Random Load Simulation in Laboratory Fatigue Testing

1978 ◽  
Author(s):  
Jang Moo Lee ◽  
Kenneth G. Mcconnell
Keyword(s):  
Fatigue Testing ◽  
Random Load ◽  
Load Simulation

Finite Fatigue Life Distributions of SAE 1008 Subjected to Various Load-Time Histories

1980 ◽  
Vol 102 (1) ◽  
pp. 135-140 ◽  
Author(s):  
H. A. ElMaraghy ◽  
J. N. Siddall
Keyword(s):  
Fatigue Life ◽  
Fatigue Testing ◽  
Narrow Band ◽  
Fatigue Properties ◽  
Load History ◽  
Random Load ◽  
Bending Fatigue ◽  
Theoretical Predictions ◽  
Time Histories ◽  
Life Distributions

The probabilistic fatigue properties of SAE 1008 steel were determined experimentally. A flexural bending fatigue testing program was carried out consisting of: (a) constant strain amplitude, (b) blocks of Hi-Lo and Lo-Hi-Lo strain amplitudes, and (c) narrow band random load history. Fatigue life of 30-45 specimens in each program were recorded and used to construct distributions of fatigue life. A computer simulation technique was used to predict these distributions. Experimental results and theoretical predictions are both presented for comparison.

scholarly journals Development and evaluation of high-speed random load fatigue testing system.

1987 ◽  
Vol 36 (409) ◽  
pp. 1139-1144
Author(s):  
Masatoshi NIHEI ◽  
Satoshi NISHIJIMA ◽  
Takeshi KONNO ◽  
Tomoo SHIMONAKA ◽  
Yoshiaki HAYASHI ◽  
...  
Keyword(s):  
High Speed ◽  
Fatigue Testing ◽  
Testing System ◽  
Random Load

Bending fatigue testing of gear teeth under random loading

2001 ◽  
Vol 215 (7) ◽  
pp. 773-784 ◽  
Author(s):  
D Hanumanna ◽  
S Narayanan ◽  
S Krishnamurthy
Keyword(s):  
Fatigue Life ◽  
Power Transmission ◽  
Fatigue Testing ◽  
Cumulative Damage ◽  
Loading Conditions ◽  
Test Rig ◽  
Random Loading ◽  
Random Load ◽  
Bending Fatigue ◽  
Modes Of Failure

The gears in a gear box fitted in an armoured tracked vehicle for the purpose of power transmission and positioning of rotating heavy mass to the desired angle with high accuracy are subjected to fluctuating loads that are random in nature. One of the important modes of failure in cyclic loading conditions including random loads is fatigue failure. It is thus important from the design point of view to estimate the life of the gears under these conditions. The fatigue life of components subjected to sinusoidal loading can be estimated by using cumulative damage theories. Their extension to random load fatigue, though straightforward, may not be very accurate owing to inherent scatter exhibited by the fatigue phenomenon. It is therefore necessary experimentally to determine the fatigue life of randomly loaded components and establish the validity of the theoretical model. An electrohydraulic test rig has been designed and fabricated that is capable of generating different types of load pattern by adopting a suitable electronic circuit in the test rig. This paper presents the details of the test rig for random load generation, the test fixture for mounting the gear and the technique for testing the gear for bending fatigue life under random loading. A gear has been tested in the test rig under random loading conditions and also under constant amplitude conditions for bending fatigue, and the life of the gear has been obtained experimentally. Fatigue lives of the gear have also been estimated theoretically by employing linear cumulative damage theory using the peak count method.

Sun Load Analysis and Testing on Automotive Front Lighting Products

2020 ◽  
pp. 116-122
Author(s):  
Emre Öztürk ◽  
Mehmet Aktaş ◽  
Tunç Şenyüz
Keyword(s):  
Prolonged Exposure ◽  
Hot Spot ◽  
Load Test ◽  
Angle Of Incidence ◽  
The Sun ◽  
Solar Simulator ◽  
Automotive Lighting ◽  
Inclination Angles ◽  
Plastic Parts ◽  
Load Simulation

The purpose of this research is to reach good correlation between sun load simulation and solar focusing test for exterior automotive lighting products. Light coming from sun is highly collimated (parallel rays) and focusable from lenses with concave structure. Focusing incidence leads to a hot spot on lens surrounding plastic parts which may cause melting failures at high temperature zones. Sun load simulation is performing to eliminate risk of discoloration, deformation, out gassing, coating failures and fire with prolonged exposure from field. Irradiance values in W/m2 defined in simulation as heat source depending of an angle of incidence of the sun radiation. At first step, simulation is performing with 5 degree intervals to define the critical zones then intervals decreased to 2 degree to detect the critical azimuth and inclination angles. Critical azimuth and inclination angles is checking with ray trace analysis to check the bouncing of sun rays and possible solution to eliminate focuses with design solutions. After numerical analysis to release and validate the automotive lighting products regarding the sun load test, measurement with first parts is necessary. Measurement is performing for all critical angles which have been detected at simulation with thermal camera under ultra high-collimation solar simulator. Measured temperatures are settled according to environment conditions and correlation is checking with simulations.

Fatigue of Unidirectional Cord-Rubber Composites

1999 ◽  
Vol 27 (1) ◽  
pp. 48-57 ◽  
Author(s):  
Y. Liu ◽  
Z. Wan ◽  
Z. Tian ◽  
X. Du ◽  
J. Jiang ◽  
...  
Keyword(s):  
Damage Accumulation ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Constant Load ◽  
Testing System ◽  
Rubber Composites ◽  
Cycle Frequency ◽  
Periodic Loading ◽  
Fatigue Damage Accumulation ◽  
Rubber Composite

Abstract A fatigue testing system is established with which the real-time recording of stress, strain, temperature, and hysteresis loss of rubbers or cord-rubber composite specimens subjected to periodic loading or extension can be successfully carried out. Several problems are connected with the experimental study of the fatigue of rubber composites. In constant extension cycling, the specimen becomes relaxed because of the viscoelasticity of rubber composites, and the imposed tension-tension deformation becomes complex. In this method, the specimen is unlikely to fail unless the imposed extensions are very large. Constant load cycling can avoid the shortcomings of constant extension cycling. The specially designed clamps ensure that the specimen does not slip when the load retains a constant value. The Deformation and fatigue damage accumulation processes of rubber composites under periodic loading are also examined. Obviously, the effect of cycle frequency on the fatigue life of rubber composites can not be ignored because of the viscoelasticity of constituent materials. The increase of specimen surface temperature is relatively small in the case of 1 Hz, but the temperature can easily reach 100°C at the 8 Hz frequency. A method for evaluating the fatigue behavior of tires is proposed.

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