The Impact Response Characteristics Research of the Multilayer Structure, Cantilever-Type Electrothermal Actuator Based on MEMS

2014 ◽  
Vol 901 ◽  
pp. 87-92
Author(s):  
Ya He Wang ◽  
Yue Yue Shen ◽  
Chao Lv
Keyword(s):  
Multilayer Structure ◽  
Fem Simulation ◽  
Impact Response ◽  
Von Mises Stress ◽  
Beam Model ◽  
The Finite Element Method ◽  
Response Characteristics ◽  
Von Mises ◽  
Fixed End ◽  
The Impact

To study the impact response characteristics of multilayer structure, cantilever-type electrothermal actuators based on MEMS, a composite cantilever-beam model consisting of two layers of materials, SiO2 and Al, is built. By using the engineer mechanics theory, the von mise stress under the impacts in the fuze system can be obtained. Meanwhile, the Finite Element Method (FEM) simulation is made to get the deformation displacement of the fixed end and the von mises stress distribution of the model. Besides, the natural frequency response is studied. The results present the actuators response characteristics of impacts in the fuze system.

A Study on Bird Impact Damages on Shrouded Fan Blades of an Aero-Engine

2013 ◽  
Author(s):  
Raghu Prakash ◽  
Hithesh Channegowda ◽  
Anandavel Kaliyaperumal
Keyword(s):  
Plastic Strain ◽  
Impact Resistance ◽  
Three Dimensional ◽  
Impact Response ◽  
Von Mises Stress ◽  
Aero Engine ◽  
Bird Impact ◽  
Critical Components ◽  
Von Mises ◽  
The Impact

Aero-engine fan blades are the critical components that are vulnerable to Foreign Object Damage (FOD) such as bird impact. The thrust loss due to bird impact can affect engine core function, resulting in catastrophic failure. The fan blades should be designed to have adequate resistance to bird impact. The present paper focuses on numerical evaluation of bird impact response on shrouded and un-shrouded rotating set of fan blades using three dimensional computational methodology. The impact response is compared between shrouded and un-shrouded blades in terms of deformation, von-Mises stress, plastic strain, and energy absorbed. Numerical analysis results indicate that the shrouded fan blade absorbs 35 % more energy compared to un-shrouded blade. Deformation damage at impact location of shrouded blade is lesser compared to un-shrouded blade. The maximum plastic strain observed on shrouded blade due to bird impact is also 50 % lesser than the un-shrouded blade. The study suggests that the shrouded fan blades provide better impact resistance characteristics to bird impact compared to un-shrouded fan blades.

The Adaptive Blade Design and Evaluation of Wind Turbine

2010 ◽  
Vol 97-101 ◽  
pp. 2318-2323
Author(s):  
Wang Yu Liu ◽  
Jia Xing Gong ◽  
Xi Feng Liu ◽  
Xin Zhang
Keyword(s):  
Wind Turbine ◽  
Medial Axis ◽  
Coupling Effect ◽  
Design Method ◽  
Von Mises Stress ◽  
Blade Design ◽  
Adaptive Performance ◽  
Laminar Shear Stress ◽  
Von Mises ◽  
The Impact

This article explored the design method of the wind turbine blade being of flapping-twist adaptive performance and how to evaluate its feasibility and reliability according to the comprehensive factors. The results indicate that both spar cap and skin with off-axis carbon fiber can achieve the efficient flapping-twist coupling effect. Through overall investigation, the results show that the maximum fiber strains of tensile and compressive go up with increase of the off-axis angle, and the peak inter-laminar shear stress increase more rapidly. While, all of these evaluating indicators should be kept in the reference range for used materials. Moreover, when the off-axis angle increases, the peak Von Mises stress declines. In addition, the impact of natural frequencies on the blade design is proved to be insignificant. Finally, utilizing the medial axis laminates in the blade decoupled area is helpful to strengthen the blade fatigue resistivity.

Examination of the Stress Distribution in the Tip of a Pencil

2005 ◽  
Vol 73 (2) ◽  
pp. 335-337
Author(s):  
E. Pogozelski ◽  
D. Cole ◽  
M. Wesley
Keyword(s):  
Stress Distribution ◽  
Fracture Surface ◽  
Initial Position ◽  
Von Mises Stress ◽  
Shear Stresses ◽  
Worst Case ◽  
Position And Orientation ◽  
Von Mises ◽  
The Impact ◽  
Normal And Shear Stresses

The stresses within the tip of a pencil are examined theoretically, numerically, and experimentally to determine the position and orientation of the fracture surface. The von Mises stress is used to evaluate the impact of the normal and shear stresses due to compression, bending, torsion, and shear. The worst-case stress is shown to occur along the top edge of the inclined pencil point, where the normal stress is compressive. The resulting crack propagates diagonally downwards and towards the tip from this initial position, and is frequently observed to contain a cusp.

ANALYSIS OF THE MECHANICAL STATE OF THE HUMAN KNEE JOINT WITH DEFECT CARTILAGE IN STANDING

2016 ◽  
Vol 16 (08) ◽  
pp. 1640021 ◽  
Author(s):  
LULU QIU ◽  
XUEMEI MA ◽  
LILAN GAO ◽  
YUTAO MEN ◽  
CHUNQIU ZHANG
Keyword(s):  
Knee Joint ◽  
Weight Bearing ◽  
Von Mises Stress ◽  
The Finite Element Method ◽  
Human Knee ◽  
Femoral Cartilage ◽  
Human Knee Joint ◽  
Increasing Trend ◽  
Lower Limb Movement ◽  
Von Mises

Knee joint is the hub of human lower limb movement and it is also an important weight-bearing joint, which has the characteristics of load-bearing and heavy physical activities. So the knee joint becomes the predilection site of clinical disease. Once people have the cartilage lesions, their daily life will be affected seriously. The simulation of the knee joint lesions could provide help for clinical knee-joint treatment. Based on the complete model of knee joint, this paper use the finite element method to analyze the biomechanical characteristics of the defective knee joint. The results of simulation show that the stress of cartilages when standing on single leg is approximately doubled than that of standing on two legs. When standing on single leg, the 8-mm diameter osteochondral defect in femur cartilage can generate maximal changes in von-mises stress (by 36.74%), while the von-mises stress on tibia cartilage with 8-mm defect increase by 87%. The stress distribution of cartilages is almost the same, there is no obvious stress concentration when in defect. Increasing the defective diameter, femoral cartilage, meniscus and tibial all present an increasing trend towards stress. When increasing the applied load, the stress of the femoral cartilage, the meniscus and the tibial cartilage all increased.

scholarly journals Design, Analysis and Fabrication of High Clearance Self- Propelled Foliar Applicator

2020 ◽  
pp. 367-378
Author(s):  
Pankaj Malkani ◽  
Sunil Kumar Rathod ◽  
K. R. Asha ◽  
Tapan Kumar Khura ◽  
H. L. Khuswaha
Keyword(s):  
Computer Aided Design ◽  
Simulation Analysis ◽  
Foliar Application ◽  
Nutrient Use Efficiency ◽  
Fem Simulation ◽  
Von Mises Stress ◽  
Maximum Deformation ◽  
Nutrient Use ◽  
Von Mises ◽  
Aided Design

In this paper Finite element method (FEM) for design and development of self- propelled foliar applicator is presented. Foliar application is a method for feeding nutrients directly to plants for enhancing nutrient use efficiency through foliar applicator. The major components of the foliar applicator were engine (3.5 kW), gearbox (4F+1R), chassis (1.2 x 0.96 m2), sub-frame assembly, spraying diaphragm pump (Model-SFWP1-055-070-31, capacity 20 lm-1 at 4.4 bar), fertilizer storage tank (225 l). The main objective of this FEM simulation analysis is to find out the stress, deformation and strain induced in chassis and sub-frame assembly of foliar applicator for given boundary condition.  A Computer Aided Design of foliar applicator was developed using Creo-parametric 1 software and then analyzed in FEM mode by using Creo simulation1 software. FEM static analysis resulted in maximum von mises stress 200.750MPa and182.638MPa, maximum deformation 2.81 mm and 1.29 mm and max strain 0.001047 and 0.000636 for chassis and sub-frame assembly respectively. Maximum stresses in both didn’t exceed the respective yield points which signified designs, can be used for fabrication.

scholarly journals Experimental Investigations of Offshore Sand Production Monitoring Based on the Analysis of Vibration in Response to Weak Shocks

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Yichen Li ◽  
Gang Liu ◽  
Zongwen Jia ◽  
Min Qin ◽  
Gang Wang ◽  
...  
Keyword(s):  
Pipe Wall ◽  
Oil Wells ◽  
Impact Response ◽  
Sand Production ◽  
Time Frequency ◽  
Response Characteristics ◽  
Sand Particles ◽  
Production Monitoring ◽  
Offshore Oil ◽  
The Impact

Sand production is a problem that is often encountered in unconventional oil and gas exploitation and that is difficult to effectively solve. Accurate online monitoring of sand production is one of the keys to ensuring the safety and long-term production of oil wells as well as efficient production throughout the life cycle of production wells. This paper proposes a method for monitoring sand production in offshore oil wells that is based on the vibration response characteristics of sand-carrying fluid flow impinging on the pipe wall. This method uses acceleration sensors to obtain the weak vibration response characteristics of sand particles impinging on the pipe wall on a two-dimensional time-frequency plane. The time-frequency parameters are further optimized, and the ability to identify weakly excited vibration signals of sand particles in the fluid stream is enhanced. The difference between the impact response of the sand particles and the impact response of the fluid flow to the pipe wall is identified, and corresponding indoor verification experiments are carried out. Under different sand contents, particle sizes, and flow rates (sand content 0-2‰, sand particle size 96-212 μm, and flow velocity 1-3 m/s), the impact response frequency of sand particles to the pipe wall exhibits good consistency. The characteristic frequency band of sand impacting the pipe wall is 30-50 kHz. A statistical method is used to establish the response law of the noise signal of the fluid. Based on this knowledge, a real-time calculation model of sand production in offshore oil wells is constructed, and the effectiveness of this model is verified. Finally, a field test is carried out with a self-developed sand production signal dynamic time-frequency response software system on 4 wells of an oil production platform in the Bohai Sea. This system can effectively distinguish sand-producing wells from non-sand-producing wells. The dynamic time-frequency response, field test results, and actual laboratory results are consistent, verifying the effectiveness of the method proposed in this paper and further providing a theory for improving the effectiveness of the sand production monitoring method under complex multiphase flow conditions. This study also provides technical guidance for the industrial application of sand production monitoring devices in offshore oil wells.

Investigation of Meniscus Effect on Microbond Test of Typha Fiber/Epoxy Matrix

2020 ◽  
Vol 402 ◽  
pp. 14-19
Author(s):  
Andri Afrizal ◽  
Ikramullah ◽  
Syarizal Fonna ◽  
Syifaul Huzni
Keyword(s):  
Epoxy Matrix ◽  
Maximum Stress ◽  
Interfacial Shear Strength ◽  
Von Mises Stress ◽  
Microbond Test ◽  
The Matrix ◽  
The Difference ◽  
Von Mises ◽  
The Impact ◽  
Fiber Radius

The microbond test was one of the methods to examine the interfacial shear strength (IFSS) value of fiber and polymer matrix. The meniscus angle that formed at both ends of the matrix is difficult to control while manufacturing the specimen for the microbond test. Therefore, the effect of meniscus angle must be evaluated. In this paper, we evaluated the impact of variations of the meniscus angle against the maximum von-mises stress and the IFSS value of the Typha fiber epoxy matrix by finite element method. The geometry of the microbond test specimen was modeled with 0.25 mm fiber radius, 2 mm fiber length, 1.75 mm embedded length of the matrix, and varied the meniscus angles with 22°, 30°, 45°, 60°, 75°, and 90°. The mesh type quad-dominated CAX4R is used on fiber and matrix, while quad COHAX4 is applied to the cohesive element between fiber and matrix. The constantly applied displacement was adjusted to the upper end of the fiber at 0.6 mm. The simulation results showed that the difference in maximum stress obtained in each model. Furthermore, that is not given much difference in IFSS value. It can be concluded that the meniscus angle affects the maximum von-mises stress but not too much-affected IFSS value of the fiber and epoxy matrix.

scholarly journals Multi-layered bird beaks: a finite-element approach towards the role of keratin in stress dissipation

2012 ◽  
Vol 9 (73) ◽  
pp. 1787-1796 ◽  
Author(s):  
Joris Soons ◽  
Anthony Herrel ◽  
Annelies Genbrugge ◽  
Dominique Adriaens ◽  
Peter Aerts ◽  
...  
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Speckle Pattern ◽  
Young Modulus ◽  
Von Mises Stress ◽  
Fe Model ◽  
Element Approach ◽  
Von Mises ◽  
The Impact

Bird beaks are layered structures, which contain a bony core and an outer keratin layer. The elastic moduli of this bone and keratin were obtained in a previous study. However, the mechanical role and interaction of both materials in stress dissipation during seed crushing remain unknown. In this paper, a multi-layered finite-element (FE) model of the Java finch's upper beak ( Padda oryzivora ) is established. Validation measurements are conducted using in vivo bite forces and by comparing the displacements with those obtained by digital speckle pattern interferometry. Next, the Young modulus of bone and keratin in this FE model was optimized in order to obtain the smallest peak von Mises stress in the upper beak. To do so, we created a surrogate model, which also allows us to study the impact of changing material properties of both tissues on the peak stresses. The theoretically best values for both moduli in the Java finch are retrieved and correspond well with previous experimentally obtained values, suggesting that material properties are tuned to the mechanical demands imposed during seed crushing.

scholarly journals Effects of Shroud Curvature on the Performance of Centrifugal Compressor Blade

2011 ◽  
Vol 2-3 ◽  
pp. 700-705
Author(s):  
Kai Yuan Hao ◽  
Wei Min Wang ◽  
Yong Qiang Shi ◽  
Sha Sha Wang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Axial Length ◽  
Mechanical Analysis ◽  
Von Mises Stress ◽  
Centrifugal Impeller ◽  
Finite Element Analyses ◽  
Computational Fluid Dynamics Cfd ◽  
Von Mises ◽  
The Impact

The purpose of the study described in this paper was to investigate the impact of shroud curvature on the performance of a centrifugal impeller or stage. The paper discusses a computational fluid dynamics (CFD) study done to assess the influence of shroud curvature on impeller performance. The computational fluid dynamics (CFD) and finite element analyses (FEA) methods were used to describe the various designs of the impeller. Aerodynamic and mechanical analysis results are presented for four impellers of varying cover curvature and axial length. The aerodynamic results showed there were clear aerodynamic benefits to decreasing the curvature along the impeller shroud. The mechanical analytical results showed that the impeller with the lowest curvature or longest axial length provided the highest performance; it also yielded the lowest Von Mises stress level. In closing, there are clear aerodynamic benefits to decreasing the curvature along the impeller shroud but these benefits must be weighed against the impact on the rotordynamic considerations Comments are offered regarding the rotordynamic issues that must be considered when increasing the length of impellers.

The Design and Analysis of Universal Inertial Switch Based MEMS

2012 ◽  
Vol 157-158 ◽  
pp. 308-311
Author(s):  
Yong Ping Hao ◽  
Li Ya Bao ◽  
Shuang Xi Gu
Keyword(s):  
Response Time ◽  
High Speed ◽  
Maximum Stress ◽  
Von Mises Stress ◽  
Inertial Switch ◽  
Von Mises ◽  
Continuous Power ◽  
The Impact ◽  
Fast Acting ◽  
Speed Response

In this paper, a novel MEMS inertial switch is designed and characterized for the purpose of crash sensing for ammunition systems in which high-speed response is required for triggering the detonator. In order to keep the same sensitivity in different direction, the structure of an annular proof-mass suspended by four serpentine flexures is designed. The switch can be integrated with electronics, fast-acting，and lack of a requirement for continuous power, and can be used in a wide area. The motion of the inertial switch is analyzed by dynamic simulation under the 700g threshold acceleration in y direction, the simulation results show that the response time is 0.142ms and the contact time of the switch is about 5 , it illustrates that the response time is short enough and the impact time satisfy the ask. The von-mises stress of the structure is calculate, the maximum stress occurs in the serpentine flexures, the value is 60.61 MPa, much less than the yield strength of the silicon, the switch can be used time after time.

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