Dynamic Response and High Cycle Fatigue Analysis of Fan Blades under Inlet Distortion

2012 ◽  
Author(s):  
Georgios Doulgeris ◽  
Guillaume Lelias ◽  
Panagiotis Laskaridis ◽  
P. Pilidis ◽  
Riti Singh
Keyword(s):  
Dynamic Response ◽  
High Cycle Fatigue ◽  
Fatigue Analysis ◽  
Cycle Fatigue ◽  
Inlet Distortion

Deformation and Fatigue Analysis of Micro Thermal-Electrostatic Actuator Devices

Volume 3 ◽  
2004 ◽  
Author(s):  
Jeng-Nan Hung ◽  
Meng-Ju Lin ◽  
Chung-Li Hwan
Keyword(s):  
Applied Voltage ◽  
High Cycle Fatigue ◽  
Fatigue Analysis ◽  
Flexible Beam ◽  
Cycle Fatigue ◽  
Fatigue Cycle ◽  
Electrostatic Actuator ◽  
Beam Length ◽  
The Difference ◽  
Cold Arms

Micro thermal-electrostatic actuator devices are widely used in MEMS. However, the effect of structure sizes on deformation and fatigue is seldom discussed. In this work, the effect of structure sizes on deformation and fatigue is investigated. In this device, two beams called hot and cold arms with different width under applied voltage will have different elongation for there different width and the structure will cause the structure laterally bent. Theoretical solutions of deformation and stresses are derived. And numerical methods of finite element are used to analyze for details. The stresses obtained from the finite element are used in fatigue analysis. In the fatigue analysis, high-cycle fatigue model is used as the load in the elastic regime. Considering the accumulation of damage by fatigue being linear, Miner theory is used to estimate the life of the thermal-electrostatic devices under high-cycle fatigue. The result shows with the same length and flexible beam length connecting the hot and cold arms, the large width will cause larger displacement and stresses. However, the difference is not significant. It is also found that as the applied voltage increasing, the displacement and stresses will increase nonlinearly. With the same width and flexible beam length, the larger length will cause larger stresses and small displacement. For fatigue analysis, as the gap increasing and the length and width decreasing, the fatigue cycle increases. It shows when the length and gap are 220 and 5 μm, the fatigue cycle of 50 μm width is more than ten times of 90 μm width. When the width and gap are 50 and 5 μm, the fatigue cycle of 220 μm length is more than ten times of 260 μm length. When the length and width are 220 and 50 fatigue cycles of 50 μm width are more than ten times of 90 μm width, the difference of fatigue cycle between gap 9 and 5 μm is more than 10 times. However, the most significant effect on fatigue is the applied voltage. It shows the fatigue cycle decays very fast as the applied voltage increasing. When the applied voltages are 2 and 8 volts, the fatigue cycles will decrease from 1018 to less than 108. As the applied voltage being 25 volt, the fatigue cycle near zero. Therefore, the limit applied voltage is about 25 volt.

scholarly journals High cycle fatigue analysis in the presence of autofrettage compressive residual stress

2018 ◽  
Vol 41 (11) ◽  
pp. 2305-2320
Author(s):  
V. Okorokov ◽  
D. MacKenzie ◽  
Y. Gorash ◽  
M. Morgantini ◽  
R. van Rijswick ◽  
...  
Keyword(s):  
Residual Stress ◽  
Compressive Residual Stress ◽  
High Cycle Fatigue ◽  
Fatigue Analysis ◽  
Cycle Fatigue

Experimental Investigation of Vibration Damping Behavior of Magneto-Mechanical Coated AISI321 Stainless-Steel

2019 ◽  
Author(s):  
Hafiz Muhammad Ashraf ◽  
Farhan Ali
Keyword(s):  
Stainless Steel ◽  
Dynamic Response ◽  
High Speed ◽  
High Cycle Fatigue ◽  
Damping Ratio ◽  
Base Material ◽  
Rotating Machinery ◽  
Cycle Fatigue ◽  
Damping Characteristics ◽  
Aisi 321

Abstract High speed rotating machineries usually operate under severe conditions and enormous loadings and thus, are susceptible to several problems. One such problem that has caught the attention in recent decades is known as High Cycle Fatigue. More than 60 percent of rotating machinery failures has been attributed to this High cycle Fatigue. Along with High Cycle Fatigue, Vibration, an inherent phenomenon in machineries, also share its part in failure of rotating machineries. Rotating machinery components suffer from high amplitude vibrations when they pass through resonance. Stresses are developed as a result of these vibrations and fatigue in mechanical structures, providing a conducive environment for the development of cracks at Surface. When these surface cracks reach critical size, crack nucleation starts, which ultimately leads to catastrophic failures. So, in order to avoid the disastrous consequences, damping is needed. Damping keeps material’s integrity in case of impact forces, stresses due to thermal shocks in turbo machinery and earth quakes in huge structures. Thin layer of magneto elastic coating can be applied on substrate surface that acts as first line of defense. Large number of coating Processes are available around the globe. The optimized combination of coating material, substrate material and coating technique according to specific application is necessary. These coatings have the capability to combat the phenomenon of oxidation, wear and fatigue acting as a barrier between substrate and hostile environments. Further, they enhance the damping characteristics, and thus allows the high-speed rotating machinery to reach its operational speed without any failure at resonance. In this way, they not only enhance the performance of components in aggressive environments, but also improve the life cycle, saving assets of millions of dollars’ worth. This research is an endeavor to experimentally investigate effect of magneto mechanical coating on damping of AISI 321 Stainless steel. AISI 321 was selected as base material because of its wide applications in engine components of gas turbines, heat exchangers and in different chemical industries. Two types of Air plasma sprayed magneto-mechanical powder (NiAl & CoNiCrAlY) were coated on base material and thickness was maintained up to 250μm in both the cases. Experiments were designed and performed on cantilever beam specimens for dynamic response measurement. Dynamic response of the system was measured to investigate the modal parameters of natural frequencies, damping ratio and time of vibration decay. For damping ratio, vibration analyzer mode was adjusted in time domain and beam was excited by using a hammer. Vibration analyzer showed the vibration decay as a function of time. Logarithmic decrement method was used to calculate the damping ratio in both cases. Dynamic response of all the three cases (NiAl coating, CoNiCrAlY and uncoated AISI321) were compared. Results were very reassuring and showed a significant improvement in damping characteristics.

Experimental Investigation of Vibration Damping Behavior of Magneto-Mechanical Coated AISI321 Stainless-Steel

2020 ◽  
Author(s):  
Hafiz Muhammad Ashraf ◽  
Farhan Ali ◽  
Muhammad Imran Sadiq
Keyword(s):  
Stainless Steel ◽  
Dynamic Response ◽  
High Cycle Fatigue ◽  
Damping Ratio ◽  
Base Material ◽  
Rotating Machinery ◽  
Cycle Fatigue ◽  
Damping Characteristics ◽  
Aisi 321 ◽  
Rotating Machineries

Abstract High speed rotating machineries usually operate under severe conditions and enormous loadings and thus, are susceptible to several problems. One such problem that has caught the attention in recent decades is known as High Cycle Fatigue. More than 60 percent of rotating machinery failures has been attributed to this High cycle Fatigue. Along with High Cycle Fatigue, Vibration, an inherent phenomenon in machineries, also share its part in failure of rotating machineries. Rotating machinery components suffer from high amplitude vibrations when they pass through resonance. Stresses are developed as a result of these vibrations and fatigue in mechanical structures, providing a conducive environment for the development of cracks at Surface. When these surface cracks reach critical size, crack nucleation starts, which ultimately leads to catastrophic failures. So, in order to avoid the disastrous consequences, damping is needed. Damping keeps material’s integrity in case of impact forces, stresses due to thermal shocks in turbo machinery and earth quakes in huge structures. Thin layer of magneto elastic coating can be applied on substrate surface that acts as first line of defense. Large number of coating Processes are available around the globe. The optimized combination of coating material, substrate material and coating technique according to specific application is necessary. These coatings have the capability to combat the phenomenon of oxidation, wear and fatigue acting as a barrier between substrate and hostile environments. Further, they enhance the damping characteristics, and thus allows the highspeed rotating machinery to reach its operational speed without any failure at resonance. In this way, they not only enhance the performance of components in aggressive environments, but also improve the life cycle, saving assets of millions of dollars’ worth. This research is an endeavor to experimentally investigate effect of magneto mechanical coating on damping of AISI 321 Stainless steel. AISI 321 was selected as base material because of its wide applications in engine components of gas turbines, heat exchangers and in different chemical industries. Two types of Air plasma sprayed magneto-mechanical powder (NiAl & CoNiCrAlY) were coated on base material and thickness was maintained up to 250μm in both the cases. Experiments were designed and performed on cantilever beam specimens for dynamic response measurement. Dynamic response of the system was measured to investigate the modal parameters of natural frequencies, damping ratio and time of vibration decay. For damping ratio, vibration analyzer mode was adjusted in time domain and beam was excited by using a hammer. Vibration analyzer showed the vibration decay as a function of time. Logarithmic decrement method was used to calculate the damping ratio in both cases. Dynamic response of all the three cases (NiAl coating, CoNiCrAlY and uncoated AISI321) were compared. Results were very reassuring and showed a significant improvement in damping characteristics.

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