• Composites Research
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• v.32 no.5
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• pp.243-248
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• 2019

As demand of light weight in the automotive industry has increased, the cowl cross member has been investigated using various methods to change the material. Conventionally, a cowl cross member has been made of steel and aluminum, but recently researchers tested multi-material such as aluminum and plastic. We studied a new model of the cowl cross member made of composite and non ferrous materials. For products with a high degree of freedom in design, generally, the method of topology optimization is advantageous and for the partial bracket part of the cowl cross member had a degree of freedom in the design, a topology optimization is appropriate. Considering the characteristics of the cowl cross members, we need research to minimize the weight while having the performance of noise, vibration and harshness(NVH). Taking the mounting status of the product into consideration, we used an assembly model to optimize the cowl cross member. But this method took too much time so we considered simple cowl cross member assemble conditions using the direct matrix input method(DMI) with the Craig-Bampton Nodal Method. This method is capable of considering the status of the assembly without assembling the model, which reduced the solving time and increased the accuracy comparison with a cowl cross member without DMI.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.2
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• pp.155-163
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• 2011

The flat type automotive cross members with high strength steel have advantages in light weight and fewer parts compared to the hump type cross members. But the complex part shape of the flat type cross member and the poor formability of high strength steel make it difficult to form the parts without forming defects, such as splits and wrinkles. The purpose of this study is to develop the flat type automotive cross member with high strength steel. For that purpose, drawing processes are evaluated using PAM-$STAMP^{TM}$ and proper draw die and blank designs are proposed. Using the proposed die and blank design, the flat type upper and lower cross member could be formed successfully without forming defects.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.717-718
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.409-410
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• 2009

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.3
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• pp.421-424
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• 2012

Carbon Fiber reinforced composite material can be designed for the optimized performances of structural member that have achieve appropriate mechanical properties with cross-sectional shape, fiber direction, stacking sequence and thickness. So there are needed extensive databases each optimal design of CFRP structural member by impact through the preparation of different shape, interface number, thickness and stacking angle. When pressure is applied to structural member, compression, bending and torsion is shown on the corresponding member. For the effective utilization of fiber reinforced composite material as main structural member, optimized design technology should be established to maximize mechanical properties for compression, bending and torsion. In this paper, CFRP prepreg sheet with different stacking angle is manufactured in CFRP and hybrid(Al+CFRP) with circular cross-section. Strength and stiffness is gotten respectively by flexure test. CFRP structure and hybrid structure can be compared with each other. The best design guideline can be analyzed by use of this study result.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.605-610
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• 2002

The purpose of this study is to develop an analytic model which can describe the behavior or concrete compressive member strengthened by CFS(Carbon Fiber Sheet) with various cross-sectional shapes such as circular. square, and octagonal and various laminate angles. The failure criterion of laminated CFS is based on Tsai-Wu failure criterion. The stress strain model of confined concrete compressive member is based on an equation proposed by Mander. The effective lateral confining pressure is considered and modified according to various cross-sectional shapes. Octagonal cross-section shows the best results in the aspect of ductility, while circular does in compressive strengthening effects. In addition, [0/0/0/0] laminate in which the direction of fiber is parallel to the direction of principal stress shows the superior strength and ductility than other laminates. The analytic results show that strength and ductility of the analytic model depend on the cross-sectional shapes as well as the laminate angles.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.297-300
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• 2009

The roll forming process is often used to manufacture long, thin-walled products such as a pipe. The final cross-section is a comparatively simple open-channel, a closed tube section or a complex profile with several bends. In recent years, that process is often applied to the bumper beam in the automotive industries. In this study, a optimal Center Floor Cross Member manufacturing technology, model deign and proper roll-pass sequences can be suggested by forming number of roll-pass and bending angle, and also effects of the process parameters on the final shape formed by roll forming defects were evaluated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.351-352
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• 2008

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.3
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• pp.127-133
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• 2018

To reduce fuel consumption, research on the weight reduction of vehicles is being actively carried out. Researchers have typically tried to replace metal materials with composites materials, but these materials did not satisfy the required strength and rigidity of a vehicle. Composites are usually not used because of their high cost. There are incomplete studies on lightweight trucks that transport cargo. Therefore, in this paper, we enhance the lightness and mechanical strength through design optimization of the deck frame for a lightweight truck. For that purpose, the side member and cross member, which are mounted on the lower part of the truck to assure the safety of the vehicle and support the luggage load, were targeted. The result of numerical analysis on the safety of the frame was obtained by changing the shape of each cross-section. To verify the numerical analysis, we compared it with the theoretical value of a cantilever beam. As a result, the suitability of the cross-sectional shapes of each frame was confirmed through numerical analysis.

• Asia pacific journal of information systems
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• v.33 no.2
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• pp.418-443
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• 2023

Many organizations facilitate a host of online knowledge sharing communities to assist internal knowledge sharing and operation. The permeable boundaries and voluntary structures of online communities allow individuals to span community boundaries and affect member resources and structures. Although much research has been done on members' knowledge contribution in online communities, relatively little is known about how a member's contribution to a community is shaped by the cross-level interactions of member's external boundary spanning and the community's environmental scanning or membership fluidity. Drawing from the theoretical lens of boundary spanning and the external view of online communities, we take a multi-level approach in the analysis of the activities of 1,992 members of 126 communities internal to a global company. We find that a member's external boundary spanning activity (e.g., external knowledge acquisition via reading posts) has a positive effect, though at a decreasing rate, on subsequent internal knowledge contribution (e.g., posting replies in the member's home community). This positive effect is stronger in communities that are more active in environmental scanning or have fluid membership and weaker in communities that are less active in environmental scanning or have stable membership.