  
Valve Steel ◽  
The Impact

During the operation of reciprocating compressors, the flapper valve opens and closes under fluid pressure and flow. As it closes, it strikes against the valve seat, generating stresses and noise. This cycle of loading produces bending and impact fatigue stresses in the reed. This load pattern is repeated billions of times during the service life of a compressor and it defines the service life and reliability. The goal of this study was to calculate the impact fatigue strength of the Flap-X and the SS 716 grades and, to provide the compressor manufacturers with the information they can use to specify a steel grade to be used in their compressors, for reliable service. Impact fatigue tests were conducted on a custom-built impact fatigue test rig that used air pulses to produce movement of the reed valves manufactured by a major European compressor manufacturer Nidec Global appliance GmbH, at a frequency of 315 Hz and pulse width of 2,2 milliseconds. The testing was conducted according to the staircase test method detailed in the International Standard SS-ISO 12107:2012. The impact fatigue strength of the Flap-X and SS 716 steel valves was calculated in terms of the impact velocity according to the modified staircase test method in the standard. The test results and their statistical analysis showed that the impact fatigue strength of the Flap-X grade was higher compared to the SS 716 grade. The calculation and testing of the impact fatigue strength of the flapper valve steel grades could help the compressor designers to select the optimum material for their compressor designs, to provide reliable service. The higher impact fatigue strength of the Flap-X grade, lower failure rate and longer impact fatigue life will allow the compressor manufacturers to design thinner valves, as Flap-X can sustain higher impact fatigue stresses reliably for longer time and, at the same time help reduce noise, as thinner valves produce less noise for a given pressure and frequency.

Study on Bending Ultrasonic Fatigue Behavior of Sinter-Hardened Fe-2Cu-2Ni-1Mo-1C Materials Prepared by Warm Compaction

2010 ◽  
Vol 638-642 ◽  
pp. 1848-1853 ◽  
Author(s):  
Zhi Yu Xiao ◽  
Ling Zhou ◽  
Yuan Xun Shen ◽  
Tungwai Leo Ngai ◽  
Yuan Yuan Li
Keyword(s):  
Fatigue Strength ◽  
Crack Propagation ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Bending Fatigue ◽  
Warm Compaction ◽  
Ultrasonic Fatigue ◽  
Number Of Cycles ◽  
Rupture Mode

Bending fatigue behavior of a sinter-hardened high density (7.4 g/cm3) Fe-2Cu-2Ni-1Mo-1C material fabricated by die-wall lubricated warm compaction of partially-diffuse alloyed powder was studied by bending ultrasonic fatigue testing. Results showed that fatigue strength decreases continuously with the increasing number of cycles. The fatigue failure yet occurs in the regime of exceeding 107 cycles and exhibits no traditional horizontal plateau between 106 and 107 cycles. Fatigue strength was 194 MPa, 239 MPa and 293 MPa at 108, 107 and 106 cycles respectively. Scanning electron microscopy revealed that cracks initiated from large pores on the surface and from pore clusters near the sub-surface. The fatigue cracks initiated both at single and multiple sites. Crack propagation was mainly in a trans-crystalline rupture mode. Fatigue striation and cleavage plane were observed in the crack propagation region and dimples were observed in the fracture zones.

Influence of Microstructure and Defect Population on the Fatigue Performance of Cast A356-T6 Automotive Components

2014 ◽  
Vol 782 ◽  
pp. 301-305
Author(s):  
Radomila Konečná ◽  
Gianni Nicoletto ◽  
Enrica Riva
Keyword(s):  
Fatigue Strength ◽  
Cylinder Head ◽  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
High Strength ◽  
Cycle Fatigue ◽  
Cast Aluminum ◽  
Staircase Method ◽  
Automotive Components ◽  
Aluminum Cylinder

In the paper fatigue specimens are extracted from different regions of cast aluminum cylinder heads produced by two foundries. A high strength region and a low strength region were identified within the cylinder head and the A356-T6 material locally characterized in terms of microstructure and defect population. High cycle fatigue testing according to a reduced staircase method was performed to determine the local fatigue strength at 107 cycles in the cylinder heads of the two foundries. The implications of the experimental observations are discussed.

Push-Pull Fatigue Strength of Mild Steel at Very High Frequencies of Stress Up to 100 kc/s

1965 ◽  
Vol 87 (4) ◽  
pp. 857-864 ◽  
Author(s):  
M. Kikukawa ◽  
K. Ohji ◽  
K. Ogura
Keyword(s):  
Fatigue Strength ◽  
Mild Steel ◽  
Fatigue Limit ◽  
Fatigue Testing ◽  
Low Frequency ◽  
Carbon Steels ◽  
High Frequencies ◽  
Very High Frequencies ◽  
Very High

Previous investigations of frequency on fatigue strength are briefly reviewed in this paper. New resonant-type push-pull fatigue testing machines at 50 and 100 kc/s were also developed by using a ferrite magnetostrictive vibrator. By using these machines, as well as previously developed high and low-frequency push-pull fatigue testing machines, the influence of stress frequency on fatigue limit of two carbon steels was determined at frequencies ranging from 40 to 100,000 c/s. The fatigue limit was found to increase monotonically with increasing frequency. No peak in the value of the fatigue limit was observed at frequencies up to 100,000 c/s.

scholarly journals Effect of Sandblasting on Static and Fatigue Strength of Flash Butt Welded 75Cr4 Bandsaw Blades

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6831
Author(s):  
Andrzej Kubit ◽  
Łukasz Lenart ◽  
Tomasz Trzepieciński ◽  
Andrzej Krzysiak ◽  
Wojciech Łabuński
Keyword(s):  
Standard Deviation ◽  
Fatigue Strength ◽  
Stress Amplitude ◽  
Load Capacity ◽  
Fatigue Cracks ◽  
Cold Work ◽  
Tensile Load ◽  
Test Material ◽  
Percentage Increase ◽  
Number Of Cycles

The aim of the research presented in this article is analysis of the effect of the surface treatment method on the static and fatigue strength of flash butt welded bandsaw blades. A 1-mm-thick 75Cr1 cold-work tool steel sheet used for bandsaw blades was used as the test material. Fractographic studies of the fatigue fractures and fractures formed in static tests were also carried out. The static strength tests showed sandblasting the weld surface had no significant effect on the load capacity of the joint. However, the sandblasted specimens showed a higher repeatability of the load capacity (lower standard deviation). In the case of both analyzed sample variants of specimens, sandblasted and non-sandblasted, the number of cycles at which the sample was damaged decreases with the percentage increase of the stress amplitude. When loading the samples with a stress amplitude value in the range between 400 and 690 MPa, sandblasting of the weld surface increased the average value of destructive cycles by about 10–86% (depending on the stress amplitude) compared to non-sandblasted joints. The sandblasting process introduces compressive stresses in the surface layer of the welds, therefore the variable tensile load acting on the sample requires a greater number of cycles before the fatigue cracks initiate and propagate. In the case of all specimens, a ductile fracture was observed. It was also found that, regardless of the variable stress amplitude, sandblasting has a positive effect on reducing the standard deviation of fatigue test results.

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