Cantilever Research Papers - Academia.edu (original) (raw)

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Recent papers in Cantilever

Microelectromechanical systems (MEMS) are micrometre-size systems that are capable of transforming electrical signals to mechanical signals. In this paper, the use of MEMS devices as a method for harvesting waste heat is explored. A... more

Microelectromechanical systems (MEMS) are micrometre-size systems that are capable of transforming electrical signals to mechanical signals. In this paper, the use of MEMS devices as a method for harvesting waste heat is explored. A background for the technology and methods is discussed and a method proposed for a working device based upon a thermally heated bimorph actu-ated by waste radiation alone is investigated. A chopper interrupts the radiant energy inducing an oscillation in the bimorph temperature and thus creates a mechanical motion which can be taken advantage of using piezo-electric materials. Difficulties in harvesting radiant energy with this method are highlighted and suggestions for non-passive energy generation are made based on the outlined principles.

This work experimentally and numerically studies large deflection of slender cantilever beam of linear elastic material, subjected to a combined loading which consists of internal vertical uniformly distributed continuous load and... more

This work experimentally and numerically studies large deflection of slender cantilever beam of linear elastic material, subjected to a combined loading which consists of internal vertical uniformly distributed continuous load and external vertical concentrated load and a horizontal concentrated load at the free end of the beam. We got equations with the help of large deflection theory, and present the differential equation governing the behaviour of this system and show that that this equation, although straightforward in appearance, is in fact rather difficult to solve due to the presence of a non-linear term. A numerical evaluation is used to evaluate the system and calculate Young`s modulus of the beam material. With simple experiment we show, how a Young`s modulus can be obtained and then the phenomenon of the large elastic sideways deflection of a column under compressive loading is investigated and elastica of buckled column is calculated.

The design and materials of a prosthesis affect the loading of dental implants and deformation of the bone. The aim of the study was to evaluate the effects of prosthesis design and materials on the stress distribution of... more

The design and materials of a prosthesis affect the loading of dental implants and deformation of the bone. The aim of the study was to evaluate the effects of prosthesis design and materials on the stress distribution of implant-supported prostheses.A 3-dimensional finite element analysis method was selected to evaluate the stress distribution in the bone. Three different models were designed as follows: a 3-unit implant-supported fixed partial denture (FPD) composed of a metal framework and porcelain veneer with (M2) or without a cantilevered extension (M1) and an FPD composed of a fiber-reinforced composite (FRC) framework and a particulate composite veneer without a cantilevered extension (M3). In separate load cases, 300-N vertical, 150-N oblique, and 60-N horizontal forces were applied to the prostheses in the models. von Mises stress values in the cortical and cancellous bone were calculated.In cortical bone, the highest von Mises stresses were noted in the M2 Model with a vertical load; whereas, higher stresses were observed in the M1 Model with horizontal and oblique loads. The lowest stress values were determined in the M3 Model for all loading conditions. In cancellous bone, decreased stress values were found with all 3 models under the applied loads.Prosthesis design and materials affect the load-transmission mechanism. Although additional experimental and clinical studies are needed, FRC FPDs can be considered a suitable alternative treatment choice for implant-supported prostheses. Within the limitations of the study, the 3-unit FPD supported by 2 implants with a cantilevered extension revealed acceptable stress distributions.

The authors report the nanomachining of sub-20-nm wide doubly clamped silicon carbon nitride resonators using low keV electron beam lithography with polymethyl methacrylate resist and cold development. Methodologies are developed for... more

The authors report the nanomachining of sub-20-nm wide doubly clamped silicon carbon nitride resonators using low keV electron beam lithography with polymethyl methacrylate resist and cold development. Methodologies are developed for precisely controlling the resonator widths in the ultranarrow regime of 11–20 nm. Resonators with lengths of 1–20 μm and widths of 16–280 nm are characterized at room temperature in vacuum using piezoelectric actuation and optical interferometry. Clamping and surface losses are identified as the dominant energy loss mechanisms for a range of resonator widths. The resonator clamping points are optimized using an original electron beam lithography simulator. Various alternative clamping point designs are also modeled and fabricated in order to reduce the clamping losses.

The effect of temperature on structural response is a concern in engineering applications. The literature has highlighted that applied temperature loads change the system vibration behaviour. However, there is limited information... more

The effect of temperature on structural response is a concern in engineering applications. The literature has highlighted that applied temperature loads change the system vibration behaviour. However, there is limited information available about temperature impacting the dynamic response. This paper investigated the heating rates effects on modal parameters for both with crack and without crack conditions in a cantilever beam. A beam subjected to three heating rates was considered: 2, 5, and 8 °C/min. The first one was assumed as a slow heating rate while the others were assumed as moderate and high, respectively. This controlled rate of heating was achieved by using a proportional-integral-derivative (PID) temperature controller. The results showed that heating at different rates has little impact on modal parameters. While this effect is minimal at lower temperatures and more evident at higher temperatures. The results of temperature ramped at 2, 5, and 8 °C/min were compared with...

This Master Thesis in Technical Mathematics at LTH, directed towards simulation and computation, has treated the subject of fluid-structure interaction (FSI) for incompressible flow with small vibrations. The open source packages DEAL.II... more

This Master Thesis in Technical Mathematics at LTH, directed towards simulation and computation, has treated the subject of fluid-structure interaction (FSI) for incompressible flow with small vibrations. The open source packages DEAL.II and OpenFOAM have been used to create a coupling between a finite element formulation for structure and a finite volume formulation for fluid ( gas or liquid ). A staggered solution algorithm for FSI has been implemented in C++ using Aitkens relaxation method together with a Reduced-Order-Model (ROM). The solution algorithm has been validated by using an application consisting of a cantilever immersed in a steady flow transversal to its axial direction. Also, vortex-induced vibrations (VIV) were calculated as a function of the flow velocity and successfully compared to empirical data. The study has demonstrated the usefulness of artifical damping to solve boundary condition problems in incompressible flow. The method presented is general and has a s...

Instrumentation and techniques are described to image small objects, such as but not limited to individual human chromosomes, with nanometer resolution. This instrument and method are also used to cut-off identified parts of objects, to... more

Instrumentation and techniques are described to image small objects, such as but not limited to individual human chromosomes, with nanometer resolution. This instrument and method are also used to cut-off identified parts of objects, to move around and manipulate the cut-off parts on the substrate on which they are being imaged to predetermined locations on the substrate, and to remove the cut-off parts from the substrate. This is accomplished using an atomic force microscope (AFM) and by modification of the conventional cantilever stylus assembly of an AFM. The plural cantilevers are used with either sharp-tips or knife-edges. In addition, the invention can be utilized for measuring the hardness of materials. 10 figs.

Large flexible structures and aerospace structures can be studied by building a model flexible beam with an appendage. The appendage can be used as a passive or an active vibration absorber for a structure under sinusoidal and random... more

Large flexible structures and aerospace structures can be studied by building a model flexible beam with an appendage. The appendage can be used as a passive or an active vibration absorber for a structure under sinusoidal and random excitation. In this study, a cantilever beam-tip mass-pendulum system is investigated by using Finite Element method (FEM). Dynamical behaviour of the model

Multifunctional structures are pointed out as an important technology for the design of aircraft with volume, mass, and energy source limitations such as unmanned air vehicles (UAVs) and micro air vehicles (MAVs). In addition to its... more

Multifunctional structures are pointed out as an important technology for the design of aircraft with volume, mass, and energy source limitations such as unmanned air vehicles (UAVs) and micro air vehicles (MAVs). In addition to its primary function of bearing aerodynamic loads, the wing/spar structure of an UAV or a MAV with embedded piezoceramics can provide an extra electrical energy source based on the concept of vibration energy harvesting to power small and wireless electronic components. Aeroelastic vibrations of a lifting surface can be converted into electricity using piezoelectric transduction. In this paper, frequency-domain piezoaeroelastic modeling and analysis of a cantilevered platelike wing with embedded piezoceramics is presented for energy harvesting. The electromechanical finite-element plate model is based on the thin-plate (Kirchhoff) assumptions while the unsteady aerodynamic model uses the doublet-lattice method. The electromechanical and aerodynamic models ar...

The structure of a simple rental apartment building of the Sumatran Technology Institute had been modeled using the Performance Based Design method. The aim of this study was to obtain the base shear and maximum displacement as well as... more

The structure of a simple rental apartment building of the Sumatran Technology Institute had been modeled using the Performance Based Design method. The aim of this study was to obtain the base shear and maximum displacement as well as the performance level of the building structure models in resisting the combination of gravitation and lateral earthquake loads. The loads were based on the function and location of the building. The building structures had been designed as a double system, namely the beam-column frames and shear walls in the direction of the XZ and YZ axis. There were four models: the models with a double system according to the original design, the beam-column frames without XZ shear walls, the beam-column frames without YZ shear walls, and the beam-column frames without shear walls. The results of the analysis at the performance level showed that the model with a double system was able to resist the highest base shear while the frames system without shear walls was...

The biodegradable polymer poly(l-lactide) (PLLA) was introduced for the fabrication of micromechanical devices. For this purpose, thin biopolymer films with thickness around 10μm were spin-coated on silicon substrates. Patterning of... more

The biodegradable polymer poly(l-lactide) (PLLA) was introduced for the fabrication of micromechanical devices. For this purpose, thin biopolymer films with thickness around 10μm were spin-coated on silicon substrates. Patterning of microcantilevers is achieved by nanoimprint lithography. A major challenge was the high adhesion between PLLA and silicon stamp. Optimized stamp fabrication and the deposition of a 125nm thick fluorocarbon anti-stiction

We present a cantilever based Micro-electromechanical System (MEMS) humidity sensor for applications of environmental monitoring. The main aim of this paper is to design, simulate and analyze the micro cantilever based MEMS sensor such as... more

We present a cantilever based Micro-electromechanical System (MEMS) humidity sensor for applications of environmental monitoring. The main aim of this paper is to design, simulate and analyze the micro cantilever based MEMS sensor such as V, U and W shaped cantilever using Polyimide sensing material. The performance of metrics such as the maximum induced stress, deflection and sensitivity obtained through the finite element tool have been analyzed using the simulation software INTELLISUITE v8.7. A designed Si cantilever humidity sensor based on mechanical principles of displacement analysis is being performed on the sensor. The sensing material as Polyimide is coated over the beam to sense the humidity. When the humidity absorbed by the Polyimide material, the mass of the beam is also increased. The change in humidity element is bending of the micro cantilever that modifies the measured displacement between the substrate and the micro cantilever. With this change in displacement gives the measure of the amount of water vapor present in that environment. Therefore the result of these device studies can be used to enhance the sensitivity and stress. Finally, we observed that the best output displacement, Mises stress and sensitivity responses are obtained from W shaped cantilever in the range of 10%RH to 100% RH.

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