Dynamic Analysis of a Motion Transformer Mimicking a Hula Hoop

2009 ◽  
Author(s):  
C. X. Lu ◽  
C. C. Wang ◽  
C. K. Sung ◽  
Paul C. P. Chao
Keyword(s):  
Dynamic Analysis ◽  
Homotopy Perturbation Method ◽  
The Body ◽  
Energy Scavenging ◽  
Electric Circuits ◽  
Main Mass ◽  
Transformer Design ◽  
Varied System ◽  
Steady State Solutions ◽  
Lagrange’S Method

Hula-hoop motion refers to the spinning of a ring around a human body; it is made possible by the interactive force between the moving ring and the body. Inspired by the generic concept of hula-hoop motion, this study proposes a novel motion transformer design that consists of a main mass sprung in one translational direction and a free-moving mass attached at one end of a rod, the other end of which is hinged onto the center of the main mass. It is expected that the transformer is capable of transforming linear reciprocating motion into rotational motion. In addition, the transformer could be integrated with coils, magnets, and electric circuits to form a portable energy scavenging device. A thorough dynamic analysis of the proposed transformer system is conducted in this study in order to characterize the relationships between the varied system parameters and the chance of hula-hoop motion occurrence. The governing equations are first derived by using Lagrange’s Method, which is followed by the search for steady-state solutions and the corresponding stability analysis via the homotopy perturbation method and Floquet theory. Direct numerical simulation is simultaneously performed to verify the correctness of the approximate analysis. In this manner, the feasibility of the proposed design and the occurrence criteria of hula-hoop motion are assessed.

Dynamic Analysis of a Motion Transformer Mimicking a Hula Hoop

2011 ◽  
Vol 133 (1) ◽  
Author(s):  
C. X. Lu ◽  
C. C. Wang ◽  
C. K. Sung ◽  
Paul C.P. Chao
Keyword(s):  
Dynamic Analysis ◽  
Homotopy Perturbation Method ◽  
The Body ◽  
Energy Scavenging ◽  
Electric Circuits ◽  
Main Mass ◽  
Transformer Design ◽  
Varied System ◽  
Steady State Solutions ◽  
Lagrange’S Method

Hula-hoop motion refers to the spinning of a ring around a human body; it is made possible by the interactive force between the moving ring and the body. Inspired by the generic concept of hula-hoop motion, this study proposes a novel motion transformer design that consists of a main mass sprung in one translational direction and a free-moving mass attached at one end of a rod, the other end of which is hinged onto the center of the main mass. It is expected that the transformer is capable of transforming linear reciprocating motion into rotational motion. In addition, the transformer could be integrated with coils, magnets, and electric circuits to form a portable energy scavenging device. A thorough dynamic analysis of the proposed transformer system is conducted in this study in order to characterize the relationships between the varied system parameters and the chance of hula-hoop motion occurrence. The governing equations are first derived with Lagrange’s method, which is followed by the search for steady-state solutions and the corresponding stability analysis via the homotopy perturbation method and the Floquet theory. Direct numerical simulation is simultaneously performed to verify the correctness of the approximate analysis. In this manner, the feasibility of the proposed design and the occurrence criteria of hula-hoop motion are assessed.

Dynamic Analysis of a Hula-Hoop System

2010 ◽  
Author(s):  
C. H. Lu ◽  
C. K. Sung
Keyword(s):  
Dynamic Analysis ◽  
Homotopy Perturbation Method ◽  
Approximate Solutions ◽  
Reciprocating Motion ◽  
Main Mass ◽  
Homotopy Perturbation ◽  
Proposed Model ◽  
Steady State Solutions ◽  
Experimental Rig ◽  
Good Agreement

This paper presents a theoretical and experimental study into the dynamics of a hula-hoop system, in which a free-rotating mass mimicking the ring is hinged on a main mass that simulates the human body and performs translational reciprocating motion under external excitations. The physical model of the hula-hoop system was first constructed and the equations governing the motions of the main mass and the free-rotating mass were, then, derived. The approximate steady-state solutions were obtained by employing homotopy perturbation method and the stabilities of which were analyzed by using Floquet theory. Good agreement between the results obtained from stability analysis and numerical simulation implied that the approximate solutions were adequate for the dynamic analysis of the proposed model. Finally, an experimental rig consisting of a semicircular thin plate hinged on the top of a linear-motor stage was devised to mimic the hula-hoop motion based on the analytical analysis.

Dynamic Analysis of Hula Hoop Motion and Optimized Energy Harvest Circuit

2013 ◽  
Author(s):  
T.-C. Huang ◽  
W.-D. Chen ◽  
C. X. Lu ◽  
Paul C.-P. Chao ◽  
C.-H. Tsai ◽  
...  
Keyword(s):  
Dynamic Analysis ◽  
Experimental System ◽  
Force Balance ◽  
Asymptotic Solutions ◽  
Energy Harvest ◽  
Energy Scavenging ◽  
The Novel ◽  
Electric Circuits ◽  
Nonlinear Solutions ◽  
Nonlinear Dynamic Modeling

The nonlinear dynamics of hula hoop motion is deciphered in this study by nonlinear dynamic modeling techniques to find solution and stability analysis. This is different from the previous study [1], where a homotopy method is employed. The analysis results are capable of transforming linear reciprocating motion into rotational motion. The dynamic governing equations of the system are first successfully derived by force balance. The non-linear dynamic analysis is next applied to derive approximate, asymptotic solutions. Stabilities associated with all solution are determined by subsequent analysis on the derived asymptotic solutions. In addition, the transformer could be integrated with coils, magnets, and electric circuits to form a portable energy scavenging device. A novel front-end circuit is proposed in this work for harvesting human’s energy. The situation of human’s walking and running is simulated by a shaker. And the ac-like energy is processed by the novel energy harvesting circuit, transformed as a DC voltage suitable for devices successfully. The efficiency of the entire circuit is proven up to 60%, and is an input-powered circuit with no standby power. A complete experimental system is also designed and successfully confirm the existence of the stable nonlinear solutions found by analytical and numerical analysis.

EPIDEMIOLOGY AND OUTCOMES OF ELECTRIC BURN INJURY AT TERTIARY CARE CENTER IN JODHPUR, RAJASTHAN

2019 ◽  
Vol 3 (6) ◽  
Author(s):  
Bharti Saraswat ◽  
Ashok Yadav ◽  
Krishna Kumar Maheshwari
Keyword(s):  
Burn Injury ◽  
Low Voltage ◽  
Care Center ◽  
Tertiary Care ◽  
The Body ◽  
Electrical Injury ◽  
Age Group ◽  
Electric Circuits ◽  
Medical College ◽  
Social Burden

Background- Electric burns and injuries are the result of electric current passing through the body. Temporary or permanent damage can occur to the skin, tissues, and major organs. Methods- This prospective study was carried out on patients admitted in burn unit of department of surgery M.G. Hospital associated with Dr. S.N. Medical College Jodhpur. Records of the patients admitted from January 2018 to December 2018 were studied. Bed head tickets of the patients evaluated in detail. Results- In our study out of 113 patients maximum no. of patients were in age group of 21-30 years 44 (38.94%) followed by age group <11 years in 21 (18.58%) patients and age group of > 60 years in only 3 (2.65%).39 (34.51%) patients were farmer and 15 (13.27%) were electrician in out of 113 total patients, while 37 (32.74%) were without any occupation. 65 (57.52%) cases of high voltage (HV) electrical injury and 48 (42.48%) cases were of low voltage (LV) electrical injury. Conclusion- Morbidity leading to permanent disabilities make the person physically dependent on others. It can be prevented by educating the people about the proper handling to electric circuits & devices. Proper communication among the electricians may help in lowering such accidents. Proper rehabilitation of the handicapped person & employment to the member of the affected family may reduce the social burden caused by such electricity concerned accidents.

scholarly journals Human Machine and Thermoelectric Energy Scavenging for Wearable Devices

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Vladimir Leonov
Keyword(s):  
Thermal Properties ◽  
Heat Flow ◽  
Thermal Resistance ◽  
Wearable Devices ◽  
The Body ◽  
Energy Scavenging ◽  
Wearable Electronics ◽  
Ambient Temperatures ◽  
Thermoelectric Energy ◽  
Temperature Heat

Thermal properties of humans were studied in the case where a small-size energy scavenger is placed on the body. In such a case, the human being serves as a heat source for the thermopile of the scavenger, but the latter serves as a thermally insulating object. As a result, the body properties, namely, the skin temperature, heat flow, and thermal resistance locally change. This is the result of redirection of heat flow inside the body to colder zones because of thermal insulation provided by the scavenger. Increased thermal resistance of human body, in turn, affects the design of the scavenger. The analysis of such scavenger performed for ambient temperatures of 0°C to 25°C shows that it could reach competitive performance characteristics and replace batteries in low-power wearable electronics. A simulated power of up to 60 μW/cm2 at 0°C has been validated by using wearable thermoelectric modules.

Force and power of flapping plates in a fluid

2012 ◽  
Vol 712 ◽  
pp. 598-613 ◽  
Author(s):  
Gao-Jin Li ◽  
Xi-Yun Lu
Keyword(s):  
Dynamic Analysis ◽  
Numerical Solutions ◽  
Vortical Structure ◽  
Three Dimensional ◽  
The Body ◽  
Vortical Structures ◽  
Ring Model ◽  
Essential Properties ◽  
Physical Insight ◽  
Insight Into

AbstractThe force and power of flapping plates are studied by vortex dynamic analysis. Based on the dynamic analysis of the numerical results of viscous flow past three-dimensional flapping plates, it is found that the force and power are strongly dominated by the vortical structures close to the body. Further, the dynamics of the flapping plate is investigated in terms of viscous vortex-ring model. It is revealed that the model can reasonably reflect the essential properties of the ring-like vortical structure in the wake, and the energy of the plate transferred to the flow for the formation of each vortical structure possesses a certain relation. Moreover, simplified formulae for the thrust and efficiency are proposed and verified to be reliable by the numerical solutions and experimental measurements of animal locomotion. The results obtained in this study provide physical insight into the understanding of the dynamic mechanisms relevant to flapping locomotion.

scholarly journals Sperm Transfer Through the Vector Tissue in Piscicola Respirans (Clitellata, Hirudinea, Piscicolidae)

2009 ◽  
Vol 54-55 (1-4) ◽  
pp. 5-12 ◽  
Author(s):  
Piotr ŚwiĄtek ◽  
Anna Świder ◽  
Aleksander Bielecki
Keyword(s):  
High Pressure ◽  
Connective Tissue ◽  
Body Wall ◽  
The Body ◽  
Sperm Transfer ◽  
Ultrastructural Observation ◽  
Granular Cells ◽  
Main Mass ◽  
Tissue Cells ◽  
Cytoplasmic Processes

Sperm Transfer Through the Vector Tissue in Piscicola Respirans (Clitellata, Hirudinea, Piscicolidae) In fish leeches (Piscicolidae) indirect (hypodermic) insemination has evolved, thus the spermatophores are released in the specialised region of the body wall known as a copulatory area or a copulatory region. The way in which the spermatozoa reach the ovaries is not fully understood. In piscicolids beneath the copulatory area there is a specialized connective tissue (vector tissue), which is thought to guide the spermatozoa toward the ovaries. To date the structure of the vector tissue has not been observed in copulating specimens, which have spermatophores implanted in their coplulatory area. Here we present the first ultrastructural observation of massive sperm transfer from the spermatophore throughout the vector tissue to the ovaries. Our results show that the sperm transfer is both massive and rapid. The migrating spermatozoa form huge aggregations which push aside the vector tissue cells, in such a way that between these cells voluminous gaps are formed. Unexpectedly to our previous suggestions, the ultrastructural pictures show that the long cytoplasmic processes of granular cells, which constitute the main mass of the vector tissue, are not engaged in sperm transport. We suggest that the sperm is pumped with a high pressure from the spermatophore into the vector tissue, and as a result the vector tissue cells are pushed aside and spermatozoa can freely pass between them.

Simulation Analysis for Supercavitation Projectiles Penetrating into Metal Targets

2012 ◽  
Vol 217-219 ◽  
pp. 1449-1454
Author(s):  
Wei Cao ◽  
Tie Zhi Sun ◽  
Cong Wang ◽  
Xin Hua Zhao
Keyword(s):  
Dynamic Analysis ◽  
Penetration Depth ◽  
Simulation Analysis ◽  
The Body ◽  
Analysis Software ◽  
Target Plate ◽  
Two Peaks

The process of the supercavitation projectile penetrating into metal targets was simulated by using the dynamic analysis software ANSYS/LS-DYNA, and the deformation、breakage and forces on the body in different initial velocities and the penetration depth were discussed. Analysis results show that there are two peaks of resistance and the velocities is variety almost in linear attenuation when the cone part of the projectile is moving through contacted with the target plate, which provides references for the structure and parameters design of the supercavitation projectile.

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