Efficiency of the method of spectral vibrodiagnostics for fatigue damage of structural elements. Part 4. Analysis of distortion of harmonicity of vibration cycle of beams with closing transverse cracks

2000 ◽  
Vol 32 (1) ◽  
pp. 1-6 ◽  
Author(s):  
V. V. Matveev ◽  
A. P. Bovsunovskii
Keyword(s):  
Fatigue Damage ◽  
Structural Elements ◽  
Transverse Cracks

Fatigue Damage Accumulation Prediction for Combined Sine and Random Stresses

1988 ◽  
Vol 31 (3) ◽  
pp. 53-63
Author(s):  
Ronald Lambert
Keyword(s):  
Fatigue Life ◽  
Closed Form ◽  
Fatigue Damage ◽  
Damage Accumulation ◽  
Structural Elements ◽  
Numerical Examples ◽  
Stress Situation ◽  
Fatigue Damage Accumulation ◽  
Special Cases ◽  
Parameters Of Interest

Simple closed-form expressions have been derived to predict fatigue life, damage accumulation, and other fatigue parameters of interest for structural elements with combined sinusoidal (sine) and narrowband Gaussian random stresses. These equations are expressed in common engineering terms. The sine and random only stress situations are special cases of the more general combined sine/random stress situation. They also have application for establishing vibration workmanship screens. Numerical examples are also included.

Use of fatigue-damage transducers to evaluate the loading of structural elements

1984 ◽  
Vol 16 (12) ◽  
pp. 1663-1667
Author(s):  
V. T. Troshchenko ◽  
V. A. Kuz'menko ◽  
B. Z. Kruk ◽  
V. I. Boiko
Keyword(s):  
Fatigue Damage ◽  
Structural Elements

scholarly journals Study of running engines inertial and gyroscopic properties influence on the dynamic system engine – pylon – wing structural capabilities

2020 ◽  
Vol 23 (3) ◽  
pp. 63-72
Author(s):  
V. V. Ovchinnikov ◽  
Yu. V. Petrov
Keyword(s):  
Dynamic System ◽  
Fatigue Damage ◽  
Dynamic Properties ◽  
Elastic Beam ◽  
Aircraft Engine ◽  
Basic Structure ◽  
Elastic Vibration ◽  
Rigid Bodies ◽  
Practical Implementation ◽  
Structural Elements

A modern large-sized aircraft dynamic properties analysis, determined by the specificity of its layout scheme, demonstrates that the engines on under the wing elastic pylons lightly damped oscillations cause a number of undesirable phenomena, including intense accumulation of fatigue damage of the pylon-to-the-wing attachment, in fact in the area of engine installation in the pylon and the wing. The results of theoretical and experimental research show that with some engine attachment to the pylon structural modification it becomes possible to use the engines inertial and gyroscopic properties to absorb these oscillations. In this case, the motor tones damping coefficients increase by an order of magnitude or even more, so the gyroscopic coupling of elastic vibration tones is realized. With the rational choice of the additional parameters of elastic and dissipative bonds in the engine attachments it is possible to affect the aircraft wing and engines aero elastic vibrations effectively, which has a significant effect on the aircraft elements structural capabilities. A mathematical model of aero elasticity (MMAE) with respect to the kinetic moment of the engine rotors and specially designed units for attaching the engines to the pylons was developed in order to study the influence and the selection of rational elastic-dissipative parameters of the pylons-under-the-wing aircraft engine mounts. The method of predetermined basic forms is used for the aircraft with running engines on the pylons MMAE synthesis. The given forms are considered as the aircraft basic structure forms natural vibrations in the void. This work treats the engine nacelle and the rotor as absolutely rigid bodies, the elasticity of the rotor to the nacelle attachment is neglected. The pylon is modeled by an elastic beam, and the elastic and dissipative properties of the pylon-to-the-wing and the engine-to-the-pylon attachments are correspondingly by elastic-dissipative bonds. Schematic diagrams of the engine to the pylon attachments are proposed. The results of the study devoted to the influence of the proposed attachment points modifications on the load and integral strength characteristics of the main structural elements of the engine – pylon – wing dynamic system on the example of an An-124 aircraft are presented. The practical implementation of the proposed solutions aimed to reduce the level of fatigue damage to structural elements of the aircraft feasibility is proved.

Degradation of the surface layers of superalloys and thermal-fatigue damage to the structural elements of gas-turbine engines

2008 ◽  
Vol 40 (5) ◽  
pp. 552-559 ◽  
Author(s):  
L. V. Kravchuk ◽  
R. I. Kuriat ◽  
K. P. Buiskikh ◽  
S. G. Kiselevskaya
Keyword(s):  
Gas Turbine ◽  
Fatigue Damage ◽  
Thermal Fatigue ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Structural Elements ◽  
Surface Layers

Fatigue Damage Prediction for Combined Random and Static Mean Stresses

1993 ◽  
Vol 36 (3) ◽  
pp. 25-32
Author(s):  
Ronald Lambert
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Narrow Band ◽  
Stress Rupture ◽  
Structural Elements ◽  
Damage Prediction ◽  
Static Tensile ◽  
Analytical Expressions ◽  
Static Tensile Stress ◽  
Mean Stresses

Closed form analytical expressions have been derived and are proposed for use to predict accumulated fatigue damage and fatigue life of structural elements subjected to a combination of fully reversed narrow-band Gaussian random and static mean stresses. Such mean stresses can significantly alter fatigue life. The proposed method of combining random alternating and mean stresses shows excellent agreement with published experimental data for a steel alloy. Reasonable agreement is maintained, surprisingly, even for static tensile stress values up to near the material's yield stress where the failure mode shifts from that of typical brittle fatigue to that of stress rupture (i.c.,creep). Numerical examples are provided to illustratc the application.

scholarly journals Probabilistic Estimation of Fatigue Damage in Structural Elements

2016 ◽  
Author(s):  
А.С. Гусев ◽  
◽  
К.Б. Даниленко ◽  
С.А. Стародубцева ◽  
◽  
...  
Keyword(s):  
Fatigue Damage ◽  
Structural Elements ◽  
Probabilistic Estimation

Integrity of aircraft structural elements with multi-site fatigue damage

1995 ◽  
Vol 51 (3) ◽  
pp. 361-380 ◽  
Author(s):  
Jai H. Park ◽  
Ripudaman Singh ◽  
Chang R. Pyo ◽  
Satya N. Atluri
Keyword(s):  
Fatigue Damage ◽  
Structural Elements
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