• 한국기계가공학회지
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• 제6권2호
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• pp.22-27
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• 2007

In this study, the two methods of stiffness measurement(Spring constant) of cantilever were proposed for quantitative measurement in Atomic Force Microscopy(AFM). As the 1st method for the measurement of stiffness, the probe method, which is used in the measurement of the semiconductor mechanical and electrical properties, was applied to the measurement of the cantilever. Experiments by the probe method were performed finding the resistance value of cantilever. As the results, the resistance was measured differently along with the dimension and the thickness of cantilever that determined the stiffness(spring constant) of the lever. As the 2nd method, the vibration characteristics(Dunkerley expression) is used to obtain the stiffness of the complex structure which is combined by AFM cantilever and the standard cantilever. We measured the resonant frequency from the complex structure using the micro stages and stereo microscope. As the results, we confirmed that the vibration characteristics(Dunkerley expression) is effected the micro complex structure of AFM cantilever.

• Interaction and multiscale mechanics
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• 제1권4호
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• pp.449-465
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• 2008

In this paper a general approach for studying the motion of a cantilever beam interacting with a 2D fluid flow is presented. The fluid is solved by a general purpose commercial computational fluid dynamics (CFD) package (FLUENT 6.2), while the structure is managed by means of a dedicated finite element method solver, coded in FLUENT as a user-defined function (UDF). A weak fluid structure interaction coupling scheme is adopted exchanging information at the end of each time step. An arbitrary cantilever beam can be introduced in the CFD mesh with its wetted boundaries specified; the cantilever can also interact with specified rigid and flexible walls through use of a non-linear contact algorithm. After a brief review of relevant scientific contributions, some test cases and application examples are presented.

• 한국세라믹학회지
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• 제51권5호
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• pp.516-521
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• 2014

This paper describes the development of a new piezoelectric unimorph cantilever structure intended to improve electrical output power, compared to a conventional cantilever. The proposed structure employs a cylindrical bar attached to one side of a steel plate, which is a significant factor in forced vibration mode. The feasibility of the proposed methodology was assessed experimentally and theoretically. The influence of three different types of bar material (i.e., stainless steel, silicon rubber, and urethane), and bar position, on the output voltage were examined and compared with those without the bar. The optimal position and material for the bar were identified through experimental and theoretical analyses. It appears that the electrical output power of the proposed cantilever is about 40% higher than that of a conventional unimorph cantilever.

• 한국재료학회지
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• 제17권2호
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• pp.121-123
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• 2007

Energy harvesting from the vibration through the piezoelectric effect has been studied for powering the wireless sensor node. As piezoelectric unimorph cantilever structure can transfer low vibration to large displacement, this structure was commonly deployed to harvest electric energy from vibrations. Piezoelectric unimorph structure was composed of small stiff piezoelectric ceramic on the large flexible substrate. As there is the large Young's modulus difference between the flexible substrate and stiff piezoelectric ceramic, flexible substrate could not homogeneously transfer the vibration to stiff piezoelectric ceramic. As a result, most piezoelectric ceramics had been broken at the certain point. We measured and analyzed the stress distribution on the piezoelectric ceramic on the cantilever.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1609-1613
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• 2003

This research focused on the development of automatically exclusive production equipment of corrupad as changing manual system into automatic system to increase the output. Therefore the minimization of the problem of the rewinding mechanism with eccentric cantilever structure is key to the achievement of the high performance for automation production. Proto-type corrupad rewinding machine is manufactured after considering the effect of the rotational vibration and natural frequency of the structure of machine by using 3D design packages such as ADAMS and I-deas. For evaluating the performance of the proto-type machine, simulations of dynamic and static characteristics using 3D design packages, a series of modal tests by accelerometer and measurements of dynamic behavior by high-speed camera for rewinding part, were carried out. As a result, the proto-type machine was not affected with the rotational vibration. Whirling error of eccentric cantilever structure in driving is small. Therefore the machine developed is most suitable to produce corrupad automatically. However reinforcement of the structure in axial direction is required due to so vibration in that direction.

• 한국공작기계학회논문집
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• 제12권2호
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• pp.9-16
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• 2003

A strategy of the optimal shape design with FEA(Finite Element Analysis) for 2-D structure is proposed by comparing subproblem approximation method with first order approximation method. A cantilever beam with two different loading conditions, a concentrated load and an evenly distribute load, and truss structure with a concentrated loading condition are implemented to optimize the shape. It gives a good design strategy on the optimal truss structure as well as the optimal cantilever beam shape. It is found that the convergence is quickly finished with the iteration number below ten. Optimized shapes of cantilever beam and truss structure are shown with stress contour plot by the results of the subproblem approximation method and the first order approximation methd.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.48.1-48.1
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• 2005

• 대한기계학회논문집B
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• 제27권2호
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• pp.236-242
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• 2003

Thermal bubbles find their diverse application areas in the MEMS (MicroElectroMechanial Systems) technology, including bubble jet printers, microactuators, micropumps, etc.. Especially, microactuators and micropumps, which use a microbubble growing by a controlled heat input, frequently involve mechanical and thermal interaction of the bubble with a solid structure, such as a cantilever beam and a membrane. Although the concept is experimentally verified that an internal pressure of the bubble can build up high enough to deflect a thin solid plate or a beam, the physics of the entire process have not yet been thoroughly explored. This work reports the experimental study of the growth of a thermal bubble while deflecting a thin cantilever beam. A physical model is presented to predict the elastic response of the cantilever beam based on the experimental measurements. The scaling law constructed through this work can provide a design guide for micro- and nano-systems that employ a thermal bubble for their actuation/pumping mechanism.

• Tribology and Lubricants
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• 제34권4호
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• pp.125-131
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• 2018

A precision tribometer consisting of a cantilever was designed to measure frictional forces in the micro-Newton range. As frictional forces are measured based on the bending of the cantilever, vibration of the cantilever is the most significant factor affecting the quality of the friction measurement. Therefore, improved design of the tribometer with double cantilevers and a connecting plate that united the two cantilevers mechanically was suggested. For the verification of the modified design of the tribometer, numerical analysis and experiments were conducted. Examination using the finite element method revealed that the tribometer with a double cantilever and a connecting plate exhibited faster damping characteristics than the tribometer with a single cantilever. In the experiment, effectiveness of the double cantilever and connecting plate for vibration reduction was also confirmed. Vibration of the tribometer with double cantilever decreased eight times faster than that of the tribometer with a single cantilever. The faster damping of the double cantilever design is attributed to the mechanical interaction at the contacting surfaces between the cantilever and the connecting plate. Tribotesting using the tribometer with a single cantilever resulted in random fluctuation of frictional forces due to the stick-slip behavior. However, using the tribometer with a double cantilever and connecting plate for the tribotest gave relatively uniform and steady measurement of frictional forces. Increased stiffness owing to using a double cantilever and mechanical damping of the connecting plate were responsible for the stable friction signal.

• JSTS:Journal of Semiconductor Technology and Science
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• 제2권4호
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• pp.246-252
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• 2002

Two kinds of PZT cantilevers integrated with a piezoresistor have been newly designed, fabricated, and characterized for high speed AFM. In first cantilever, a piezoresistor is used to sense atomic force acting on tip, while in second cantilever, a piezoresistor is integrated to calibrate hysteresis and creep phenomena of the PZT cantilever. The fabricated PZT cantilevers provide high tip displacement of $0.55\mu\textrm{m}/V$ and high resonant frequency of 73 KHz. A new cantilever structure has been designed to prevent electrical coupling between sensor and PZT actuator and the proposed cantilever shows 5 times lower coupling voltage than that of the previous cantilever. The fabricated PZT cantilever shows a crisp scanned image at 1mm/sec, while the conventional piezo-tube scanner shows blurred image even at $180\mu\textrm{m}/sec$. The non-linear properties of the PZT actuator are also well calibrated using the piezoresistive sensor for calibration.