• Computers and Concrete
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• v.19 no.5
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• pp.515-526
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• 2017

Recent trend is to use the lightweight concrete in the construction industry because it has several advantages over normal weight concrete. The Lightweight concrete can be produced from the industrial waste materials. In South East Asian region, researchers are very keen to use the waste materials such as oil palm shell (OPS) and palm oil clinker (POC) from the palm oil producing industries. Extensive research has been done on lightweight concrete using OPS or POC over the last three decades. In this paper the aggregate properties of OPS and POC are plotted in conjunction with mechanical and structural behavior of OPS concrete (OPSC) and POC concrete (POCC). Recent investigation on the use of crushed OPS shows that OPSC can be produced to medium and high strength concrete. The density of OPSC and POCC is around 20-25% lower than normal weight concrete. Generally, mechanical properties of OPSC and POCC are comparable with other types of lightweight aggregate concrete. It can be concluded from the previous study that OPSC and POCC have the noteworthy potential as a structural lightweight concrete.

• Journal of Electrochemical Science and Technology
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• v.14 no.2
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• pp.120-130
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• 2023

PEMFC has high potential for future development due to its high energy density, eco-friendliness, and high energy efficiency. When it becomes small, light and flexible, it can be competitive as an energy source for portable devices or flexible electronic devices. However, the use of hard and heavy materials for structural rigidity and uniform contact pressure transmission has become an obstacle to reducing the weight and flexibility of PEMFCs. This review intends to provide an example of the application of a new structure and material for lightweight and flexibility. As a lightweight PEMFC, a tubular design is presented and structural advantages through numerical modeling are explained. Manufacturing methods to realize the structural advantages and possibilities of tubular PEMFCs are discussed. In addition, the materials and manufacturing processes used to fabricate lightweight and flexible PEMFCs are described and factors affecting performance are analyzed. Strategies and structural improvements of light and flexible movements are discussed according to the component parts.

• International Journal of High-Rise Buildings
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• v.12 no.2
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• pp.145-152
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• 2023

Typical floor systems in contemporary tall buildings consist of reinforced concrete or composite metal deck over framing members and account for a majority of the structural weight of the building. The use of high-density materials, such as reinforced concrete and steel, increases the weight of floor systems, reducing the system's overall efficiency. With the introduction of high-performance materials, mainly mass timber products, and fiber-reinforced composites, in the construction industry, designers and engineers have multiple options to choose from when selecting structural materials. This paper discusses the application of mass timber and carbon fiber composites as structural materials in floor systems of tall buildings. The research focused on a comparative analysis of the structural system efficiency for five different design options for tall building floor systems. Finite Element Analysis (FEA) method was adopted to develop a simulation framework, and parametric structural models were simulated to evaluate the structural performance under specific loading conditions. Simulation results revealed the advantages of lightweight structural materials to improve system efficiency and reduce material consumption. The impact of mechanical properties of materials, loading conditions, and issues related to fire engineering and construction were briefly discussed, and future research topics were identified in conclusion.

• Journal of the Korean Society of Clothing and Textiles
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• v.17 no.3
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• pp.470-474
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• 1993

This study carried out to get some fundamental data for designing lightweight bedding. In This study, the wool blanket, polyester/cotton blended blanket and down quilt were manufactured with a varied materials, structural factors such as yam count, fabric density respectivelyarn. And also, the thermal insulation value of the bedding were measured by warmth retaining tester. In addition, this paper examines the influence of varying materials, structural factors and blanket layers on the thermal insulation effect of the bedding. The main results obtained from this study are as follow : 1. The design of lightweight blankets make an attempting with a varying materials and structural factors such as yam count, fabric densityarn. 2. Almost, the design of lightweight blankets for polyester/cotton blended blanket and down quilt make an attempting without reduction in thermal insulation values. 3. The 6 layers of blanket have less thermal insulation value than the 6 times of blanket for under a layer have. About 27~32% decrease is observed in thermal insulation value of blanket for under 6 layer. 4. The thermal insulation value and areal weight of blankets have a positive relation between the thermal insulation value(Y) and areal weight(X) is based on the following equation. wool blanket : Y = 1.0850X + 0.4188 (r = 0.9992) PIC blended blanket : Y = 0.8845X + 0.3034 (r = 0.9999)

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.1
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• pp.42-47
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• 2021

Recently, many structures using lightweight materials have been developed. This study was conducted by using Al6061-T6 and carbon fiber reinforced plastic (CFRP), two common lightweight materials. In addition, the failure characteristics of an interface bonded between a single material and a heterogeneous bonding material were analyzed. The specimens bonded with CFRP and Al6061-T6 were utilized by the combination of the heterogeneous bonding material. The specimens had a double cantilevered shape and the bonding between the materials was achieved by applying a structural adhesive. The experiments were conducted in opening mode: the lower part of the samples was fixed, while their upper part was subjected to a forced displacement of 3 mm/min by using a tensile tester. Under the tested amount of strength, energy release rate, and considering the specimens' fracture characteristics in opening mode, the specimen "CFRP-Al" presented the maximum stress, followed by "Al" and "CFRP". We can hence conclude that the inhomogeneous material "CFRP-Al" is useful for the construction of lightweight structures bonded with structural adhesive.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.6
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• pp.471-478
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• 2016

This paper describes a method to design a lightweight modular bridge for a railway infrastructure system. A lightweight design was achieved using the material selection method. Aluminum extrusions and honeycomb sandwich composites were selected as the best materials to reduce the weight of the upper structure of a conventional modular bridge made of carbon-steel material. The structural integrity of the lightweight modular bridge was evaluated under vertical and wind loads. The twisting and bending natural frequencies were also evaluated to investigate its dynamic characteristics. The results showed that the structural integrity and natural frequencies of the lightweight modular bridge, made of aluminum extrusion and sandwich composites, satisfied the design requirements. Moreover, it was found that the weight of the conventional modular bridge made of carbon steel could be reduced by a maximum of 47% using lightweight materials.

• Journal of the Korea Society for Simulation
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• v.29 no.2
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• pp.95-103
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• 2020

The structural connection design for lightweight structure application is presented in this paper. Modeling of the welding zone and the bolted connection are suggested. For reliability verification of the established models, nonlinear analysis is performed and comparisons are made with the experimental data showing good agreement. Through comparison study, suitable welding method for structure materials is investigated. Also, stability analysis is performed by fracture load simulation for different number and position of bolts. Finally, based on the structural connection models, the lightweight structure is modeled and structural analysis was performed. Stability analysis of structural connection for lightweight structure design, through combination of welding and bolting process, showed a 31.4% decrease in the maximum stress compared to the structure without the structural connections. Importance of structural connection design is highlighted for lightweight structure stability analysis.

• International Journal of Concrete Structures and Materials
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• v.5 no.2
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• pp.125-131
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• 2011

Five all-lightweight alkali-activated (AA) slag concrete mixes were tested according to the variation of water content to examine the significance and limitation on the development of cementless structural concrete using lightweight aggregates. The compressive strength development rate and shrinkage strain measured from the concrete specimens were compared with empirical models proposed by ACI 209 and EC 2 for portland cement normal weight concrete. Splitting tensile strength, and moduli of elasticity and rupture were recorded and compared with design equations specified in ACI 318-08 or EC 2, and a database compiled from the present study for ordinary portland cement (OPC) lightweight concrete, wherever possible. Test results showed that the slump loss of lightweight AA slag concrete decreased with the increase of water content. In addition, the compressive strength development and different mechanical properties of lightweight AA slag concrete were comparable with those of OPC lightweight concrete and conservative comparing with predictions obtained from code provisions. Therefore, it can be proposed that the lightweight AA slag concrete is practically applicable as an environmental-friendly structural concrete.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.6_2
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• pp.819-825
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• 2021

In the industry, the use of lightweight bearings is increasing to minimize motor power loss, and in particular, the application of next-generation systems such as robots and drones is increasing. Bearing manufacturers are producing lightweight bearings by changing the bearing material, but related researches is insufficient. In this paper, life test and structural analysis were performed for lightweight bearings, and shape parameters and scale parameters were derived based on the life test results. It was confirmed that the shape parameter was 2.52 and the scale parameter was 164 hours. As a result of calculating the dynamic load rating based on the B₁₀ life, it was confirmed that the dynamic load rating of the lightweight bearing was 7% compared to the formula suggested by ISO 281. The reason is that the material of the retainer, which is a major failure part, is a polyamide 66 series that reacts sensitively to heat, so It is judged to show a lot of difference from the ISO 281 calculation formula.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.6
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• pp.865-870
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• 2012

CFRP of the advanced composite materials as structure materials for vehicles has a widely application in lightweight structural materials of air planes, ships and automobiles because of high strength and stiffness compared with conventional materials. This study is to investigate the energy absorption characteristics and collapse mode of CFRP single and double hat shaped structural member under the axial static collapse test. The CFRP single and double hat shaped structural members stacked at different angles (${\pm}15^{\circ}$, ${\pm}45^{\circ}$, ${\pm}90^{\circ}$, $90^{\circ}/0^{\circ}$ and $0^{\circ}/90^{\circ}$ where the direction on $0^{\circ}$ coincides with the axis of the member). The axial static collapse tests were carried out for each member. Collapse mode and energy absorption characteristics of the each member were analyzed.