Closure to “Discussions of ‘Elastic Connecting-Rod Bearing With Piezoviscous Lubricant: Analysis of the Steady-State Characteristics’” (1978, ASME J. Lubr. Technol., 101, pp. 198–200)

1979 ◽  
Vol 101 (2) ◽  
pp. 200-200 ◽  
Author(s):  
B. Fantino ◽  
J. Frene ◽  
J. Du Parquet
Keyword(s):  
Steady State ◽  
Connecting Rod ◽  
Lubricant Analysis

Elastic Connecting-Rod Bearing With Piezoviscous Lubricant: Analysis of the Steady-State Characteristics

1979 ◽  
Vol 101 (2) ◽  
pp. 190-197 ◽  
Author(s):  
B. Fantino ◽  
J. Frene ◽  
J. Du Parquet
Keyword(s):  
Steady State ◽  
Film Thickness ◽  
Plane Elasticity ◽  
Operating Conditions ◽  
Maximum Pressure ◽  
Connecting Rod ◽  
Oil Film ◽  
Lubricant Analysis ◽  
Relative Eccentricity ◽  
Dimensional Equation

The effect of the deformation of an automotive connecting-rod on the oil film characteristics are studied. The simultaneous elastic deformation and pressure distribution are obtained by iterative methods in steady-state conditions under realistic speeds and loads (5500 rpm, 25,000 N). Plane elasticity relations are used in this study. The following parameters are investigated: —bearing characteristics: bearing thickness B and bearing clearance C, —operating conditions: journal speed N and applied load W, —lubricant: viscosity μ0 and piezoviscous coefficient α. As a result of the deformation, the maximum pressure and the attitude angle are decreased and the relative eccentricity is greatly increased. The minimum oil film thickness is slightly but systematically decreased. The piezoviscosity effect is noticeable only at high loads: it increases slightly the oil film thickness and the maximum pressure. An empirical dimensional equation for the minimum oil film thickness hm is derived numerically for the bearing considered. Thus: hm∼μ0NW0.5(1+0.06108α)B0.12C0.09

Wear Prediction in Connecting Rod Bearings During Running-In and Transient Speed Conditions

2010 ◽  
Author(s):  
Aurelian Fatu ◽  
Dominique Bonneau
Keyword(s):  
Steady State ◽  
Connecting Rod ◽  
Wear Coefficient ◽  
Wear Prediction ◽  
The Real ◽  
Time Required ◽  
Wear Condition

During running-in conditions, contact occurs between surface asperities, which induce wear and bearing shell profile adaptation. Firstly, the bearing wear evolution is investigated for different but constant engine rotational speeds. Secondly, the wear is investigated for transient speed conditions. By comparison with a realistic wear coefficient, the real engine time required to reach a steady-state wear condition is predicted.

Member Initial Curvature Effects on the Elastic Slider-Crank Mechanism Response

1982 ◽  
Vol 104 (1) ◽  
pp. 159-167 ◽  
Author(s):  
M. Badlani ◽  
A. Midha
Keyword(s):  
Steady State ◽  
Natural Frequency ◽  
Equations Of Motion ◽  
Excitation Frequency ◽  
Beam Theory ◽  
Connecting Rod ◽  
Initial Curvature ◽  
Curvature Effects ◽  
Transient Solutions ◽  
Crank Mechanism

Parametric vibration of initially curved columns loaded by axial-periodic loads has received considerable attention, concluding that regions of instability exist and that excitation frequencies less than the natural frequency of the principal resonance may occur. Recent publications have cautioned against the use of curved members in machines designed for precise operation, suggesting a detrimental coupling of the longitudinal and transverse deformations. In this work, the dynamic behavior of a slider-crank mechanism with an initially curved connecting rod is investigated. Governing equations of motion are developed using the Euler-Bernoulli beam theory. Both steady-state and transient solutions are determined, and compared with those obtained for the mechanism possessing a geometrically perfect (straight) connecting rod. A very small initial curvature is shown to cause a significantly greater steady-state response. The magnification in its transient response is shown to be even greater than that due to a straight connecting rod. Additionally, an excitation frequency less than the natural frequency is also shown to occur.

Theory and experiments on elastic connecting rod bearings under steady state conditions

1993 ◽  
pp. 49-54 ◽  
Author(s):  
J. Pierre Eugene ◽  
J. Frene ◽  
B. Fantino ◽  
G. Roussel ◽  
J. du Parquet
Keyword(s):  
Steady State ◽  
Connecting Rod ◽  
Theory And Experiments

Integration of Carbon Fiber Composite Materials Into Air-Cooled Reciprocating Piston Engines for UAV Applications

2012 ◽  
Author(s):  
Mark Trunzo ◽  
Joel Schubbe ◽  
Stephen M. Graham ◽  
Patrick Caton
Keyword(s):  
Steady State ◽  
Carbon Fiber ◽  
Fiber Composite ◽  
The United States ◽  
Extreme Condition ◽  
Small Displacement ◽  
Connecting Rod ◽  
Carbon Fiber Composite ◽  
Worst Case ◽  
Premature Failure

The United States Navy (USN) has shown an interest in the development of small displacement, reciprocating piston diesel engines for Unmanned Aerial Vehicles (UAVs). These engines avoid the logistic challenges of relying on gasoline-fueled UAVs, and have relatively low fuel consumption, but suffer from poor power-to-weight ratios. Reducing weight is of significant importance to UAVs to allow sufficient range and loitering times. Carbon fiber composites offer strength-to-weight benefits over the metal components currently used in piston engines. However, composite components have more restrictive operating temperatures. None of the known previous efforts aimed at integration of composites into engines has focused on air-cooled engines and on their potential benefits for UAVs. A small, single-cylinder air-cooled gasoline engine was chosen as a convenient test platform and surrogate for an air-cooled UAV engine. The crankcase and connecting rod from this engine were redesigned using a high fraction of carbon fiber in order to reduce weight. To develop the designs, steady-state temperature profiles were measured both internally and externally. The steady state temperatures for the crankcase ranged between 93°C and 124°C while the connecting rod ranged roughly between 120°C and 160°C. Carbon fiber composite test specimens were tested for strength at a comparable range of temperatures to demonstrate thermal viability. The tensile and compressive tests showed the carbon fiber to be comparable to all aluminum material properties, if not better. Stress was modeled on the stock engine at the worst-case operating condition and used to design the composite crankcase and connecting rod to ensure sufficient strength to survive at this extreme condition. The modeled stresses resulted in a factor of safety of 1.5 for the connecting rod and 3.8 for the crankcase, although internal adhesion of bearing surfaces to fiber was noted as a problem for the connecting rod in the initial prototype, and ultimately led to premature failure. These composite components were integrated and tested, for various lengths of time, on the engine and indicate a potential weight savings of approximately 80% for the crankcase and 26% for the connecting rod. The composite case failed after approximately 20 minutes (O(104) cycles) of operation at the best torque condition (worst-case in terms of mechanical stress) due to manufacturing deficiency at the corners and base; the connecting rod failed after approximately 2 minutes (O(103) cycles) of worst-case operation due to separation of the bearing surface from fiber. Both sets of failures point to simple remedies for follow-on work. The initial prototypes resulted in an overall weight savings of 8.1%. Using commercially available data for small propeller-driven aircraft, this weight savings could be expected to result in a similar relative improvement in aircraft range.

Effect of Internal Material Damping on the Dynamics of a Slider-Crank Mechanism

1983 ◽  
Vol 105 (3) ◽  
pp. 452-459 ◽  
Author(s):  
M. Badlani ◽  
A. Midha
Keyword(s):  
Steady State ◽  
Transverse Vibration ◽  
Equations Of Motion ◽  
Viscoelastic Model ◽  
Mathieu Equation ◽  
Perturbation Approach ◽  
Material Damping ◽  
Connecting Rod ◽  
The Stability ◽  
Crank Mechanism

A study of the effect of internal material damping on the dynamic response behavior of a slider-crank mechanism is presented in this paper. In developing the governing equations of motion, an assumption of a linear viscoelastic model for the connecting rod is made. A perturbation approach is utilized for reducing these coupled axial and transverse nonlinear equations to a nonhomogeneous damped Mathieu equation, describing the transverse vibration of the connecting rod. Both steady-state and transient solutions are determined and compared to those obtained from the use of an undamped connecting rod. It is demonstrated that the viscoelastic material damping can have significant influence, both favorable and adverse, in attempting to attenuate the steady-state and transient response of the connecting rod. The response is computed for several combinations of the excitation parameter and the frequency ratio. The stability of the transverse vibration of the connecting rod is also investigated in this paper.

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