• Computational Structural Engineering
• /
• v.1 no.2
• /
• pp.83-90
• /
• 1988

The present work is concerned with the improvement of finite element for the analysis of plate bending structures. The element formulation is based upon Mindlin plate concept. The displacement field of this element is formed by adding nonconforming modes to two rotational displacement components of a 'heterosis plate element. The element has the requisite numbers of zero eigenvalues associated with rigid body modes to avoid the spurious zero energy mode. It is shown that the results obtained by the element converged to the exact solutions very rapidly as the mesh is refined and exhibited reliable solutions through numerical studies for standard benchmark problems. This element is shown to overcome the shear locking problem completely in very thin plate situation even for irregular meshes.

• Structural Engineering and Mechanics
• /
• v.24 no.2
• /
• pp.227-245
• /
• 2006

The performance of a three dimensional non-linear finite element model for hyperelastic material considering the effect of compressibility is studied by analyzing rubber blocks under different modes of deformation. It includes simple tension, pure shear, simple shear, pure bending and a mixed mode combining compression, shear and bending. The compressibility of the hyperelastic material is represented in the strain energy function. The nonlinear formulation is based on updated Lagrangian (UL) technique. The displacement model is implemented with a twenty node brick element having u, ${\nu}$ and w as the degrees of freedom at each node. The results obtained by the present numerical model are compared with the analytical solutions available for the basic modes of deformation where the agreement between the results is found to be satisfactory. In this context some new results are generated for future references since the number of available results on the present problem is not sufficient enough.

• Steel and Composite Structures
• /
• v.6 no.4
• /
• pp.319-333
• /
• 2006

A rectangular plate made of a porous material is the subject of the work. Its mechanical properties vary continuously on the thickness of a plate. A mathematical model of this plate, which bases on nonlinear displacement functions taking into account shearing deformations, is presented. The assumed displacement field, linear geometrical and physical relationships permit to describe the total potential energy of a plate. Using the principle of stationarity of the total potential energy the set of five equilibrium equations for transversely and in-plane loaded plates is obtained. The derived equations are used for solving a problem of a bending simply supported plate loaded with transverse pressure. Moreover, the critical load of a bi-axially in-plane compressed plate is found. In both cases influence of parameters on obtained solutions such as a porosity coefficient or thickness ratio is analysed. In order to compare analytical results a finite element model of a porous plate is built using system ANSYS. Obtained numerical results are in agreement with analytical ones.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.2 no.6
• /
• pp.66-75
• /
• 1994

In this paper, the effects of temperature change on the impact damages of CF/PEEK laminates are experimentally investigated. Composite laminates used in this experiment are CF/PEEK orthotropic laminated plates, which have two-interfaces$[0^{\circ}_4/90^{\circ}_4]_{9+} A steel ball launched by the air gun collides against CFRP laminates to generate impact damage. The delamination damages are oberved by a scanning acoustic microscope. And various relations are experimentally observed including the impact energy vs. delamination area, the specimen temperature vs. transverse crack, and the impact energy vs. residual bending strength of carbon fiber peek composite laminates subjected to FOD(Foreign Object Damage) under high temperatures.

• Steel and Composite Structures
• /
• v.44 no.1
• /
• pp.1-15
• /
• 2022

The weld quality has always been an important factor affecting the development of exposed CFT column-base joint. In this paper, a new type of exposed RCFST column-base joint is proposed, in which the high strength steel bars (USD 685) are set through the column and reinforced concrete foundation without any base plate and anchor bolts. Three specimens, the varying axial force ratio (0, 0.25 and 0.5), were tested under cyclic loadings. In addition, the bending moment capacity, energy dissipation capacity and deformation capacity of column-base joints were clarified. The experimental results indicated that the axial force ratio increases the stiffness and the bending moment and improves the energy dissipation capacity of column-base joints. This is because a large axial force can limit the slip between steel tubular and infilled concrete effectively. The specimens show stable hysteresis behavior.

• Journal of the Korea Convergence Society
• /
• v.8 no.3
• /
• pp.185-190
• /
• 2017

This study investigates the bending stress, shear stress and deformation energy happening at the inner fiber structure when the bending moment is applied to he specimen with flat shape composed of carbon fiber. As CFRP is composed of innumerable fibers with multi-axes, the stress under bending condition can be effectively distributed. Theses stresses is shown to increase again at the starting point as this angle of $60^{\circ}$. Therefore, the condition at the stacking angle of $60^{\circ}$ is seen to become most adequate under the state where the bending stress happens. On the basis of this study result, the damage property by the bending at the plate due to stacking angle was examined through the analytic approach. it is thought that this study can be devoted to the safe design for damage prevention and durabilty improvement. Also, the esthetic sense can be shown as the designed factor of shape with flat plate is grafted onto the convergence technique.

• Journal of Dental Anesthesia and Pain Medicine
• /
• v.21 no.2
• /
• pp.139-153
• /
• 2021

Background: In anesthetic techniques, touching bones can cause needle bending. Theoretically, a needle should support such deflection without fracturing. However, it is possible that a needle may fracture depending on the quality and type of needle used. This study evaluated the physical, chemical, and micromorphological characteristics of long and short dental anesthetic needles, as well as the mechanical properties of flexural load and bending resistance when needles are subjected to different bending angles. Methods: Long and short needles (30G, Jets, Misawa, Selekto, Terumo, Unoject and 27G, Dencojet, Injex, Jets, Misawa, Procare, Setoject XL, Terumo) were evaluated. Scanning electron microscopy was used to evaluate the needle bevels and energy-dispersive X-ray spectroscopy was used for the chemical analysis of needle compositions. Flexural loading and bending strength assessments were performed using a universal testing machine by bending the needles (n = 5) to angles of 30°, 60°, or 90°, or until fracture occurred. Results: The Injex 27G, Jets 27G, and Septoject XL 27G needles were all less than 30 mm in length. There were small percentage variations in the chemical compositions of the needles. Superior smoothness was observed for the Unoject 30G needle, which exhibited the highest fracture resistance at 60°. The Jets 30G needle exhibited greater resistance to fractures at 90°. The Procare 27G needle exhibited the highest load resistance to bending, followed by the Septoject XL 27G needle, and both needles were tied for the lowest fracture resistance. No needle fractured when bent to 30° or at less than three bends to 60° or 90°. Conclusions: Greater needle resistance to bending increases the probability of early fracturing. Thinner and shorter needles are more resistant than longer and thicker needles. Performing a single bend does not result in any significant risk of fracture or obliterate the lumen, allowing for the continued passage of anesthetic liquid.

• Journal of the Korea Convergence Society
• /
• v.13 no.3
• /
• pp.197-202
• /
• 2022

The CZTS solar cell is a thin film solar cell using an absorption layer composed of Cu, Zn, Sn, Se, and S, and is cheaper than a CIGS solar cell using In and Ga and more eco-friendly than a perovskite and CdTe solar cell using Pb and Cd. In this study, we conducted a bending test for flexible CZTS solar cells. Experiments were conducted in the direction of inner benidng with compressive stress and outer bending with tensile stress, and during the number of bending 1,000 times with a radius of curvature of 50 mmR, the efficiency of the solar cell decreased by up to 12.7%, and the biggest cause of efficiency reduction in both directions was a large decrease in parallel resistance.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.19 no.1
• /
• pp.47-51
• /
• 2016

It has made a special study of bending behavior of F.R.P. sandwich beams with bonded 2nd-reinforced plies. Specimen's faces were made of chopped mat 300-450, roving clothes 570, core is urethane foam, resin is 713bp unsaturated polyester for ship construction and the mixture weight ratio of resin versus fiber was 55:45 for bending analysis. The purpose of this paper is to study the exact bending behavior of bonded area's deflection and stiffness depends upon various bonded F.R.P. (2nd reinforced ply) length and thickness on which covered joints and to find the optimum design for the sandwich structures. All results and suggestions are based on experiment and using thick face calculation.

• Journal of Fashion Business
• /
• v.12 no.6
• /
• pp.61-72
• /
• 2008

The UV-protection effect of green-tea dyed fabrics was reported in our previous studies. The chitosan was used as a natural mordant of cellulose fiber for green tea extract because chitosan is a natural bio-polymer. The increase in the UV protection property of summer cellulose fabrics, cotton and linen, upon the repetition of chitosan mordanting and green tea dyeing was observed. However, the physical property change would be followed by this repeated wet processing of the cellulose fabric. Therefore, the physical changes of the chitosan mordanted and green tea dyed cotton and linen fabrics were evaluated by KES-FB system. Tensile, shear, bending, compression, and surface characteristics were tested upon the repetition of mordanting and dyeing treatments. Linearity of tensile force increased in the treated cotton and linen samples. Tensile energy and resilience decreased in all treated fabrics. Shear stiffness increased in the treated cotton and linen in general. Shear hysteresis was increased in all cotton samples and some linen samples. In cotton, the bending rigidity in all treated cottons increased except C3G3. As the chitosan mordanting numbers increased, the bending rigidity tended to decrease. In linen, the bending rigidity and hysteresis increased in all treated samples. Compressional energy and resilience increased as the number of chitosan mordanting increased both in cotton and linen. This could be the result of the increase in thickness upon chitosan mordanting. Surface coefficient of friction increased in the treated cotton and linen in general. Surface roughness tended to increase in cotton.