• Journal of the Korean Society for Heat Treatment
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• v.19 no.3
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• pp.163-169
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• 2006

Fretting is a kind of surface degradation mechanism observed in mechanical components and structures. The fretting damage decreases into 50-70% of the plain fatigue strength. The connecting rod for automobile has been used in special environments and various loading conditions. Failure of connecting rod in automotive engine may cause catastrophic situation. In this study, we investigated the fatigue characteristic of connecting rod material for an automobile. Fatigue life is defined as the number of cyclic stress to failure by regular cyclic stress. Fatigue life of C70S6 specimen was obtained from 134,000 to 147,000 cycles. Fatigue limit showed 432MPa by normal fatigue test. The other hands, it was 96MPa in the case of fretting fatigue test. It was extremely lower than that of a normal fatigue test. From observation of fracture surface, it was confirmed that the fatigue crack was initiated at the boundary of a specimen and bridge pad.

• Journal of Biosystems Engineering
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• v.37 no.6
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• pp.359-364
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• 2012

Purpose: This study was conducted to analyze the vibration absorption effect for the agricultural product transportation-trailer equipped with vibration absorbable connecting hitch, leaf spring suspension, and shock absorber simultaneously (HLS), comparing with the trailer equipped with vibration absorbable connecting hitch only(H), trailer equipped with connecting hitch and leaf spring suspension (HL), and existing trailer with no vibration absorption device (E). Methods: Vertical accelerations were measured at driver seat and front, middle, rear parts of trailer bottom with no load for 4 types of transportation-trailer, and analyzed using FFT analyzer. Results: The magnitude of average vibration accelerations occurred up to 20 Hz, at this low frequencies the severe damage for agricultural products could be represented, was lower (maximum 6 times) for HLS trailer compared with H trailer. And vibration absorption effect for HLS trailer was also higher up to 40-80 Hz and 80-100 Hz, but the difference was less. At driver seat, the vibration absorption effect was high severely for HL and HLS trailer, and the magnitude of vibration acceleration was showed less difference in comparing at trailer bottom. Conclusions: From the test results, it could be recommended that the agricultural products transportation trailer should be equipped with vibration absorption device of HLS.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.794-798
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• 1995

We performed analysis for crank shaft and connecting rod in driving device of Cold Heading Machine. The results of this study is following ; 1. The nominal pressure is happened at 8mm under bottom dead center. And then the theoretical angel of crank (.theta.) and connecting rod (.phi.) are .theta. = 25 .deg. 1' and .phi.= 6 .deg. 1' but the analysis angel are .theta. = 25 .deg. and .phi.= 7 .deg. 2. The load is loaded at theta. = 51 .deg. in crank angle. 3. The maximum stress of connecting rod is about290MPa. It is exited inner stress range in consideration of safety factor.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.441-444
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• 1998

This paper is concerned with researching latch-up immune CMOS structure was performed. By the simulation results, the connecting layer had more effect than the buried layer to latch-up immune. When the connecting layer was the dose 1*10$^{14}$ /cm$^{2}$ and the energy 500KeV, the trigger current was more 0.6mA/.mu.m and the trigger voltage was 6V. The more the connecting layer dose was lower, the more the latch-up immune characteristics was butter.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.393-398
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• 2001

This paper aims to work process of connecting rod die using CAD/CAM/CNC systems. CAD/CAM/CNC systems are consist of CAD(MDT4.0), CAM(Z-MASTER) software and CNC milling machine. CAM software is purpose to G-code generation for CNC programming. Then CAM software and CNC milling machine are connect to RS-232-C cable for data network.

• Tribology and Lubricants
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• v.14 no.3
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• pp.39-45
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• 1998

Reynolds equation, which describes behavior of fluid film in journal bearings, basically satisfies mass conservation. But, boundary conditions usually used with this equation, e.g. half Sommerfeld or Reynolds boundary conditions, cannot fulfill this natural law of conservation. In the case of connecting rod bearing, where applied load is dynamic and its magnitude is relatively large, such unrealistic boundary conditions have serious influence on calculation results, especially on lubricant flow rate or power disspation which are important parameters in thermal analysis. In this paper, mass-conserving boundary condition was applied in the finite element analysis of connecting rod bearings. Lubricant flow rate and power dissipation rate were calculated together with journal center locus, minimum film thickness and maxmium film pressure. These computation results were compared with those of the case of Reynolds boundary condition. Balance between inlet and outlet flow rate was well achieved in the case of mass-conserving boundary condition.

• International Journal of Automotive Technology
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• v.8 no.3
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• pp.319-325
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• 2007

Preload of critical engine bolts affects the performance and durability of engines. In modern engines that pursue higher power outputs and which are of lighter weight, it becomes more difficult to select an optimal target preload in consideration of various factors such as the role and structural characteristics of joint members, joint load, and fatigue durability of bolts and joint members. A procedure to select the bolt preload using computer-aided engineering technology, especially the finite element method, has been developed. The procedure is illustrated with connecting-rod bolts for which an appropriate preload is known. The selection criteria of target preload and the finite element modeling technique for connecting-rod bolts are also explained.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.14-20
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• 2008

Fatigue fracture of engine connecting-rod bolts is encountered frequently during the developement of high-speed engines. Only the engine dyno test is a currently reliable fatigue durability assessment method. It is because the available rig tests cannot mimic the engine running condition completely, and because the finite element analysis cannot provide realistic stresses near the bolt thread that is modeled as a cylinder. This paper introduces a methodology to assess the fatigue durability of the connecting-rod bolts using the finite element analysis. The methods to contruct the bolt model, to extract the critical bolt stresses for the fatigue analysis, and to obtain the bolt fatigue endurance limit experimentally are discussed. Reliability of the method is verified indirectly.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1997.04a
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• pp.183-189
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• 1997

This paper presents the motion of dynamically loaded journal in the connecting rod bearing of reciprocating internal combustion engine. Journal motions in engine bearings have been composed of two components, which was rotational and translational motion. Early study of journal locus in engine bearing had been performed on each motion. This paper has been considered two motions simultaneously. Reynolds equation including the squeeze effect has been analyzed using the ADI method, and real engine bearing and crankshaft system has been considered to calculate the cyclic external force. The equations of journal motion have been derived and then the numerical integration of these equations performed by 4th order Runge-Kutta method. This paper gives various journal orbits in connecting rod bearing depending on cyclic external forces, rotating speeds, and bearing parameters.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.621-625
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• 1997

Recently, wash plate type hydraulic axial piston motors are being in extensively used in the world, because of simple design, lightweight, effective cost. But the structural problem of swash plate type hydraulic axial piston motor is the limited angle of swash plate and lateral force having a undesirable effect in piston. To solve these problems. a connecting rod mechanism. which is commonly used in hent axis type motors, is considered to be applied the swash plate cype motor. In this paper, kinematic analysis is done on the connecting rod mechanism. A series of formula are derived and numerical calculations are done for a set of motor parameters.