• Structural Engineering and Mechanics
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• 제56권5호
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• pp.767-785
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• 2015

The stochastic finite element method is employed to obtain a stochastic dynamic model of angled beams subjected to impact loads when uncertain material properties are described by random fields. Using the perturbation technique in conjunction with a precise time integration method, a random analysis approach is developed for efficient analysis of random elastic waves. Formulas for the mean, variance and covariance of displacement, strain and stress are introduced. Statistics of displacement and stress waves is analyzed and effects of bend angle and material stochasticity on wave propagation are studied. It is found that the elastic wave correlation in the angled section is the most significant. The mean, variance and covariance of the stress wave amplitude decrease with an increase in bend angle. The standard deviation of the beam material density plays an important role in longitudinal displacement wave covariance.

• 한국농공학회논문집
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• 제64권4호
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• pp.45-53
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• 2022

In this study, the loading test and structural analysis were performed on the snow load and the results were compared. The load plates were loaded on the roof surface of the model, and structural analysis was performed under the same conditions. The result of loading test, the maximum displacement was observed in the center of the top, and the maximum stress was observed near the bottom point. Displacement and stress were found to have a high linear relationship with the load. Comparing the structural analysis results with the loading test results, the maximum displacement difference is 4.5% and the maximum stress difference is 10.2%. It is expected that closer results can be derived if the boundary conditions for the longitudinal direction of the model are clarified during experiments and analysis.

• The Journal of Advanced Prosthodontics
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• 제10권2호
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• pp.138-146
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• 2018

PURPOSE. The purpose of this study was to analyze the effects of the splinted implant prosthesis in a reconstructed mandible using three-dimensional finite element analysis. MATERIALS AND METHODS. Three-dimensional finite element models were generated from a patient's computed tomography data. The patient had undergone partial resection of the mandible that covered the area from the left canine to the right condyle. The mandible was reconstructed using a fibula bone graft and dental implants. The left mandibular premolars and molars remained intact. Three types of models were created. The implant-supported prosthesis was splinted and segmented into two or three pieces. Each of these models was further subcategorized into two situations to compare the stress distribution around normal teeth and implants. Oblique loading of 300 N was applied on both sides of the mandible unilaterally. The maximum von Mises stress and displacement of the models were analyzed. RESULTS. The stress distribution of the natural mandible was more uniform than that of the reconstructed fibula. When the loading was applied to the implant prosthesis of reconstructed fibula, stress was concentrated at the cortical bone around the neck of the implants. The three-piece prosthesis model showed less uniform stress distribution compared to the others. Displacement of the components was positively correlated with the distance from areas of muscle attachment. The three-piece prosthesis model showed the greatest displacement. CONCLUSION. The splinted implant prosthesis showed a more favorable stress distribution and less displacement than the separated models in the reconstructed mandible.

• Structural Engineering and Mechanics
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• 제7권2호
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• pp.203-216
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• 1999

A previously proposed finite element formulation method is refined and modified to generate a new type of elements. The method is based on selecting a set of general solution modes for element formulation. The constant strain modes and higher order modes are selected and the formulation method is designed to ensure that the element will pass the basic single element test, which in turn ensures the passage of the basic patch test. If the element is to pass the higher order patch test also, the element stiffness matrix is in general asymmetric. The element stiffness matrix depends only on a nodal displacement matrix and a nodal force matrix. A symmetric stiffness matrix can be obtained by either modifying the nodal displacement matrix or the nodal force matrix. It is shown that both modifications lead to the same new element, which is demonstrated through numerical examples to be more robust than an assumed stress hybrid element in plane stress application. The method of formulation can also be used to arrive at the conforming displacement and hybrid stress formulations. The convergence of the latter two is explained from the point of view of the proposed method.

• Tribology and Lubricants
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• 제23권3호
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• pp.89-94
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• 2007

The stress and displacement behavior analysis of an aluminum tube for an organic photo conductor drum has been presented using a finite element analysis technique by non-linear FEM program. The maximum displacement in the radial direction of OPC drum may directly affect to the quality of printed matter. Thus, the deformed profile of the aluminum tubes should be limited depending on the toner powder size and the contact rolling forces between an OPC drum and a paper. This paper recommends the critical loading of 400 Pa for the provided toner size, $8{\mu}m$ for excellent printed matters and long life of the toner cartridge.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제25권2호
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• pp.54-65
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• 2021

In this study, a two-dimensional thermoelastic problem under hyperbolic heat conduction theory with an internal heat source is considered. The general solution for the temperature field, stress components and displacement field are obtained using the reduced differential transform method. The stress and displacement components are obtained using the thermal stress function in the reduced differential transform domain. All the solutions are obtained in the form of power series. The special case with a time-dependent laser heat source has been considered. The problem is considered for homogeneous material with finite rectangular cross-section heated with a non-Gaussian temporal profile. The effect of the heat source on all the characteristics of a material is discussed numerically and graphically for magnesium material taking a pulse duration of 0.2 ps. This study provides a powerful tool for finding the solution to the thermoelastic problem with less computational work as compared to other methods. The result obtained in the study may be useful for the investigation of thermal characteristics in engineering and industrial applications.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2050-2054
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• 2007

This study numerically and experimentally investigated on thermal strain analysis of aluminum alloy casting mold using metal foundry. To predict the numerical result of thermal strain in Al alloy casting mold during the cooling process, it is performed the investigation of temperature distribution, stress and displacement based on the physical properties of Al alloy. In results of this study, Al alloy casting mold represented rapidly cooling graph during initial 20minutes after beginning cooling process, therefore value of stress and displacement is rapidly changed during initial 20minutes after beginning cooling process. In addition to, temperature distribution obtained by experiment confirmed corresponding pattern then compared numerical analysis with experiment. These results are distribute to make the effective and the high precision casting mold.

• 대한기계학회논문집
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• 제18권11호
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• pp.2871-2882
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• 1994

Two kinds of 4-node plane stress/strain finite elements are presented in this work. They are derived from the modified Hellinger-Reissner variational principle so as to employ the internal incompatible displacement and independent stress fields, or the incompatible displacement and strain fields. The introduced incompatible functions are selected to satisfy the constant strain condition. The elements are evaluated on several problems of bending and material incompressibility with regular and distorted elements. The results show that the new elements perform excellently in the calculation of deformation and stresses.

• Journal of Welding and Joining
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• 제15권1호
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• pp.55-65
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• 1997

The stress intensity factor has been calculated for the cracked plate subjected to remote normal stress and reinforced with a plate by symmetric spot welding. The solution was based on displacement compatibility condition between the cracked sheet and the reinforcement plate. It is shown that the results from the derived equation for stress intensity factor were agreed with previous solutions. The reinforcement effect gets better as a joining spot is closer to the crack tip and the other joining spots become nearer to the crack surface.

• 한국세라믹학회지
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• 제31권12호
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• pp.1449-1458
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• 1994

A new analytical model which can discribe the relationship between the bridging stress and the crack opening displacement was proposed to investigate the microstructural effect on the R-curve behavior in a polycrystalline alumina. The crack opening displacement according to the distance behind the stationary crack tip was measured using in-situ fracture technique in an SEM, and then used for a fitting procedure to obtain the distribution of bridging stress. The current model and an empirical power law relation were introduced into the fitting procedure. The results indicated that the bridging stress function and R-curve computed by the current model were consistent with those computed by the power law relation. The microstructural factor, e.g., the distribution of grain size, was also found to be closely related to the bridging stress. Thus, this model explained well the interaction effect between the distribution of bridging stress and the local-fracture-controlling microstructure, providing important information for the systematic interpretation of microfracture mechanism including R-curve behavior of a monolithic alumina.