• Structural Monitoring and Maintenance
• /
• v.7 no.2
• /
• pp.85-107
• /
• 2020

Dynamic responses of porous piezoelectric and metal foam nano-size plates have been examined via a four variables plate formulation. Diverse pore dispersions named uniform, symmetric and asymmetric have been selected. The piezoelectric nano-size plate is subjected to an external electrical voltage. Nonlocal strain gradient theory (NSGT) which includes two scale factors has been utilized to provide size-dependent model of foam nanoplate. The presented plate formulation verifies the shear deformations impacts and it gives fewer number of field components compared to first-order plate model. Hamilton's principle has been utilized for deriving the governing equations. Achieved results by differential quadrature (DQ) method have been verified with those reported in previous studies. The influences of nonlocal factor, strain gradients, electrical voltage, dynamical load frequency and pore type on forced responses of metal and piezoelectric foam nano-size plates have been researched.

• Geomechanics and Engineering
• /
• v.29 no.6
• /
• pp.667-681
• /
• 2022

This paper presents a thermoelastic analysis of variable thickness plates made of functionally graded materials (FGM) subjected to mechanical and thermal loads. The thermal load is applied to the plate as a temperature difference between the top and bottom surfaces. Temperature distribution in the plate is obtained using the steady-state heat equation. Except for Poisson's ratio, all mechanical properties of the plate are assumed to vary linearly along the thickness direction based on the volume fractions of ceramic and metal. The plate is resting on an elastic foundation modeled based on the Winkler foundation model. The governing equations are derived based on the third-order shear deformation theory (TSDT) and are solved numerically for various boundary conditions using the differential quadrature method (DQM). The effects of various parameters on the stress distribution and deflection of the plate are investigated such as the value of thermal and mechanical loads, volume fractions of ceramic and metal, and the stiffness coefficients of the foundation.

• Journal of Welding and Joining
• /
• v.6 no.1
• /
• pp.21-27
• /
• 1988

This paper describes weldability of dissimilar metal plates with YAG laser for the use of a small-size electronic spring parts. Effects of welding conditions, combination of plates, thickness of upper plate are examined in relation to welding strength and microstructure of welded region. The obtained results are summarized as follows. Welding defects such as cavity and crack showed a tendency to easily occur in the case where 1) pulse duration is short, 2) laser power is high, 3) PBS plate with high thermal diffusivity is used for lower plate. Among these defects, the occurrence of cavity cased a drop of welding strength. This results from the reduction of welding area between upper and lower plates. In SK-5/SUS304 plates (thickness: 0.2/0.4mm/, welding strength was the highest in welding conditions: laser power is 30J/pulse, pulse duration 9ms, amount of defocus +2mm.

• Proceedings of the KIEE Conference
• /
• 1989.07a
• /
• pp.333-334
• /
• 1989

Electrically active part of the piezoelectric sound element is a ceramic thin circular disk cemented to a metal base plate (using a type of thermosetting epoxy). The active part is a thin lead zirconate titanate disk (PZT). The piezoelectric sound element is so dimensioned that its basic resonance frequency is approximately if the center of the audible frequency band: This frequency is mainly determined by the geometry and the sort of the metal base plate materials. In this study, four kinds of PZT ceramic and two classes of thin metal base plate were prepared. It is observed that dielectric and pizoelectric properties relate to acoustical properties (particularly sound pressure level).

• Journal of Korean Society of Steel Construction
• /
• v.8 no.3 s.28
• /
• pp.67-78
• /
• 1996

This paper provides the results of a study on the structural behavior of the composite slabs using the metal form deck plate. Cold-formed steel deck sections are used in many composite floor slab applications wherein the steel deck serves not only as the form for the concrete during construction but also as the principal tensile reinforcement for the bottom fiber of the composite slab. A total of 16 specimens are tested to clarify the composite action between the concrete and metal deck plate and to find the method to increase the composite effect, whether or not non-slip bars are used. The test results are summarized for the shear-bond capacities, deformation capacities, and failure modes for the specimens.

• Journal of Biomedical Engineering Research
• /
• v.43 no.2
• /
• pp.116-123
• /
• 2022

This study analyzes the Mechanical properties of a medical bone plate by 3D printing. With the recent development of 3D printing technology, it is being applied in various fields. In particular, in the medical field, the use of 3D printing technology, which was limited to the existing orthosis and surgical simulation, has recently been used to replacement bones lost due to orthopedic implants using metal 3D printing. The field of application is increasing, such as replacement. However, due to the manufacturing characteristics of 3D printing, micro pores are generated inside the metal printing output, and it is necessary to reduce the pores and the loss of mechanical properties through post-processing such as heat treatment. Accordingly, the purpose of this study is to analyze the change in mechanical performance characteristics of medical metal plates manufactured by metal 3D printing under various conditions and to find efficient metal printing results. The specimen to be used in the experiment is a metal plate for trauma fixation applied to the human phalanx, and it was manufactured using the 'DMP Flex 100(3D Systems, USA), a metal 3D printer of DMLS (Direct Metal Laser Sintering) method. It was manufactured using the PBF(Powder Bed Fusion) method using Ti6Al4V ELI powder material.

• Advances in Computational Design
• /
• v.1 no.2
• /
• pp.139-154
• /
• 2016

The usage of sandwich structure is extensively increasing in lightweight protective structures due to its low density and other useful properties. Sandwich panels made of metal sheets with unfilled cellular cores are found to exhibit lower deflections by comparing to an equivalent monolithic plate of same metal and similar mass per unit density. However, the process of localized impact on solid structures involving plastic deformation, high strain rates, temperature effect, material erosion, etc. does not hold effectively as that of monolithic plate. In present work, the applications of the sandwich plate with corrugated core have been extended to develop optimized lightweight armour using foam as medium of its core by explicit finite element analysis (FEA). The mechanisms of hardened steel projectile penetration of aluminum corrugated sandwich panels filled with foams have been numerically investigated by finite element analysis (FEA). A comparative study is done for the triangular corrugated sandwich plate filled with polymeric foam and metallic foam with different densities in order to achieve the optimum penetration resistance to ballistic impact. Corrugated sandwich plates filled with metallic foams are found to be superior when compared to the polymeric one. The optimized results are then compared with that of equivalent solid and unfilled cores structure to observe the effectiveness of foam-filled corrugated sandwich plate which provides an effective resistance to ballistic response. The novel structure can be the alternative to solid aluminum plate in the applications of light weight protection system.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.32 no.3
• /
• pp.222-225
• /
• 2006

The treatment objective of mandibular fracture is a return to normal function. According to Champy, a rigid fixation of mandibular angle fracture is performed by using 4 or 6 holes titanium miniplates on the external oblique ridge of mandible. However, the limitations of metal plate such as hypersensitivity, interference with the cranio-facial growth of growing child, secondary bone resorption around the plate, foreign body reaction, declination of primary callus formation, and bone atrophy due to the lack of normal stress reaction of the bone have been reported. Recently, biodegradable miniplate has been introduced and used as an alternative to the metal plate despite its lower strength than that of the titanium plate and the side effect caused by the resorption in the body. In this study, 61 patients diagnosed as mandibular angle fracture and treated from Jan. 1998 to Dec. 2004 in our department have been reviewed. Metal plate fixation was used in 50 patients and biodegradable plate fixation in 11 patients on the external oblique ridge around the fractured mandibular angle according to the principle of monocortical osteosynthesis by Champy. We compared the incidence of side effects and the degree of bony union at the mandibular inferior border in two different fixation methods. In conclusion, we have found that one miniplate regardless of matter could provide enough strength to grasp bony fragments of the tension site and compress the inferior border of mandible without any complications.

• 한국신재생에너지학회:학술대회논문집
• /
• 2006.11a
• /
• pp.352-355
• /
• 2006

As the stainless steel has good corrosion resistance, mechanical property and ease of manufacture, it has been studied as the candidate material of metallic bipolar plate for automotive PIMFC. But, metal is dissolved under fuel cell operating conditions Dissolved ions contaminate a membrane electrode assembly (MEA) and, decrease the fuel cell performance. In addition, metal oxide formation on the surface of stainless steel increases the contact resistance in the fuel cell. These problems have been acted as an obstacle in the application of stainless steel to bipolar plate. Therefore, many kinds of coating technologies have been examined in order to solve these problems. In this study, stainless steel was coated in order to achieve high conductivity and corrosion resistance by several methods. Contact resistance was measured by using a tensile tester and impedance analyzer Corrosion characteristics of coated stainless steel were examined by Tafel-extrapolation method from the polarization curves in a solution simulating the anodic and cathodic environment of PEMFC. Fuel cell performance was also evaluated by single cell test. We tested various coated metal bipolar plate and conventional and graphite were also tested as comparative samples. In the result, coated stainless steel bipolar plate exhibited better cell performance than graphite to bipolar plate.

• Transactions of the Korean hydrogen and new energy society
• /
• v.21 no.4
• /
• pp.295-300
• /
• 2010

Metal bipolar plate applied to Polymer Electrolyte Membrane Fuel Cell is getting most attractive due to their good feasibility of mass production and low cost. But it is one of the immediate causes of performance decline because it is difficult to reduce channel pitch of metal bipolar plate. In this study, mesh was inserted in between bipolar plate and GDL to obtain uniform contact pressure without reducing channel pitch. The section measuring and performance test were carried out to confirm the mesh structure distributes contact pressure equally in reacting area. The performance of 3 type mesh structures developed in this study were higher than the normal cell at all over the current range. Especially, it showed that the mesh cell performance was increased and pressure drop was decreased with diminishing mesh gap size. The Mesh structure was more sensitive to humidification and contact pressure change than the normal cell.