scholarly journals The effect of temperature on fatigue strength and cumulative fatigue damage of FRP composites

2010 ◽  
Vol 2 (1) ◽  
pp. 2011-2020 ◽  
Author(s):  
H. Mivehchi ◽  
A. Varvani-Farahani
Keyword(s):  
Fatigue Strength ◽  
Fatigue Damage ◽  
Effect Of Temperature ◽  
Frp Composites ◽  
Cumulative Fatigue Damage

scholarly journals The effect of temperature on fatigue strength and damage of FRP composite laminates

2021 ◽  
Author(s):  
Hossein Mivehchi
Keyword(s):  
Tensile Strength ◽  
Fatigue Strength ◽  
Ultimate Tensile Strength ◽  
Fatigue Damage ◽  
Composite Laminates ◽  
Damage Model ◽  
Effect Of Temperature ◽  
Temperature Dependent ◽  
Frp Composites ◽  
Frp Composite

The present study intends to investigate the effect of temperature on cumulative fatigue damage of laminated fibre-reinforced polymer (FRP) composites. The effect of temperature on fatigue damage is formulated based on a previously proposed residual stiffness fatigue damage model. The fatigue strength of FRP composite laminates is also formulated to have temperature dependent parameters. The research work is divided into three main parts; the first part reviews the fatigue damage mechanism is fibre-reinforced composites based on stiffness degradation. The recent residual stiffness of Varvani-Shirazi was used as the backbone structure of damage analysis in this thesis. This model is capable of damage assessment while the effects of maximum stress, stress ratio and fibre orientation of FRP composites were recognized. The Varvani-Shirazi damage model was further developed to assess fatigue damage of FRP composites at various temperatures (T). Inputs of the damage model are temperature dependent parameters including Young's modulus (E), ultimate tensile strength(ðult) and fatigue life (Nf). As the next part of the proposed analysis, the temperature dependency of each parameter is formulated, and the relations of E-T and ðult-T are substituted in the Varvani-Shirazi fatigue model. Finally, all terms and equations are evaluated with the experimental data available in the literature. Six sets fatigue data were used in this thesis to evaluate fatigue of FRP specimens. The predicted results were found to be in good agreement with the experimentally obtained data. The proposed fatigue damage model was found promising to predict the fatigue damage of unidirectional (UD) and women FRP composites at different temperatures. Temperature dependant parameters of Young's modulus, ultimate tensile strength, and S-N diagram were also found to be responsive when used of UD, cross-ply, and quasi-isotropic FRP laminates.

scholarly journals The effect of temperature on fatigue strength and damage of FRP composite laminates

2021 ◽  
Author(s):  
Hossein Mivehchi
Keyword(s):  
Tensile Strength ◽  
Fatigue Strength ◽  
Ultimate Tensile Strength ◽  
Fatigue Damage ◽  
Composite Laminates ◽  
Damage Model ◽  
Effect Of Temperature ◽  
Temperature Dependent ◽  
Frp Composites ◽  
Frp Composite

The present study intends to investigate the effect of temperature on cumulative fatigue damage of laminated fibre-reinforced polymer (FRP) composites. The effect of temperature on fatigue damage is formulated based on a previously proposed residual stiffness fatigue damage model. The fatigue strength of FRP composite laminates is also formulated to have temperature dependent parameters. The research work is divided into three main parts; the first part reviews the fatigue damage mechanism is fibre-reinforced composites based on stiffness degradation. The recent residual stiffness of Varvani-Shirazi was used as the backbone structure of damage analysis in this thesis. This model is capable of damage assessment while the effects of maximum stress, stress ratio and fibre orientation of FRP composites were recognized. The Varvani-Shirazi damage model was further developed to assess fatigue damage of FRP composites at various temperatures (T). Inputs of the damage model are temperature dependent parameters including Young's modulus (E), ultimate tensile strength(ðult) and fatigue life (Nf). As the next part of the proposed analysis, the temperature dependency of each parameter is formulated, and the relations of E-T and ðult-T are substituted in the Varvani-Shirazi fatigue model. Finally, all terms and equations are evaluated with the experimental data available in the literature. Six sets fatigue data were used in this thesis to evaluate fatigue of FRP specimens. The predicted results were found to be in good agreement with the experimentally obtained data. The proposed fatigue damage model was found promising to predict the fatigue damage of unidirectional (UD) and women FRP composites at different temperatures. Temperature dependant parameters of Young's modulus, ultimate tensile strength, and S-N diagram were also found to be responsive when used of UD, cross-ply, and quasi-isotropic FRP laminates.

The effect of temperature on fatigue damage of FRP composites

2010 ◽  
Vol 45 (14) ◽  
pp. 3757-3767 ◽  
Author(s):  
H. Mivehchi ◽  
A. Varvani-Farahani
Keyword(s):  
Fatigue Damage ◽  
Effect Of Temperature ◽  
Frp Composites

The Estimation of Fatigue Damage in Aircraft Wing Structures

1954 ◽  
Vol 58 (522) ◽  
pp. 396-402 ◽  
Author(s):  
A. H. Chilver
Keyword(s):  
Fatigue Strength ◽  
Fatigue Damage ◽  
Design Criteria ◽  
Characteristic Form ◽  
Structural Components ◽  
Aircraft Wing ◽  
Damage Rate ◽  
Wing Structures ◽  
Damage Law ◽  
Cumulative Fatigue Damage

SummaryA simple cumulative fatigue damage law is used to estimate the endurance of a number of typical structural components when subjected to the alternating wing loads encountered by an aircraft in flight. A method is developed to study the fatigue damage in terms of infinitesimally small intervals of alternating load and the corresponding fatigue strength. Recent gust data are used in conjunction with the complete fatigue strength diagrams of 13 simple components. The fatigue damage is studied for the ranges of altitude (i) up to 12,000 ft., and (ii) above 30,000 ft. In each case it is found that the damage rate curve, which gives the intensity of fatigue damage at any gust velocity, takes a characteristic form, with a well-defined range of gust velocities giving the greatest fatigue damage. This leads to a simplification of the whole problem, and it is found, finally, that the life of the structure is governed—in so far as the cumulative law is correct—almost entirely by that gust velocity, which, when applied alone to the structure, gives an endurance of about two million cycles. The results of the survey are compared with the design criteria suggested by Walker and the lives estimated by Williams.

scholarly journals Cumulative Fatigue damage of AA7075-T6 under Shot Peening and Ultrasonic Surface Treatments

2021 ◽  
Vol 14 (1) ◽  
pp. 1-10
Author(s):  
Marwa S. Mahammed ◽  
Hussain J. Alalkawi ◽  
Saad T. Faris
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Fatigue Damage ◽  
Shot Peening ◽  
Endurance Limit ◽  
Mechanical Design ◽  
Ultrasonic Impact Treatment ◽  
Sample Group ◽  
Cumulative Fatigue Damage ◽  
Fatigue Endurance

One of the important aspects of mechanical design is improving fatigue life.; In this work, the effect of Ultrasonic impact treatment (UIP) and shot peening (SP)on constant cumulative fatigue life and fatigue strength of AA7075-T6 were studied; The sample group was machined and primed, and some specimens were treated using ultrasonic impact therapy (UIT) with one line of peening. Fatigue experiments were conducted under constant and variable amplitude (R=-1) at ambient temperature to determine the fatigue life of the S-N curve and fatigue strength during treatment 3.46% and 8.57% at 107 cycles for (UIT) and (SP). Cumulative fatigue damage testing was carried out for two steps loading it is observed that the fatigue life for SP and UIP treated specimens was improved compared to the unpeeled results. The fatigue endurance limit was enhanced by 35% for UIT and 54% for SP. The fatigue life for both treatments was much improved compared to as-received metal. These results also show a strong tendency of increasing fatigue strength after application of (UIT) and (SP) with an increase in mechanical properties of the material used.

scholarly journals Fatigue Strength Analysis and Fatigue Damage Evaluation of Roller Chain

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 847 ◽  
Author(s):  
Ryoichi Saito ◽  
Nao-Aki Noda ◽  
Yoshikazu Sano ◽  
Jian Song ◽  
Takeru Minami ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Strength ◽  
Fatigue Damage ◽  
Fatigue Crack Initiation ◽  
Strength Analysis ◽  
The Finite Element Method ◽  
Roller Chain ◽  
Press Fitting ◽  
The Press ◽  
Static Tensile

This paper deals with the roller chain commonly used for transmission of mechanical power on many kinds of industrial machinery, including conveyors, cars, motorcycles, bicycles, and so forth. It consists of a series of four components called a pin, a bush, a plate, and a roller, which are driven by a sprocket. To clarify the fatigue damage, in this paper, the finite element method (FEM) is applied to those components under three different types of states, that is, the press-fitting state, the static tensile state, and the sprocket-engaging state. By comparing those states, the stress amplitude and the average stress of each component are calculated and plotted on the fatigue limit diagram. The effect of the plastic zone on the fatigue strength is also discussed. The results show that the fatigue crack initiation may start around the middle inner surface of the bush. As am example, the FEM results show that the fatigue crack of the inner plate may start from a certain point at the hole edge. The results agree with the actual fractured position in roller chains used in industry.

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