• Journal of the Korean Wood Science and Technology
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• 제33권5호통권133호
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• pp.7-12
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• 2005

The objective of this study is to estimate the mechanical behavior in bending and the anatomical changes of wood under several deflection rates. Sample specimens of water-saturated Japanese cedar (Cryptomeria japonica) were stressed to rupture under several deflection rates. Mechanical properties of wood such as modulus of elasticity, modulus of rupture and stress at proportional limit, and anatomical changes affected by deflection rates were estimated. Microscopic observations on compression side of the test specimens when the specimen was loaded to rupture were carried out by the SEM (scanning electron microscopy). The results are summarized as follows: 1. The mechanical properties of wood were affected by variations of the deflection rates. The modulus of elasticity (MOE), modulus of rupture (MOR) and stress at proportional limit were in proportion to the logarithm of deflection rates. 2. The deflection of wood at rupture in bending increased as deflection rates decreased. 3. The variations of the microscopic deformations of sample specimens were closely related to the deflection of wood at rupture. In case of largely deflected wood by maximum bending load, severe and abundant microscopic deformations were observed.

• Computers and Concrete
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• 제17권3호
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• pp.295-304
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• 2016

An experimental investigation on the behaviour of concrete beams reinforced with various reinforcement, including ordinary steel bars, CFRP bars and CFRP prestressed concrete prisms(PCP). The main variable in the test program was the level of prestress and the cross section of PCP.The modes of failure and the crack width were observed. The results of load-deflection and load-crack width characteristics were discussed. The results showed that the CFRP prestressed concrete prisms as flexural reinforcement of concrete beams could limit deflection and crack width under service load and PCP can overcome the serviceability problems associated with the low elastic modulus/strength ratio of CFRP.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.631-636
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• 2002

It is common in multistory flat-plate structures that newly cast slabs are supported by a number of previously cast floors. Then the weight of newly cast slabs is imposed on shored previously cast floors as load, and this load may be large as double as dead load. Because early-age construction loads cause large immediate deflection and creep deflection with cracks, this loads influence long-term behavior of slabs. In current provision, the minimum thickness is required to satisfy serviceability But this minimum thickness based on historical precedent is determined by span length, therefore the minimum thickness of current provision can not includes properly the effect of construction scheme including the number of shored floors and construction cycle. In the present study, a minimum thickness criterion, which includes the effect of concrete strength, geometry of slabs and construction scheme, was developed from computer-based iteration using deflection calculation procedure of current code method.

• Structural Engineering and Mechanics
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• 제4권4호
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• pp.397-413
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• 1996

In this paper the elastic post-buckling behaviour of plates under non-uniform compressive edge stress is investigated. The compatibility differential equations is first solved analytically and then an approximate solution of the equilibrium equation is obtained using the Galerkin method. Explicit expressions are derived for the load-deflection, ultimate strength and membrane stress distributions. Analytical effective width formulations, based on the characteristics of the stress field of the buckled plate, are proposed for this general loading condition. The predicted load-deflection expression is compared with independent test results. Results are also presented detailing the load-deflection behaviour and stress distribution for various aspect ratios.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1117-1122
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• 2003

The paper on table deflection by stop state and move speed at loaded load, and the table deflection measured of static load. It is developed program for Date correction of LSM(Least Square Method). We experimented the method as following. The first a Laser setting and scan Experimental device measured curvature radius, The second A center of measurement object and curvature radius taking of LSC.

• Structural Engineering and Mechanics
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• 제43권2호
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• pp.147-161
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• 2012

This paper presents a curvature method for analysis of beam-columns with different materials and arbitrary cross-section shapes and subjected to combined biaxial moments and axial load. Both material and geometric nonlinearities (the p-delta effect in this case) were incorporated. The proposed method considers biaxial curvatures and uniform normal strains of discrete cross-sections of beam-columns as basic unknowns, and seeks for a solution of the column deflection curve that satisfies force equilibrium conditions. A piecewise representation of the beam-column deflection curve is constructed based on the curvatures and angles of rotation of the segmented cross-sections. The resulting bending moments were evaluated based on the deformed column shape and the axial load. The moment curvature relationship and the beam-column deflection calculation are presented in matrix form and the Newton-Raphson method is employed to ensure fast and stable convergence. Comparison with results of analytic solutions and eccentric compression tests of wood beam-columns implies that this method is reliable and effective for beam-columns subjected to eccentric compression load, lateral bracings and complex boundary conditions.

• Steel and Composite Structures
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• 제46권2호
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• pp.195-202
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• 2023

Dynamic deflection analysis of sandwich beams with cellular core under thermal and pulse loads has been performed in the present article. The cellular core sandwich beam has two layers fortified by graphene oxide powder (GOP) which are micromechanically modeled by Halpin-Tsai formulation. The pulse load has blast type and is applied on the top side of sandwich beam. The system of equations has been developed based on higher-order beam theory and Ritz method. Then, they are solved in Laplace domain to derive the dynamic deflections. The dependency of beam deflection on temperature variation, GOP content, pulse load duration/location and core relative density has been studied in detail.

• 대한기계학회논문집
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• 제19권8호
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• pp.1889-1900
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• 1995

In this study, a large deflection analysis of a plane frame composed of a thin-walled tube in investigated. When bent, a thin-walled tube is usually controlled by local buckling and subsequent bending collapse of the section. So load resistance reaches the yield level in a thin-walled rectangular tube. This relationship can be divided into three regimes : elastic, post-buckling and crippling. In this paper, this relationship is theoretically presented to be capable of describing nonlinearities and a stiffness matrix is derived by introducing a compound beam-spring element. A numerical analysis uses a constant incremental energy method and the solution is obtained by modifying stiffness matrix at elastic/inelastic stage. This analytical results, load-deflection paths show a good agreement with the test results.

• 한국공작기계학회논문집
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• 제13권6호
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• pp.41-47
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• 2004

This study is aimed to measure the deflection of loaded table on machine tool. The deflection rate is measured then the table is in a stationary state and is moved. In conclusion we have found that the more load increases, the more the table deflections. Also, we have found that the deflection rate increases in accordance with the speed of movement. Therefore, we have concluded that inspection of machine tool should be done considering the weight of load and the speed of movement. However, since the condition of accuracy test for domestic brand of machine tool is defined as unloaded case, measures should be explored only for loaded case.

• Steel and Composite Structures
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• 제11권3호
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• pp.225-232
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• 2011

In this study, the deflection and deformation behaviours of IPN80 steel beam and column were investigated under the different industrial loads. Single-sided welds were applied to IPN80 steel beams using shielded metal arc (SMAW) and metal inert gas welding (MIG) method in the form of T-type. After that, the performance of SMAW and MIG welded joints were identified using beam bending test under 500 and 3000 N loads. SMAW and MIG methods were compared with each other to understand the deflection and deformation behaviours of the welded steel structures. Lower deformation and deflection were obtained in MIG welded steel beams. The results show that, steel beams welded MIG method has higher load capacity than SMAW welded ones. MIG welding method is more reliable than the SMAW method for the combining performance and load capacity.