• Structural Engineering and Mechanics
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• v.72 no.2
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• pp.229-244
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• 2019

Weak form integral equations are developed to investigate the flapwise bending vibration of the rotating beams. Rayleigh and Eringen nonlocal elasticity theories are used to investigate the rotatory inertia and Size-dependency effects on the flapwise bending vibration of the rotating cantilever beams, respectively. Through repetitive integrations, the governing partial differential equations are converted into weak form integral equations. The novelty of the presented approach is the approximation of the mode shape function by a power series which converts the equations into solvable one. Substitution of the power series into weak form integral equations results in a system of linear algebraic equations. The natural frequencies are determined by calculation of the non-trivial solution for resulting system of equations. Accuracy of the proposed method is verified through several numerical examples, in which the influence of the geometry properties, rotatory inertia, rotational speed, taper ratio and size-dependency are investigated on the natural frequencies of the rotating beam. Application of the weak form integral equations has made the solution simpler and shorter in the mathematical process. Presented relations can be used to obtain a close-form solution for quick calculation of the first five natural frequencies of the beams with flapwise vibration and non-local effects. The analysis results are compared with those obtained from other available published references.

• Interaction and multiscale mechanics
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• v.1 no.3
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• pp.329-337
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• 2008

This paper presents the derivation of the generalized governing equations in theory of elasticity, their weak forms and the some applications in the numerical analysis of structural mechanics. Unlike the differential equations in classical elasticity theory, the generalized equations of the equilibrium and compatibility equations presented here take the form of integral equations, and the generalized equilibrium equations contain the classical differential equations and the boundary conditions in a single equation. By using appropriate test functions, the weak forms of these generalized governing equations can be established. It can be shown that various variational principles in structural analysis are merely the special cases of these weak forms of generalized governing equations in elasticity. The present weak forms of elasticity equations extend greatly the choices of the trial functions for approximate solutions in the numerical analysis of various engineering problems. Therefore, the weak forms of generalized governing equations in elasticity provide a powerful modeling tool in the computational structural mechanics.

• Structural Engineering and Mechanics
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• v.11 no.2
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• pp.221-236
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• 2001

A local point interpolation method (LPIM) is presented for the stress analysis of two-dimensional solids. A local weak form is developed using the weighted residual method locally in two-dimensional solids. The polynomial interpolation, which is based only on a group of arbitrarily distributed nodes, is used to obtain shape functions. The LPIM equations are derived, based on the local weak form and point interpolation. Since the shape functions possess the Kronecker delta function property, the essential boundary condition can be implemented with ease as in the conventional finite element method (FEM). The presented LPIM method is a truly meshless method, as it does not need any element or mesh for both field interpolation and background integration. The implementation procedure is as simple as strong form formulation methods. The LPIM has been coded in FORTRAN. The validity and efficiency of the present LPIM formulation are demonstrated through example problems. It is found that the present LPIM is very easy to implement, and very robust for obtaining displacements and stresses of desired accuracy in solids.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.138-139
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• 2022

Through previous studies, it was reviewed how to improve the insulation performance of weak areas by installing heated wires as a solution to the corners pointed out as weak areas when applying the insulation gang form and the existing pouring areas.

• Bulletin of the Korean Mathematical Society
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• v.45 no.3
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• pp.437-444
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• 2008

As a weak form of a subtraction algebra, the notion of weak subtraction algebras is introduced, and its examples are given. A method to make a weak subtraction algebra from a quasi-ordered set is provided.

• Journal of the Chungcheong Mathematical Society
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• v.29 no.2
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• pp.229-253
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• 2016

As a generalization of (i, j)-weakly m-continuous functions [43], we introduce the notion of weakly M(i, j)-continuous functions and obtain many characterizations and some properties of the functions. We show that the function is a unified form of some functions between m-spaces and certain kinds of weakly continuous functions in bitopological spaces.

• Bulletin of the Korean Mathematical Society
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• v.51 no.2
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• pp.567-577
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• 2014

In this note, we generalize the weak maximum principle in [4] to the case of complete linear Weingarten hypersurface in Riemannian space form $\mathbb{M}^{n+1}(c)$ (c = 1, 0,-1), and apply it to estimate the norm of the total umbilicity tensor. Furthermore, we will study the linear Weingarten hypersurface in $\mathbb{S}^{n+1}(1)$ with the aid of this weak maximum principle and extend the rigidity results in Li, Suh, Wei [13] and Shu [15] to the case of complete hypersurface.

• Korean Journal of Psychosomatic Medicine
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• v.4 no.2
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• pp.198-206
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• 1996

To assess premenstrual changes in adolescents, a self rating retrospective premenstrual assessment from(PAF) and a prospective daily rating form(DRF) were administered to 230 high school students who reported premenstrual changes. The results were as follows 1) According to typological categories of retrospective premenstrual assessment form, the most commonly reported changes in mood and behavior were major depressive syndrome(40.0%), impulsive syndrome(20.9%). Especially among the subtype of depressive syndrome, hostility feature and withdrawal feature were most frequent. The most commonly reported changes in physical condition were general discomfort(73.5%), fatigue(33.9%). 50.9% of all subjects reported impaired social function. 2) 41.2% of the subjects who met the criteria for typological categories of retrospective premenstrual assessment form were confirmed by prospective daily rating form. 3) According to different criteria of percent change method of assessing symptom change, 38.7% of all subjects had at least one mild premenstrual change and 23.5% had at least one moderate premenstrual change. 4) Using prospective daily rating form, overall psychological changes were confirmed more frequently than physical changes. Of the mild premenstrual changes, 'low energy, tired & weak', 'less or impaired work' were most common changes. Of the moderate premenstrual changes, the most common change was 'low energy, tired & weak'. 5) As attitude toward menstruation, 44.9% of the subjects with confirmed premenstrual changes had more negative attitude(disgusted) toward menstruation. 6) The subjects with confirmed mild or moderate premenstrual changes had only dysphoric mood changes or both physical and dysphoric mood changes, but did not have only physical changes. These results suggest that retrospective reports of premenstrual changes were partially confirmed by daily prospective ratings. A substantial number of adolescents appeared to experience premenstrual changes, and the most common confimed premenstrual change of mild or moderate severity was 'low energy, tired and weak'.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.6 no.1
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• pp.70-76
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• 2006

Some Stampacchia type of generalized weak vector quasivariational-like inequalities for fuzzy mappings was introduced and the existence of solutions to them under non-compact assumption was considered using the particular form of the generalized Ky Fan's section theorem due to Park [15]. As a corollary, Stampacchia type of generalized vector quasivariational-like inequalities for fuzzy mappings was studied under compact assumption using Ky Fan's section theorem [7].

• Communications of the Korean Mathematical Society
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• v.16 no.2
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• pp.291-296
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• 2001

For randomly indexed sums of the form (Equation. See Full-text), where {X(sub)ni, i$\geq$1, n$\geq$1} are random variables, {N(sub)n, n$\geq$1} are suitable conditional expectations and {b(sub)n, n$\geq$1} are positive constants, we establish a general weak law of large numbers. Our result improves that of Hong [3].