• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2002년도 가을 학술발표회 논문집
• /
• pp.435-442
• /
• 2002

In a multicell box structure, distortional warping normal stress due to warping of cross section and transverse bending normal stress of walls due to distortion of cross section may consider as significant stresses unless distortion of box section is appropriately restricted. Nevertheless, during the past decades, no evaluation of distortional warping and transverse bending resistances for the multicell box section has been performed owing to geometric complexity and Insufficient information with respect to the distortion of multicell box section. The objective of present study is to evaluate the distortional warping and transverse bending resistances for the distortion of multicell box section and to validate the resistances through box girder analyses using multicell box beam element developed and conventional shell element. This developed box beam element has nine degrees of freedom per node including the effect of distortion.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2001년도 봄 학술발표회 논문집
• /
• pp.325-332
• /
• 2001

Due to the rapidly developing computer technique, bridges can be modeled by using grillage method for analyzing the girder, or FEM for more accrute and detailed analysis. If the cells of multicellular decks are stiffened with diaphrams or cross-bracing at frequent intervals, to prevent them changing shape by distortion, the deck can be analysed like a beam if it is narrow, or like slab if it is wide. However it is often convenient and acceptable to use cellular structures and box-girders which do distort under shear and torsional loading, and it is then necessary to take account of the distortion in the method of calculation. But plane grillage method cannot cosider effect of distortion and FEM is non-economical because it is not easy to modeling and needs lots of time. So, this study suggests the Shear-flexible Grillage which reproduces the distortion behaviour of the cells.

• Macromolecular Research
• /
• 제17권10호
• /
• pp.797-806
• /
• 2009

The mechanical and thermal behaviors of polyamide-6/clay nanocomposites were studied using the continuum-based, micromechanical models such as Mori-Tanaka, Halpin-Tsai and shear lag. Mechanic-based model prediction provides a better understanding regarding the dependence of the nanocomposites' reinforcement efficiency on conventional filler structural parameters such as filler aspect ratio ($\alpha$), filler orientation (S), filler weight fraction (${\Psi}_f$), and filler/matrix stiffness ratio ($E_f/E_m$). For an intercalated and exfoliated nanocomposite, an effective, filler-based, micromechanical model that includes effective filler structural parameters, the number of platelets per stack (n) and the silicate inter-layer spacing ($d_{001}$), is proposed to describe the mesoscopic intercalated filler and the nanoscopic exfoliated filler. The proposed model nicely captures the experimental modulus behaviors for both intercalated and exfoliated nanocomposites. In addition, the model prediction of the heat distortion temperature is examined for nanocomposites with different filler aspect ratio. The predicted heat distortion temperature appears to be reasonable compared to the heat distortion temperature obtained by experimental tests. Based on both the experimental results and model prediction, the reinforcement efficiency and heat resistance of the polyamide-6/clay nanocomposites definitely depend on both conventional (${\alpha},\;S,\;{\Psi}_f,\;E_f/E_m$) and effective (n, $d_{001}$) filler structural parameters.

• 한국의상디자인학회지
• /
• 제22권3호
• /
• pp.63-74
• /
• 2020

Modern clothes are part of formative arts and express experimentation and originality. This tendency is especially prominent in structural fashion. This study set out to analyze structural fashion in various aspects, examining and analyzing the expressive and formative characteristics of Deformation and contribute to the development of creative fashion design. The approach of peer debriefing was used with three fashion experts to identify structural clothes in the women's haute couture collections from a total of 24 seasons from S/S of 2008 to F/W of 2019. The clothes with Deformation characteristics were then identified to analyze expressive and formative characteristics. The expressive characteristics of Deformation in structural clothes were exaggeration, distortion, and recombination. Exaggeration was expressed with exaggerated sizes, forms, and excessive use. Distortion was expressed with distorted forms and functions and through optical illusions. Recombination was expressed with the recombination of forms and roles. The formative characteristics of Deformation were maximum, playfulness, and unfamiliarity. The study connected the expressive characteristics to the formative ones and examined them simultaneously, finding that "distortion" and "playfulness" represented the expressive and formative characteristics, respectively. The characteristics of Deformation are expressed in various ways in structural fashion. If they are considered, they will make valuable contributions to creative ideas.

• The Korean Journal of Ceramics
• /
• 제6권1호
• /
• pp.9-14
• /
• 2000

Glass transition temperature (T/sub g/) is proportional to the quadrupole splitting(Δ) of Fe(III) obtained from the /sup 57/Fe Mossbauer spectra (T/sub g/-Δ rule (1990)). The values of Δ reflect the distortion of Fe(III) atoms, which occupy the sites of network-forming atoms. Heat treatment of potassium vanadate and calcium gallate glasses at around the individual T/sub g/ causes a structural relaxation, accompanying a linear decrease of T/sub g/ and Δ values. These experimental results prove that T/sub g/ decreases with a decrease in the distortion of VO₄, GaO₄, and FeO₄tetrahedra, as the T/sub g/-Δ rule predicted.

• 한국위성정보통신학회논문지
• /
• 제5권1호
• /
• pp.75-79
• /
• 2010

인공위성 구조체는 궤도상에서 열하중으로 인하여 구조적인 변형을 일으키게 된다. 이로 인하여 구조체에 장착된 관측장비들은 지상에서 조립 시에 설정된 지향방향이 변화하게 되고 원하지 않는 방향으로 관측하는 문제점이 발생한다. 위성의 관측성능이 높아질수록 성공적인 관측임무를 수행하기 위해서는 열변형에 의한 지향방향의 변화량은 줄어들어야 한다. 본 논문에서는 지구궤도 위성에 대하여 열변형 해석을 수행하여 지향오차를 예측하는 방법 및 결과에 대하여 기술한다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제10권1호
• /
• pp.257-271
• /
• 2016

The Structural SIMilarity (SSIM) index is one of the most widely-used methods for perceptual image quality assessment (IQA). It is based on the principle that the human visual system (HVS) is sensitive to the overall structure of an image. However, it has been reported that indices predicted by SSIM tend to be biased depending on the type of distortion, which increases the deviation from the main regression curve. Consequently, SSIM can result in serious performance degradation. In this study, we investigate the aforementioned phenomenon from a new perspective and review a constant that plays a big role within the SSIM metric but has been overlooked thus far. Through an experimental study on the influence of this constant in evaluating images with SSIM, we are able to propose a new solution that resolves this issue. In the proposed IQA method, we first design a system to classify different types of distortion, and then match an optimal constant to each type. In addition, we supplement the proposed method by adding color perception-based structural information. For a comprehensive assessment, we compare the proposed method with 15 existing IQA methods. The experimental results show that the proposed method is more consistent with the HVS than the other methods.

• Journal of Welding and Joining
• /
• 제31권6호
• /
• pp.107-111
• /
• 2013

The welding distortion is caused by welding heat in the structures which are widely used in shipbuilding and automotive industries, thus many researchers have proposed such methods to control the welding distortion through trials and numerical studies. The welding distortion has been the main cause of low productivity due to the structural strength degradation, apparent flaw, additional deformation caused by the process followed the current assembly step, and the increase of correction workload. The deformation of fillet welding is investigated in this study, and the influence of the rib height on the welding distortion is verified through the actual experiment. And the numerical analysis model using the FE software MSC.marc for analysis of welding distortion is proposed.

• 한국생산제조학회지
• /
• 제20권3호
• /
• pp.310-315
• /
• 2011

General portal machine represents a distinct weak spot concerning their structural behavior because of long protruding structure components, such as saddles and rams. The weak point causes the deformation of the machine tool and consequently rises a severe machining error. The purpose of this study is to improve the structural design of crossrail in order to minimize it's distortion. Tool Center Point (TCP) was chosen as a reference point for evaluating the distortion effect of a crossrail and topological optimization was adopted as a method of structural design improvement. The displacements of TCP according to the machining positions were investigated by structural analyses for both of original crossrail design and the improved one. The comparing results showed that the displacement of TCP could be reduced about 55% maximum.

• 대한전기학회논문지:시스템및제어부문D
• /
• 제52권7호
• /
• pp.434-441
• /
• 2003

This paper proposes a new quantitative and objective image quality metric which is essential to verify the performance of block-based DCT image coding. The proposed metric considers not only global distortion of coded image such as spatial frequency sensitivity and channel masking using HVS based multi-channel model, but also structural distortions caused block-based coding. The experimental results show a strong correlation between proposed metric and subjective metric.