• Journal of Drive and Control
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• v.17 no.4
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• pp.97-102
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• 2020

This paper presents the basic research for the design and fabrication of a 3D-printed load cell made of NCPC (nano-carbon piezo-resistive composite). We designed a structure that can resonate at a low frequency range of about 5-6 Hz with ANSYS using sensitivity analysis and a response surface method. The design was verified by fabricating the device with a low-quality commercial 3D printer and ABS filament. We conducted a feasibility test for a commercial sensor using 1000 cyclic load tests at 0.3 Hz in a material testing system. A manufacturing process for the 3D printer filament based on the NCPC was also developed using the nano-composite process.

• Steel and Composite Structures
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• v.35 no.4
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• pp.545-554
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• 2020

The present paper explores nonlinear dynamical properties of piezo-magnetic beams based on a nonlocal refined higher-order beam formulation and piezoelectric phase effect. The piezoelectric phase increment may lead to improved vibrational behaviors for the smart beams subjected to magnetic fields and external harmonic excitation. Nonlinear governing equations of a nonlocal intelligent beam have been achieved based upon the refined beam model and a numerical provided has been introduced to calculate nonlinear vibrational curves. The present study indicates that variation in the volume fraction of piezoelectric ingredient has a substantial impact on vibrational behaviors of intelligent nanobeam under electrical and magnetic fields. Also, it can be seen that nonlinear free/forced vibrational behaviors of intelligent nanobeam have dependency on the magnitudes of induced electrical voltages, magnetic potential, stiffening elastic substrate and shear deformation.

• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.184.1-184
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• 2003

• Composites Research
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• v.16 no.2
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• pp.41-47
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• 2003

This paper is concerned with the performance evaluation and comparison analysis fur several kinds of LIPCA (Lightweight Piezo-Composite Actuator) device system. LIPCA device system is composed of a piezoelectric ceramic layer and fiber reinforced light composite layers, typically a PZT ceramic layer was sandwiched by a top fiber layer with low CTE (coefficient of thermal expansion) and base layers with high CTE. To investigate the effect of lay-up structure of the LIPCA on the actuating performance, four kinds of actuator with different lay-up stacking sequence were designed, manufactured, and tested. The performance of each actuator was evaluated using an actuator test system consisted of an actuator supporting jig, a high voltage actuating power supplier, and a non-contact laser measuring system. From the comparison of the performance of the LIPCA prototypes, it was found that the actuator with higher coefficient of unimorph actuator can generate larger actuating displacement.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.3
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• pp.37-44
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• 2004

This paper deals with the performance analysis of LIPCA(Light-weight Piezo-Composite actuator) including the material nun-linearity of the embedded 3203HD PZT wafer. For this analysis, we used a piezo-shell element code based on a nine-node assumed strain shell element formulation. The material non-linearity was implemented in the formulation due to a large observed discrepancy between the measured displacement and the computed actuation displacement based on the linear analysis. An experimentally extracted piezo-strain function of the PZT wafer and incremental formulation were incorporated into the linear finite element code to improve the accuracy of the estimated actuation displacement of the LIPCA. The non-linear piezo-shell program was used to predict the non-linear performance of the LIPCA. The simulated actuation displacement from the non-linear code showed much better agreement with the measured data.

• Journal of Mechanical Science and Technology
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• v.16 no.5
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• pp.666-675
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• 2002

Piezoelectric Fiber Composites with Interdigitated Electrodes (PFCIDE) were previously introduced as an alternative to monolithic wafers with conventional electrodes for applications of structural actuation. This paper is an investigation into the performance improvement of piezoelectric fiber composite actuators by changing the matrix material. This paper presents a modified micro-electromechanical model and numerical analyses of piezoelectric fiber/piezopolymer matrix composite actuator with interdigitated electrodes (PFPMIDE). Various concepts from different backgrounds including three-dimensional linear elastic and dielectric theories have been incorporated into the present linear piezoelectric model. The rule of mixture and the modified method to calculate effective properties of fiber composites were extended to apply to the PFPMIDE model. The new model was validated when compared with available experimental data and other analytical results. To see the structural responses of a composite plate integrated with the PFPMIDE, three-dimensional finite element formulations were derived. Numerical analyses show that the shape of the graphite/epoxy composite plate with the PFPMIDE may be controlled by judicious choice of voltages, piezoelectric fiber angles, and elastic tailoring of the composite plate.

• Journal of the Korean Geotechnical Society
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• v.21 no.5
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• pp.215-223
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• 2005

Piezo-ceramics are special materials which transform energy from mechanical to electrical forms and vice versa. Bender elements are composite materials consisting of thin piezo-ceramics and elastic shims, and are widely used as actuators and transducers in the field of electronics, robotics, autos and mechatronics utilizing the effectiveness of energy transformation capability. In geotechnical engineering, commercial bender elements are used in laboratory as source and receiver in the measurements of soil stiffness. The elements were built by using various metal shims sandwiched between piezo-ceramics and coating over the composite in the research. A pair of elements were buried in a concrete block and used as source and receiver to measure the stiffness of the concrete. The test results were verified by comparing with the resonant column testing results. In a preliminary stage of the development of an in-situ seismic testing equipment using bender elements for soft clay materials, shear waves were generated and measured by burying the elements in the barrel of kaolinite and water mixture. The measured shear wave signals were so distinct for the first-arrival pick that applicability of the elements in the field measurements could be very promising.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.1
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• pp.7-13
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• 2008

In this paper, the pumping performance of a piezoelectric valveless micropump is simulated with a commercial finite element analysis software, COMSOL Multiphysics. The micropump developed in the previous work is composed of a 4-layer lightweight piezo-composite actuator (LIPCA), a polydimethylsiloxane (PDMS) pump chamber, and two diffusers. The piezoelectric domain, structural domain and fluid domain are coupled in the simulation. Water flow rates are numerically predicted for geometric parameters of the micropump. Based on this study, the micropump is optimally designed to obtain its highest pumping performance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.11-14
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• 2000

This paper presents the vibration control of a glass-fiber reinforced thermoplastic composite beam with a distributed PVDF sensor and piezo-ceramic achlator. The three types of different controllen which are PID, H$\infty$ , and p-synthesis ontrollcr are employed to achieve vibration suppression in the transient vibration of composite beam. In the H$\infty$ , controller design, 1st and 2nd natural frequencies are considered in the modeling, because robust control theory which has robustness to struchred uncertainty is adopled Lo suppress the vibration. If the controller designed by H$\infty$ , theory does not satisfy control performance, it is improved by $\mu$ -synthesis method with D-K iteration so that the$\mu$-contoller based on the structured singular value satisfies the nominal performance and robust performance Simulations and experiments were carried out with the designed controllers m order to demonstrate the suppression efficiency of each controller.

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.11a
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• pp.15-21
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• 1999

This study investigates the free and forced vibration characteristics of an annular piezoelectric motor stator constructed of two piezoelectric material layers and one stainless steel layer. The annular piezoelectric motor stator is subjected to a travelling load produced by piezo drive electrical voltage input to the two piezoelectric layers. The stator is modeled as an annular laminated plate based on the classical plate theory and the governing equations are derived via Hamilton's variational principle. Variation of the free vibration characteristics as a function of several design parameters has been studied and based on this result, the forced vibration responses to the input electricity of various frequencies and magnitudes are investigated. The obtained results will provide an important criterion, a priori, in the design of piezoelectric motors.