• International Journal of Automotive Technology
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• v.8 no.6
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• pp.723-730
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• 2007

The typical design of automotive driveshafts generally utilizes Constant Velocity(CV) joints as a solution to NVH. CV joints are an integral part of vehicles and significantly affect steering, suspension, and vehicle vibration comfort levels. Thus, CV joints have been favored over universal joints due to the constant velocity torque transfer and plunging capability. Although CV joints are common in vehicle applications, current research works on modeling CV joint friction and assumes constant empirical friction coefficient values. However, such models are long known to be inaccurate, especially under dynamic conditions, which is the case for CV joints. In this paper, an instrumented advanced CV joint friction apparatus was developed to measure the internal friction behavior of CV joints using actual tripod-type joint assemblies. The setup is capable of measuring key performance of friction under different realistic operating conditions of oscillatory speeds, torque and joint installation angles. The apparatus incorporates a custom-installed triaxial force sensor inside of the joint to measure the internal CV joint forces(including friction). Using the designed test setup, the intrinsic interfacial parameters of CV joints were investigated in order to understand their contact and friction mechanisms. The results provide a better understanding of CV joint friction characteristics in developing improved automotive driveshafts.

• Steel and Composite Structures
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• v.22 no.3
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• pp.613-625
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• 2016

The joints of the new prefabricated concrete assemble beam-column joints are put together by the hybrid joints of inserting steel under post-tensioned and non-prestressed force and both beams and columns adopt prefabricated components. The low cyclic loading test has been performed on seven test specimens of beam-column joints. Based on the experimental result, the rotation capacity of the joints is studied and the $M-{\theta}$ relation curve is obtained. According to Eurocode 3: Design of steel structures and based on the initial rotational stiffness, the joints are divided into three types; by equivalent bending-resistant stiffness to the precast beam, the equivalent modulus of elasticity $E_e$ is elicited with the superposition method; the beam length is figured out that satisfies the rigid joints and after meeting the requirements of application and safety, the new prefabricated concrete assemble beam-column joints can be regarded as the rigid joints; the design formula adopted by the standard of concrete joint classification is theoretically derived, thereby providing a theoretical basis for the new prefabricated concrete structure.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.624-629
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• 2001

Two types of bolted lap joints, one with a viscoelastic layer and the other without the viscoelastic layer were chosen to analyze the dynamic characteristics of the joints with the mechanical properties of the bolts of the joints being taken as computational variables. The finite element method was used along with the impact hammer technique to verify the FEM model. The results in the bolted lap joints reveal that the higher the Young's Modulus for the bolts are the higher the natural frequencies results for the joints. However, the natural frequency differences in the first and second mode are not substantial but become noticeable in the higher modes. Lower natural frequencies were obtained for the bolted lap joints with the viscoelastic layer when compared with those of the bolted lap joints without the viscoelastic layer. And the differences in the natural frequencies for the two types of joints are relatively small in the first and second mode whereas in the higher mode the differences become significant. The loss factors were observed to be significant especially in the second mode for the bolted lap joints with the viscoelastic layer.

• Steel and Composite Structures
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• v.2 no.2
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• pp.147-160
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• 2002

This paper summarises results of the research performed at the Department of Steel Structures and Structural Mechanics from the "Politehnica" University of Timisoara, Romania, in order to evaluate the performance of beam-to-column extended end plate connections for steel and composite joints. It comprises laboratory tests on steel and composite joints, and numerical modelling of joints, based on tests. Tested joints are double-sided, with structural elements realised of welded steel sections. The columns are of cruciform cross-section, while the beams are of I section. Both monotonic and cyclic loading, symmetrically and antisymmetrically, has been applied. On the basis of tested joints, a refined computer model has been calibrated using a special connection element of the computer code DRAIN 2DX. In this way, a static/dynamic structural analysis of framed structures with real characteristics of the beam to column joints is possible.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.897-902
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• 2000

In most of large panel pre-cast concrete system, the narrow joints have inefficiency to assemble several panels and structural problems due to their complicated process after construction. To improve, practically, structural performance and inefficiency to assemble, the behavior and strength of new wide joints method should be investigated experimentally. The result is that the shear force of wide joints is similar to that of loop joints, or more than. It seems that the use of wide joints is the possible methods in a construction field.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.774-777
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• 2002

There are various methods to join mechanical structures together. They typically include welding, mechanical joints by bolts and other processes depending on specific needs. Analyses of joints in the mechanical structures are essential in understanding the dynamic characteristics of the structures. In this research an impulse technique is applies to investigate the dynamic behavior of joints produced by bolts. The length overlap in the joints was varied as the number of the bolts in the joins was changed. Also, the torque applied to the bolts were adjusted. Resonance frequencies were determined for the joints to evaluate the relationship between the increase in the applied torque and the increase in the number of bolts used in the joints. The results have demonstrated that the resonance frequencies of the joints increase with the increasing torque.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.3
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• pp.495-501
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• 2001

In this paper, a new technique which models the joints characteristics through reduction of DOFs of structures with joints using component mode synthesis (CMS) method is proposed. Bolt joints are modeled by mass-spring systems. Also generalized mass and stiffness matrices for this models are introduced. Because bolt joints have influence on eigenvalues of structures, exact eigenvalues from modal test are used. The results show that the behaviors of structures with bolt joints depend to a large extent on the translational DOFs and not on rotational DOFs of mass and stiffness matrices of bolts. Furthermore it is confirmed that lumped mass-spring systems as models of bolt joints are effective models considering the facts that joint characteristics converged to constant values in some iterations and eignevalues from proposed method are in good agreement with ones from modal test.

• Advances in concrete construction
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• v.4 no.3
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• pp.161-172
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• 2016

An experimental investigation was carried out on the strength and behavior plain and fiber reinforced geopolymer concrete beam column joints and the results were compared with plain and steel fiber reinforced conventional concrete beam column joints. The volume fraction of fibers used was 0.5%. A total of six Geopolymer concrete joints and four conventional concrete joints were cast and tested under reversed cyclic loading to evaluate the performance of the joints. First crack load, ultimate load, energy absorption capacity, energy dissipation capacity stiffness degradation and moment-curvature relation were evaluated from the test results. The comparison of test results revealed that the strength and behavior of plain and fiber reinforced geopolymer concrete beam column joints are marginally better than corresponding conventional concrete beam column joints.

• Journal of the Korean Wood Science and Technology
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• v.23 no.4
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• pp.91-97
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• 1995

Cyclic tests were performed with dowel joints which are being widely used for furniture manufacturing in Korea. In this study, effects of various factors-such as species of joint members, diameter and length of dowels, and space between dowels-on stiffness, strength and damping ratio of joints were evaluated and concluded as follows: 1. Under cyclic loads, failure of dowel joints were caused by bending failure of dowels. 2. Dowel joints were evaluated to be stiff but general load carrying capacities were relatively low. 3. Joint moduli and damping ratios of dowel joints decreased as diameter and length of dowels, and space between dowels increased. 4. In dowel joints, properties of dowel itself have greater effects on stiffness and strength of joints than properties of joint members.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.2
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• pp.157-162
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• 2010

This paper describes the thermal fatigue life prediction models for 95.5Sn-4.0Ag-0.5Cu solder joints of Flip chip package considering Under Bump Metallurgy(UBM). A 3D Finite element slice model was used to simulate the viscoplastic behavior of the solder. For two types of solder bump pitches, simulations were analyzed and the effects of underfill packages were studied. Consequently, it was found out that solder joints with underfill had much better fatigue life than solder joints without underfill, and solder joints with $300{\mu}m$ bump pitch had a longer thermal fatigue life than solder joints with $150{\mu}m$ bump pitch. Through the simulations, flip chip with lead-free solder joints should be designed with underfill and a longer bump pitch.