scholarly journals Evaluation of a Novel Condition Indicator with Comparative Application to Hypoid Gear Failures

2021 ◽  
Vol 11 (23) ◽  
pp. 11499
Author(s):  
Marcell Surányi ◽  
Michael Leighton ◽  
Christian Reinbrecht ◽  
Michael Bader
Keyword(s):  
Condition Monitoring ◽  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
Signal To Noise Ratio ◽  
Hypoid Gear ◽  
Cycle Fatigue ◽  
Signal To Noise ◽  
Hypoid Gears ◽  
Condition Indicator

This paper presents a condition monitoring methodology that uses a novel condition indicator (CI) algorithm, allowing for a confident assessment of system health and an advanced warning of failures. The CI is evaluated in the application of a specialized gear rig utilized for the high-cycle fatigue testing of hypoid gears. The CI is shown in this case study to ensure higher confidence in the prediction of failures than other algorithms, with variations in the results. In the comparison, consideration is given to the signal-to-noise ratio, the ability to differentiate between damages and/or damaged components and the sensitivity of the CI to the failure.

scholarly journals Collecting Microplastics in Gardens: Case Study (i) of Soil

2021 ◽  
Vol 9 ◽  
Author(s):  
Zahra Sobhani ◽  
Yunlong Luo ◽  
Christopher T. Gibson ◽  
Youhong Tang ◽  
Ravi Naidu ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Point Of View ◽  
Signal To Noise ◽  
Statistical Point ◽  
Image Mapping ◽  
Noise Ratio ◽  
In The Beginning ◽  
Raman Image ◽  
Selection Of

As an emerging contaminant, microplastic is receiving increasing attention. However, the contamination source is not fully known, and new sources are still being identified. Herewith, we report that microplastics can be found in our gardens, either due to the wrongdoing of leaving plastic bubble wraps to be mixed with mulches or due to the use of plastic landscape fabrics in the mulch bed. In the beginning, they were of large sizes, such as > 5 mm. However, after 7 years in the garden, owing to natural degradation, weathering, or abrasion, microplastics are released. We categorize the plastic fragments into different groups, 5 mm–0.75 mm, 0.75 mm–100 μm, and 100–0.8 μm, using filters such as kitchenware, meaning we can collect microplastics in our gardens by ourselves. We then characterized the plastics using Raman image mapping and a logic-based algorithm to increase the signal-to-noise ratio and the image certainty. This is because the signal-to-noise ratio from a single Raman spectrum, or even from an individual peak, is significantly less than that from a spectrum matrix of Raman mapping (such as 1 vs. 50 × 50) that contains 2,500 spectra, from the statistical point of view. From the 10 g soil we sampled, we could detect the microplastics, including large (5 mm–100 μm) fragments and small (<100 μm) ones, suggesting the degradation fate of plastics in the gardens. Overall, these results warn us that we must be careful when we do gardening, including selection of plastic items for gardens.

scholarly journals QT steel High Cycle Fatigue Testing with Ultrasonic

2017 ◽  
Vol 50 (3) ◽  
pp. 304-308 ◽  
Author(s):  
Jussi Korhonen ◽  
Juha Kuoppala ◽  
Miikka Väntänen ◽  
Joona Vaara ◽  
Mikko Turunen ◽  
...  
Keyword(s):  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
Cycle Fatigue

This article describes the fatigue testing of QT steel in ultrasonic frequencies. Different possibilities, challenges and prejudices are reviewed.

Influence of Reinforcement Geometry on the Very High-Cycle Fatigue Behavior of Aluminium-Matrix-Composites

2015 ◽  
Vol 825-826 ◽  
pp. 150-157 ◽  
Author(s):  
Alexandra Müller ◽  
Anja Weidner ◽  
Horst Biermann
Keyword(s):  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Aluminum Matrix ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Loading Conditions ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Very High

During technical operation, high performance materials are partially exposed to high frequency cyclic loading conditions. Furthermore, the small strains in the very high cycle fatigue (VHCF)-regime lead to accumulative damage which causes crack initiation related to an appropriate local deformation leading to final fatal fracture. At the same time, quite high requirements with regard to high number of cycles without any damage are demanded for many applications. Fields of application of these light-weight, but expensive materials, are e.g. in the automobile industry (e.g. engine blocks, cylinder heads, brakes).The fatigue behavior of Al-matrix composites (Al-MMCs) reinforced by alumina particles (15 vol.% Al2O3) or short fibers (20 vol.% Saffil), respectively, was already intensively studied in the LCF and HCF range. The present study is focusing on investigations in the very high cycle fatigue regime at stress amplitudes up to 140 MPa to reach fatigue life of about 1010 cycles. All experiments were carried out using an ultrasonic fatigue testing device under symmetric loading conditions (R=-1). Fatigue tests were accompanied by in situ thermography measurements to record the temperature of the whole specimen and to find “hot spots” indicating changes in microstructure and therefore the initiation or growth of cracks. Moreover, the resonant frequency as well as the damage parameter were evaluated to determine the beginning of damage. For a better understanding of the damage mechanism (matrix decohesion, matrix failure or failure of reinforcement) all fractured surfaces were investigated by scanning electron microscopy. The combination of these methods contributes to a better understanding of the underlying mechanism of damage in aluminum-matrix-composites.

Very High Cycle Fatigue Testing under Spectrum Loading for Endurance Limit Structural Design

2020 ◽  
Vol 65 (1) ◽  
pp. 1-7
Author(s):  
David T. Rusk ◽  
Robert E. Taylor ◽  
Bruce A. Pregger ◽  
Luis J. Sanchez
Keyword(s):  
Fatigue Test ◽  
Test Data ◽  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
Crack Nucleation ◽  
Peak Stress ◽  
Material Behavior ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Very High

A program has recently concluded that generated fatigue test data for the influence of a rotorcraft main rotor blade root bending spectrum (Helix) on the crack nucleation mechanisms in 7075-T651 aluminum. High-frequency tests were performed that generated spectrum fatigue failures out to nearly 109 cycles. Fractographic examination showed a distinct change in crack nucleation from slip initiated to inclusion-initiated cracking as the spectrum peak stress level was increased. Spectrum life predictions were made using three different baseline constant-amplitude S-N curves, one using a traditional rotorcraft original equipment manufacturer fitting methodology, one using the high-cycle fatigue (HCF) portion of a strainlife curve, and one that was fitted to S-N data with test lives out to 3×108 cycles. The spectrum life prediction using the S-N curve that properly modeled material behavior in the very high cycle fatigue regime provided a good correlation to the spectrum fatigue test data. Predictions using the other S-N curves were highly conservative.

scholarly journals Recent Advances in Very High Cycle Fatigue Behavior of Metals and Alloys—A Review

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1200
Author(s):  
Ashutosh Sharma ◽  
Min Chul Oh ◽  
Byungmin Ahn
Keyword(s):  
Crack Initiation ◽  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Simulation Studies ◽  
Cycle Fatigue ◽  
Future Directions ◽  
Very High Cycle Fatigue ◽  
Ultrasonic Fatigue ◽  
Very High

We reviewed the research and developments in the field of fatigue failure, focusing on very-high cycle fatigue (VHCF) of metals, alloys, and steels. We also discussed ultrasonic fatigue testing, historical relevance, major testing principles, and equipment. The VHCF behavior of Al, Mg, Ni, Ti, and various types of steels were analyzed. Furthermore, we highlighted the major defects, crack initiation sites, fatigue models, and simulation studies to understand the crack development in VHCF regimes. Finally, we reviewed the details regarding various issues and challenges in the field of VHCF for engineering metals and identified future directions in this area.

scholarly journals Fatigue life time modelling of Cu and Au fine wires

2018 ◽  
Vol 165 ◽  
pp. 06002
Author(s):  
Golta Khatibi ◽  
Ali Mazloum-Nejadari ◽  
Martin Lederer ◽  
Mitra Delshadmanesh ◽  
Bernhard Czerny
Keyword(s):  
Fatigue Life ◽  
Strain Rate ◽  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
Load Ratio ◽  
Life Time ◽  
Material Model ◽  
Cycle Fatigue ◽  
Rate Dependency

In this study, the influence of microstructure on the cyclic behaviour and lifetime of Cu and Au wires with diameters of 25μm in the low and high cycle fatigue regimes was investigated. Low cycle fatigue (LCF) tests were conducted with a load ratio of 0.1 and a strain rate of ~2e-4. An ultrasonic resonance fatigue testing system working at 20 kHz was used to obtain lifetime curves under symmetrical loading conditions up to very high cycle regime (VHCF). In order to obtain a total fatigue life model covering the low to high cycle regime of the thin wires by considering the effects of mean stress, a four parameter lifetime model is proposed. The effect of testing frequency on high cycle fatigue data of Cu is discussed based on analysis of strain rate dependency of the tensile properties with the help of the material model proposed by Johnson and Cook.

High-Cycle Fatigue and Thermal Dissipation Investigations for Low Carbon Steel Q345

2015 ◽  
Vol 664 ◽  
pp. 305-313 ◽  
Author(s):  
Han Qing Liu ◽  
Qing Yuan Wang ◽  
Zhi Yong Huang ◽  
Zhen Jie Teng
Keyword(s):  
Carbon Steel ◽  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
Low Carbon Steel ◽  
Infrared Camera ◽  
Fatigue Property ◽  
Thermal Dissipation ◽  
Loading Frequency ◽  
Cycle Fatigue ◽  
Low Carbon

Carbon steel is a kind of metallic material that widely used in construction, machinery, manufacturing and other domains. In the mechanical structure system, long-term cyclic stress may cause the mechanical components failure. In this work, the characteristic of fatigue crack propagate in low carbon steel Q345 and the effect of loading frequency to the fatigue property of Q345 steel were investigated. Meanwhile, the dispersion of high-cycle fatigue of life of the Q345 steel under high fatigue testing frequency was analyzed, and the P-S-N curve with the test data was given out. With the help of infrared camera, temperature rise curve during fatigue test was analyzed to study the thermal dissipation of Q345 steel.

Very high cycle fatigue testing of concrete using ultrasonic cycling

2017 ◽  
Vol 59 (5) ◽  
pp. 438-444 ◽  
Author(s):  
Ulrike Karr ◽  
Reinhard Schuller ◽  
Michael Fitzka ◽  
Andreas Denk ◽  
Alfred Strauss ◽  
...  
Keyword(s):  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Very High

Synchronous Analysis in Wind Turbine Gearbox Condition Monitoring

2012 ◽  
Author(s):  
Huageng Luo ◽  
Mingqi Luo ◽  
Shaobo Zhang
Keyword(s):  
Wind Turbine ◽  
Condition Monitoring ◽  
Signal To Noise Ratio ◽  
Sampling Technique ◽  
Signal To Noise ◽  
High Count ◽  
Wind Turbine Gearbox ◽  
Synchronous Sampling ◽  
Accuracy And Precision ◽  
Bearing Damage

This paper summarizes the application of “synchronous sampling” technique in the digital domain to enhance the signal-to-noise ratio in detection of wind turbine gear and bearing damage signatures. In this technique, only a once-per-revolution Key Phaser or a low-count Encoder signal is required. High-count synchronous sampling is achieved by resampling in the digital domain. Implementation and demonstration of the aforementioned techniques are illustrated in two current wind turbine field operation examples. The improvement in the accuracy and precision of damage feature extractions is demonstrated.

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