Novel Service Lifetime Estimation for an Oil-Damper Rubber Bush for a Railway Vehicle

2013 ◽  
Vol 739 ◽  
pp. 437-441
Author(s):  
Ho Kyung Kim
Keyword(s):  
Spring Constant ◽  
Railway Vehicle ◽  
Repeated Loading ◽  
Lifetime Estimation ◽  
Load Amplitude ◽  
Service Lifetime ◽  
Repeated Loads

A railroad bogie's components experience repeated loading during service. Especially, the oil-damper rubber bush becomes fatigue fractured on the plane between the rubber and the steel stem during service, and this results in inferior performance of the bogie. In this study, in order to offer a proper maintenance method for the bush, a novel service lifetime estimation for an oil-damper rubber bush operating under different repeated loads was proposed by normalizing the degrading rate of its spring constant. When 13,720 N, 11,760 N, and 9,800 N of repeated loads were applied to the rubber bush, final damage fraction was shown to be 63.7%, 50% and 40%, respectively. The normalizing lifetime (N/Nf) can be predicted as a function of damage fraction (D/Df), regardless of the load amplitude, as follows: N/Nf = 0.043 + 0.376(D/Df) + 0.489(D/Df)2.

Fatigue Life Prediction of Corroded Reinforced Concrete Beams under Repeated Loads

2011 ◽  
Vol 255-260 ◽  
pp. 504-508
Author(s):  
Li Song ◽  
Zhi Wu Yu
Keyword(s):  
Reinforced Concrete ◽  
Fatigue Life ◽  
Life Prediction ◽  
High Cycle Fatigue ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Repeated Loading ◽  
Test Results ◽  
Cycle Fatigue ◽  
Repeated Loads

The behavior of materials under repeated loading has been examined, but extended studies are more and more needed especially for damaged reinforced structures such as bridges, where high-cycle fatigue phenomena and corrosion can be significant. In the present paper, a theoretical model based on fatigue performance of materials and stress analysis for cross-section is proposed in order to analyze the fatigue damage of corroded reinforced concrete beams under repeated loads. Further, fatigue life is predicted by applying this method, and the method is evaluated by test results.

The Deformation of Partially Prestressed Elements Subjected to Repeated Static Loads

2018 ◽  
Vol 931 ◽  
pp. 328-333
Author(s):  
Salis Kh. Bayramukov ◽  
Zurijat N. Dolaeva
Keyword(s):  
Repeated Loading ◽  
Static Loads ◽  
Regulatory Documents ◽  
Operational Level ◽  
Elastoplastic Properties ◽  
Rectangular Profile ◽  
Repeated Load ◽  
Concrete Elements ◽  
Different Levels ◽  
Repeated Loads

The article deals with the change in the deflection of partially prestressed elements under repeated loading. Depending on the classes and the ratio of stressed and non-tensioned reinforcement, the effect of different levels of the repeated load application on the deformability index of the bent ferro-concrete elements is analyzed. Analysis of the experimental and calculated values ​​of deflections of rectangular profile beams after application of static repeated loads showed that regulatory documents underestimate the effect of the operational level repeated loads on the change in deflections at both average and high loading levels by more than 30%. Comparison of deflection values ​​was made immediately after application of repeated loads at the level of 60% from the destructive ones and after lifting the load to the level of 80%. To correct the values ​​of deflections within the limits of the calculated dependences of the norms, when subjected to the operational level repeated loads, it is proposed to take the value of the coefficient characterizing the elastoplastic properties of concrete equal to 0.3 for practical calculations. The results of the study increase the convergence of the experimental and theoretical values ​​of deflections in the range considered.

The Behaviour of Structures Under Repeated Loads

1947 ◽  
Vol 51 (441) ◽  
pp. 715-720 ◽  
Author(s):  
A. G. Pugsley
Keyword(s):  
Strain Gauge ◽  
Good Deal ◽  
The Other ◽  
Repeated Loading ◽  
Aircraft Structures ◽  
Repeated Loads

In recent years some types of aircraft have shown signs of structural trouble due to repeated loading and exploratory thought has therefore been given to the general problems arising. There are two main aspects to be considered: the nature and magnitude of the loads repeatedly occurring in flight and the behaviour and strength of aircraft structures under such loads. In this country a good deal of attention has already been given to the first side of the question, mainly by V-g recorder work, but also by some strain gauge investigations, but the other side of the matter—the resistance of aircraft structures to repeated loading— has so far received less attention. Direct experiments have not in this country gone much beyond exploratory work on a series of Typhoon tailplanes, described by Oaks and Townshend.

Behaviour of limited prestressed beams under repeated loads

1979 ◽  
Vol 6 (4) ◽  
pp. 544-556 ◽  
Author(s):  
G. G. Kulkarni ◽  
S. F. Ng
Keyword(s):  
Endurance Limit ◽  
Repeated Loading ◽  
Load Carrying Capacity ◽  
Tension Zone ◽  
Design Considerations ◽  
Load Carrying ◽  
Overall Stability ◽  
Crack Stability ◽  
Prestressed Beams ◽  
Repeated Loads

This investigation deals with the flexural and serviceability behaviour of limited prestressed beams under repeated loads and considers the concrete in the tension zone by relating the distribution of stresses in steel at and in between cracks. The consideration of crack stability and bond efficiency in achieving additional load-carrying capacity and the resulting economy are discussed from design considerations. The widening and deepening of cracks and their overall stability under severe conditions of repeated loading were studied by tests on limited prestressed beams having different distributions of steel and the results were used for comparison. The destruction of the bond between concrete and steel located between adjacent cracks under repeated loads was investigated in detail and the results were interpreted from endurance limit considerations. Theoretical analysis included computation of deflections and moments by considering the concrete located in the tension zone. Effects of repeated loads on load deflection hysteresis, crack pattern and stability, efficiency of bond between steel and concrete between adjacent cracks, contribution of concrete in tension towards increase in rigidity of beam, and endurance limit for working moments, stresses in steel and concrete expressed as percentage of ultimate are discussed in detail. It is seen that this method of accounting for the strength of concrete in the tension zone closely predicts the behaviour of beams.

Fatigue Life Prediction of Corroded RC Beams Strengthened with CFRP under Repeated Loads

2012 ◽  
Vol 166-169 ◽  
pp. 1534-1539
Author(s):  
Li Song ◽  
Zhi Wu Yu
Keyword(s):  
Fatigue Life ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymers ◽  
Repeated Loading ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Structural Deterioration ◽  
Externally Bonded ◽  
Term Performance ◽  
Repeated Loads

Structural deterioration is becoming a major problem when considering long-term performance of infrastructures. The actions of corrosive environment, repeated loading and concrete cracking lead to structural degradation, whereas externally bonded carbon fiber reinforced polymers (CFRP) may increases structural performance. In the present paper, a theoretical model based on fatigue performance of materials and stress analysis for cross-section is proposed in order to analyze the fatigue damage of corroded reinforced concrete beams strengthened with CFRP under repeated loads. Further, fatigue life is predicted by applying this method, and the method is evaluated by test results.

EELS Measurement of the Local Electronic Structure of Copper Atoms Segregated to Aluminum Grain Boundaries

1996 ◽  
Vol 54 ◽  
pp. 342-343
Author(s):  
S.J. Splinter ◽  
J. Bruley ◽  
P.E. Batson ◽  
D.A. Smith ◽  
R. Rosenberg
Keyword(s):  
Electronic Structure ◽  
Grain Boundaries ◽  
Boundary Segregation ◽  
Thin Layers ◽  
Nominal Composition ◽  
Spatially Resolved ◽  
Service Lifetime ◽  
Heat Treated ◽  
Probe Size ◽  
Local Electronic Structure

It has long been known that the addition of Cu to Al interconnects improves the resistance to electromigration failure. It is generally accepted that this improvement is the result of Cu segregation to Al grain boundaries. The exact mechanism by which segregated Cu increases service lifetime is not understood, although it has been suggested that the formation of thin layers of θ-CuA12 (or some metastable substoichiometric precursor, θ’ or θ”) at the boundaries may be necessary. This paper reports measurements of the local electronic structure of Cu atoms segregated to Al grain boundaries using spatially resolved EELS in a UHV STEM. It is shown that segregated Cu exists in a chemical environment similar to that of Cu atoms in bulk θ-phase precipitates.Films of 100 nm thickness and nominal composition Al-2.5wt%Cu were deposited by sputtering from alloy targets onto NaCl substrates. The samples were solution heat treated at 748K for 30 min and aged at 523K for 4 h to promote equilibrium grain boundary segregation. EELS measurements were made using a Gatan 666 PEELS spectrometer interfaced to a VG HB501 STEM operating at 100 keV. The probe size was estimated to be 1 nm FWHM. Grain boundaries with the narrowest projected width were chosen for analysis. EDX measurements of Cu segregation were made using a VG HB603 STEM.

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