• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.57-60
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• 2005

Composite-to-aluminum joins were tested to get failure loads and modes for three types of joins; adhesive bonding, bolt fastening, and adhesive-bolt hybrid joining. Film type adhesive FM73 and paste type adhesive Cytec EA9394S were used for aluminum and composite bonding to make a double-lap joint. A digital microscope camcorder was used to monitor the failure initiation and propagation. It was found that the hybrid joining is an effective method to strengthen the joint when the mechanical fastening is stronger than the bonding as in the case of using the paste type adhesive. On the contrary, when the strength of the bolted joint is lower than the strength of the bonded joint as in the joint with the film type adhesive, the bolt joining contribute little to the hybrid joint strength.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.727-730
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• 2001

In many structures a common method of construction is to make use of bolted or riveted joints. With this type of joint the load is transmitted through a pin from one section of the structure to another. Fatigue cracks often start from the edges of holes, due to local stress concentration. In order to predict the fatigue crack growth, the stress intensity factor K for hole-edge cracks should be available. In this paper the stress intensity factors are computed for cracks in bolt-joint region considering the contact condition.

• Steel and Composite Structures
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• v.12 no.2
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• pp.93-115
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• 2012

This paper presents a numerical investigation of the mechanical behaviour of extended end - plate steel connections including comparison with full size experiments. Contact and friction laws have been taken into account with nonlinear, three dimensional finite element analysis. Material and geometric nonlinearities have been implemented to the model, as well. Results are then compared with experimental tests conducted at the Jordan University of Science and Technology. According to the most significant observation of the analysis, a separation of the column flange from the extended end - plate occurs. Other important structural parameters of the connection, like the impact of some column stiffeners on the overall response, local buckling of the column and friction of the beam to column interface, have been examined as well.

• Smart Structures and Systems
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• v.7 no.5
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• pp.393-416
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• 2011

Hybrid acceleration-impedance sensor nodes on Imote2-platform are designed for damage monitoring in steel girder connections. Thus, the feasibility of the sensor nodes is examined about its performance for vibration-based global monitoring and impedance-based local monitoring in the structural systems. To achieve the objective, the following approaches are implemented. First, a damage monitoring scheme is described in parallel with global vibration-based methods and local impedance-based methods. Second, multi-scale sensor nodes that enable combined acceleration-impedance monitoring are described on the design of hardware components and embedded software to operate. Third, the performances of the multi-scale sensor nodes are experimentally evaluated from damage monitoring in a lab-scaled steel girder with bolted connection joints.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.4
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• pp.452-459
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• 2019

In order to design and manufacture structures such as a guided missile, assembly process with fastener is an essential method of fabrication. In this study, the dynamic characteristics of a cylindrical structure with bolted joints were studied using experimental methods. The change of the natural frequency of the structure with the change of the fastening method and the tightening torque were measured by the test and the finite element analysis was performed using the stiffness model of the fastening part according to the fastening method and compared with the test results.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.1
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• pp.111-118
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• 2022

The vehicle industry requires superior technology that can increase the efficiency of the battery of an electric vehicle. A coolant heater that can optimize the temperature of the battery is one of the most effective techniques for cold environments. However, the vibrations generated by this device can cause major complications, such as leakage and system errors. Therefore, the vibrations of the device must be suppressed to improve the stability. In this study, the fastening conditions of a coolant heater were analyzed using a computer simulation to investigate the natural frequencies and mode shapes which reflect the primary reasons for the largest vibrations under the given operating conditions. The results showed that six-bolted joints could considerably improve the stability of the fastening device

• Steel and Composite Structures
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• v.27 no.6
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• pp.727-745
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• 2018

The design criteria and the corresponding performance levels characterize the response of extended stiffened end-plate beam-to-column joints. In order to guarantee a ductile behavior, hierarchy criteria should be adopted to enforce the plastic deformations in the ductile components of the joint. However, the effectiveness of thesecriteria can be impaired if the actual resistance of the end-plate material largely differs from the design value due to the potential activation of brittle failure modes of the bolt rows (e.g., occurrence of failure mode 3 in the place of mode 1 per bolt row). Also the number and the position of bolt rows directly affect the joint response. The presence of a bolt row in the center of the connection does not improve the strength of the joint under both gravity, wind and seismic loading, but it can modify the damage pattern of ductile connections, reducing the gap opening between the end-plate and the column face. On the other hand, the presence of a central bolt row can influence the capacity of the joint to resist the catenary actions developing under a column loss scenario, thus improving the joint robustness. Aiming at investigating the influence of these features on both the cyclic behavior and the response under column loss, a wide range of finite element analyses (FEAs) were performed and the main results are described and discussed in this paper.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.5
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• pp.31-39
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• 2016

This paper is studied on the effect of the bolt joint stiffness on the Thrust Measurement Stand(TMS). TMS is a test stand for thrust performance of the propulsion system, which depends on two factors: The $1^{st}$ is the parallel degree between directions of the thrust vector and action lines of the corresponding measuring load cells for the vector, and the $2^{nd}$ is the orthogonality between action lines of the measuring load cells. Therefore, it is essential to maintain the original shape of the TMS under operating conditions. In this paper, it is examined how the geometric tolerance of the bolt joints and threads of the load cell trains affect the performance of the TMS. Also, some techniques to overcome related problems are proposed.

• Composites Research
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• v.36 no.4
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• pp.259-263
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• 2023

This study investigated the open hole tensile (OHT) properties of carbon fiber/epoxy composites and compared them to bolt joint tensile (BJT) properties. The net nominal modulus and strength (1376 MPa) were found to be higher than the gross nominal strength (1041 MPa), likely due to increasing hole size. The OHT and BJT specimens exhibited similar stiffness, as expected without bolt rotation causing secondary bending. OHT specimens experienced a sharp drop in stress indicating unstable crack propagation, delamination, and catastrophic failure. BJT specimens failed through shear out on the bolt side and bearing failure on the nut side, involving fiber kinking, matrix splitting, and delamination, resulting in lower strength compared to OHT specimens. The strength retention of carbon fiber/epoxy composites with open holes was 66%. Delamination initiation at the hole's edge caused a reduction in the stress concentration factor. Filling the hole with a bolt suppressed this relieving mechanism, leading to lower strength in BJT specimens compared to OHT specimens. Bolt joint efficiency was calculated as 15%. The reduction in strength in bolted joints was attributed to fiber-matrix splitting and delamination, aligning with Hart Smith's bolted joint efficiency diagram. These findings contribute to materials selection and structural reliability estimation for carbon fiber/epoxy composites. They highlight the behavior of open hole and bolt joint configurations under tensile loading, providing valuable insights for engineering applications.

• Journal of Korean Society of Steel Construction
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• v.20 no.6
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• pp.683-690
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• 2008

When steel fabricators erect structural members in field, temporary tightening of fastener should be useful. However, if bolt holes are not aligned by production error or natural condition, additional effort andpain should be provided to align bolt holes. It lead to longer period than times of construction (a primarily day of construction) and more cost than originally cost. This problem will be overcomed by oversize or slotted holes. Early, AISC and Eurocode have included provision for design process such oversize or slotted holes. But, domestic design method is not refered about oversize and slotted holes. Meanwhile, domestic design method and construction environment are variance with Europe and the United States of America. Therefore, a suitable design method for oversize and slotted holes in domestic real condition is needed. In this study, we evaluated behavior of the joints and decided the friction coefficient on oversize and slotted holes of friction joints with high strength bolts.