• Journal of Adhesion and Interface
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• v.3 no.1
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• pp.20-23
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• 2002

The wetting properties of an uncured epoxy resin on both clean and oiled, galvanised steel have been studied. Since the polymer is very viscous at ambient temperature, and also with an aim to simulate industrial conditions, the spreading of drops of resin during a heating cycle (temperature increase at $10^{\circ}C/min$) was recorded and analysed. On clean steel, a contact angle, ${\theta}$, vs time, t, plot shows sigmoidal behaviour, whereas on the oiled substrate, spreading almost ceases in an intermediate stage. This strange behaviour is attributed to significant oil absorption by the polymer.

• Proceedings of the KWS Conference
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• 1995.04a
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• pp.96-98
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• 1995

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.142-142
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• 2004

박막으로 표면처리한 다양한 강판이 자동차 차체와 부품, 가전제품 등의 제조를 위해 여러 가지 판재 성형공정에 적용되고 있으나, 제품 개발기간과 비용 감소, 성형과정에서 표면 코팅층의 특성 변화로 인해 성형성 열화와 성형불량을 줄이면서, 제품의 고정밀화, 고품질화를 실현하기 위해서는 코팅층에 대한 기계적 특성과 마찰거동을 명확히 규명하는 것이 반드시 필요하다 현재 나노 마이크로 수준인 코팅층의 기계적 물성치를 측정하기 위해 가장 널리 사용되는 방법은 나노 인덴테이션이다.(중략)

• Structural Engineering and Mechanics
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• v.15 no.3
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• pp.269-284
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• 2003

This paper reports a series of component tests on a lightweight floor system and a method to predict the natural frequency of the floor using a frame analysis program. Full-scale floor tests are also briefly described. DuraGal steel Rectangular Hollow Sections (in-line galvanised RHS) are used as joists, bearers and piers in DuraGal lightweight floor systems. A structural grade particleboard is used as decking. Connection stiffness between different components (bearer, joist, pier and floor decking) was determined. A 40% composite action was achieved between the RHS joist and the particleboard. Both 2D and 3D models were developed to study the effect of connection stiffness on predicting the natural frequency of DuraGal lightweight floor systems. It has been found that the degree of shear connection between the bearer and the joist has a significant influence on the floor natural frequency. The predicted natural frequencies are compared with measured values from full scale floor testing.

• Steel and Composite Structures
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• v.9 no.3
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• pp.239-253
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• 2009

This paper reviews the concept of tensegrity structures and proposes a new type of dismountable steel tensegrity grids for possible deployment as light-weight roof structures. It covers the fabrication of the prototype structures followed by their instrumentation, destructive testing and numerical analysis. First, a single module, measuring $1m{\times}1m$ in size, is fabricated based on half-cuboctahedron configuration using galvanised iron (GI) pipes as struts and high tensile stranded cables as tensile elements. Detailed instrumentation of the structure is carried out right at the fabrication stage. The structure is thereafter subjected to destructive test during which the strain and the displacement responses are carefully monitored. The structure is modelled and analyzed using finite element method (FEM) and the model generated is updated with the experimental results. The investigations are then extended to a $2{\times}2$ grid, measuring $2m{\times}2m$ in size, fabricated uniquely by the cohesive integration of four single tensegrity modules. After updating and validating on the $2{\times}2$ grid, the finite element model is extended to a $8{\times}8$ grid (consisting of 64 units and measuring $8m{\times}8m$) whose behaviour is studied in detail for various load combinations expected to act on the structure. The results demonstrate that the proposed tensegrity grid structures are not only dismountable but also exhibit satisfactory behaviour from strength and serviceability point of view.