Papers by Keyword: Cantilever Beam

Abstract: Measurement of strain and stress plays a crucial role in advancing research in mechanical engineering. In this paper, the bending strain and stress of the steel cantilever beam subjected to concentrated loads at the free end are investigated using analytical, experimental, and numerical approaches. The experimental investigation was carried out through the use of a strain gauge sensor connected with a Wheatstone quarter-bridge configuration. The strain gauge used in this experiment is interfaced with the NI SignalExpress software in conjunction with the NI modules to ensure accurate data acquisition. The experimental measurements provide essential benchmark values for comparison with the numerical results. The numerical simulation is developed using ANSYS Workbench. The comparison results show that the experimental values have good agreement with the simulated FEM and analytical values. The findings of this study provide valuable insights into the bending strain characteristics of steel cantilever beams and contribute to the advancement of mechanical engineering research.

Abstract: The paper discusses the effect of functional grading on the position of neutral axis of a cantilever beam. The principle of virtual work is used to derive the governing equations and B-spline collocation method is used to solve the governing equations. The material distribution is done using power law function. The position of neutral axis plays an important role in designing a composite beam. The present analysis gives a brief insight into the effect of power index on the depth of neutral axis measured from the centroidal axis. The results show the influence of modulus ratio on the position of neutral axis. Effect of shift in neutral axis further influence the stress values and deflection.

Abstract: The main purpose of this study is a numerical assessment of the consequences of an explosion of a hydrogen-air cloud on the personnel of a hydrogen fueling station and the strength of a protective solid wall of certain dimensions. An explosive gas mixture is formed as a result of the destruction of high-pressure cylinders, the number of which determines the size of the cloud, the power of the explosion, and the scale of the consequences of environmental impact. To obtain the spatio-temporal distribution of the maximum overpressure and the impulse of the shock wave compression phase, a mathematical model of the dispersion of an active gaseous admixture is used, taking into account the chemical interaction with air oxygen. The probable consequences of the shock-impulse impact on the personnel at the control point are carried out using probit analysis. The values of the maximum bending moment and stress at the base of the protective wall, which result from the impact of the blast wave, are used to deterministically estimate the minimum wall thickness necessary for the safe operation of the protective device. The mathematical model takes into account the complex terrain and the three-dimensional non-stationary nature of the shock wave propagation process, and it is a source of data necessary to solve the problem of the strength of solid objects located in the area of baric perturbation of the gaseous medium. The developed methodology makes it possible to carry out a comparative analysis of the effectiveness of protective structures in relation to the power of the explosion.

Abstract: The work is focussed on measuring model parameters of a piezoelectric bending energy harvester cantilever beam with sputter coated technique using finite element analysis. The beam was studied for a wide range of frequencies of about 100-1200Hz. The finite element simulation results confirm that the vibrations in the above mentioned frequency range can be effectively utilised to generate energy. Design of electrometrical vibration energy harvester was carried out with literature survey and the effect was analysed for the given length of beam to the voltage produced by the harvester. The Electromagnetic analysis induced voltage is validated with the help of commercial finite element software ANSYS. The simulation results revealed that the effect of sputter coating on the beam will increase the power generation.

Abstract: In order to overcome the limitations of common methods for measuring elastic modulus of the ultra-thin glass，a novel method is proposed for measuring the elastic modulus of the ultra-thin glass by cantilever beam vibration method．The measurement principle，apparatus，and manipulation were introduced. In this method, the measured ultra-thin glass is generated in the form of a cantilever beam, and the cantilever beam can be vibrated for a short time when transient excitation is applied. The natural frequency of the cantilever beam can be used to calculate the elastic modulus of the ultra-thin glass material. A series of ultra-thin glass samples with different thickness were tested in this work, the measured values are consistent with that given . The effect of beam length/thickness ratio on determination of elastic modulus of materials by means of cantilever method was analyzed, the result shows that the influence of the ratio can be neglected if the beam length is equal to or more than 10 times of the beam thickness.

Abstract: Machines, cars suspensions, buildings steel constructions etc. usually generate vibrations, which can be the excitement signal for piezoelectric energy harvesters. The piezoelectric patches attached to the vibrating construction have ability to convert mechanical energy of harmful vibrations into electrical energy.The goal of the study was to verify a finite element model of the piezoelectric beam energy harvester by comparing results of numerical simulations with those obtained experimentally. The stand used in the experiment consists of the cantilever beam with piezoelectric elements attached, which is excited by the base harmonic movement. The transverse displacements of the selected beam’s point and the base, and also the frequency of vibrations were observed and measured using an accelerometer and a B&K Pulse platform. A portable data acquisition module was used to quantify the voltage generated by the piezoelectric layers.The finite element model was built in ANSYS software. The beam and piezoelectric layers were modeled by twenty node elements with an additional electric degree of freedom for piezoelectric elements. A full piezoelectric matrix was used in the finite element analysis instead of a one-dimensional piezoelectric effect, which dominates in many analytical approaches. It allowed building a more accurate model of the system. The experimental tests and finite element method simulations were performed and acquired results were compared. The characteristics of voltage amplitude in the time and frequency domain were shown and discussed.

Abstract: Harvesting ambient vibration energy through piezoelectric (PE) means is a popular energy harvesting technique. The merit of applying PE means to supply energy for microelectronic devices is that they can reduce the battery weight and possibly make the device self-powered by harvesting mechanical energy. This investigation will examine the energy generating performance of miniature PE cantilever beam through theoretical modeling, simulation and experiment testing. Through the theoretical analysis of the piezoelectric energy harvesting structure, the expression of open circuit voltage output is obtained. Using ANSYS software, the working performance of piezoelectric cantilever beam is analyzed. On the basis of theoretical analysis and simulation optimization, a set of experimental system is established to test the energy harvesting performance of the piezoelectric cantilever beam. The testing result shows that the harvested energy by the piezoelectric cantilever beam could supply electrical power to some micro electrical devices.

Abstract: This research proposes an improved tunable piezoelectric harvester structure which is constructed by a cantilever base beam and piezoelectric elements working in d33 mode. Our previous work on tunable piezoelectric harvester structure showed a frequency variation ratio of 3.17% with piezoelectric elements working in d31mode coupling. In this work, by changing the working mode of the piezoelectric elements from d31 to d33 mode, the frequency variation ratio was shown to be much higher. Theoretical analysis of the improved structure was investigated and verified with simulations. The results showed that the d33 mode coupling surpasses the d31 mode coupling with a frequency variation ratio of 29.74%.

Abstract: It has been well known that bone has piezoelectric properties and these properties have been considered to be caused by the shift of the center of symmetry of the positive and negative electrical charge due to the strain of the collagen fibers included in the bone. Thus, it has long been considered that there were no piezoelectric effects in the hexagonal hydroxyapatite (HAp) which has center of symmetry of crystal. However, in recent years, the piezoelectric property of artificially synthesized HAp was reported. In the authors’ previous report, a new result which showed the piezoelectricity of the hydroxyapatite (HAp) films fabricated by the pulsed laser deposition (PLD) method was reported. In this study, the effect of poling treatment on piezoelectric constant of pulsed laser deposited HAp films was investigated.

Abstract: Dielectric elastomer sensors are a new kind of capacitive sensors. They can be used to measure forces, pressures and deformations. The sensors have several advantages such as high elasticity and inexpensive fabrication compared with traditional sensors. In this paper, a new sensing device for measuring small concentrated force is proposed. The structure of the device is a cantilever beam with constant strength on which is fixed the dielectric membrane. The dielectric membrane is a capacitance sensor built with dielectric polymer coated with soft electrodes. When the cantilever beam is subjected to a concentrated force at its free end, the strain changed in the cantilever beam will induce the change in the capacitance of the membrane. According to the relation, the unknown concentrated force can be monitored by measuring the change in the capacitance. The testing results on the device show that the concentrated force at the free end of the cantilever beam is approximately proportional to the change in the capacitance. The prototype demonstrated the new device is capable of monitoring small concentrated force with prominent sensitivity.