Development of Random Fatigue Data for Adhesively Bonded and Weldbonded Structures Subjected to Dynamic Excitation

1978 ◽  
Vol 100 (1) ◽  
pp. 70-76 ◽  
Author(s):  
K. R. Wentz ◽  
H. F. Wolfe
Keyword(s):  
Fatigue Life ◽  
Adhesive Bond ◽  
Experimental Investigations ◽  
Metal Fatigue ◽  
Adhesively Bonded ◽  
Dynamic Excitation ◽  
Modes Of Failure ◽  
Sonic Fatigue ◽  
Random Fatigue ◽  
Adhesively Bonded Structures

Prediction methods are being developed to determine the sonic fatigue life of various weldbonded and adhesively bonded aircraft structures when exposed to high intensity acoustic excitation. This paper describes the results of the experimental investigations performed by the AF Flight Dynamics Laboratory to obtain the factors that affect the random fatigue life of typical aircraft structural joint configurations. The structures tested included full-scale components, simple beam sections, and acoustic panel configurations. A variety of aluminum skin thicknesses, stiffener configurations, and bond systems have been tested under dynamic excitation. The bond systems tested begin with the weldbond systems developed in the early 1970s up to the present bond systems. Random flexural fatigue curves for two modes of failure have been developed: adhesive bond system failure and metal fatigue failure. These curves are part of the design criteria needed to predict the sonic fatigue life of weldbonded and adhesively bonded structures.

Evaluation of Fatigue Life of Automotive Bevel Gear

2006 ◽  
Vol 324-325 ◽  
pp. 839-842
Author(s):  
Jae Hoon Kim ◽  
Duck Hoi Kim ◽  
Young Shin Lee ◽  
Gi Gwang Kim
Keyword(s):  
Fatigue Life ◽  
Fatigue Test ◽  
Fatigue Loading ◽  
Analytical Investigation ◽  
Bevel Gear ◽  
Cold Forging ◽  
Experimental Investigations ◽  
Bending Fatigue ◽  
Bending Fatigue Test ◽  
Random Fatigue

This paper presented the results for experimental investigations and numerical analysis performed with the aim of studying on fatigue life of hobbed and cold forged bevel gears used in automobiles. To evaluate the bending fatigue strength improvement by cold forging process, fatigue test and analysis were performed. For the monotonic fatigue loading, bending fatigue test and analysis were carried out. To simulate the real driving condition, random fatigue loading was defined here, and the random fatigue analysis was also performed. It was concluded that fatigue life and crack initiation sites of automotive bevel gear were well agreed with the test results. Fatigue lives for hobbed and cold forged bevel gear from experimental and analytical investigation were also presented and compared.

scholarly journals Stress Intensity Factor Assessment for the Reinforcement of Cracked Steel Plates Using Prestressed or Non-Prestressed Adhesively Bonded CFRP

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1625
Author(s):  
Emilie Lepretre ◽  
Sylvain Chataigner ◽  
Lamine Dieng ◽  
Laurent Gaillet
Keyword(s):  
Stress Intensity Factor ◽  
Finite Element ◽  
Fatigue Life ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Tip ◽  
Steel Plates ◽  
Experimental Investigations ◽  
Adhesively Bonded ◽  
Element Analysis

The use of adhesively bonded carbon fiber reinforced polymer (CFRP) materials to reinforce cracked steel elements has gained widespread acceptance in order to extend the lifespan of metallic structures. This allows an important reduction of the stress intensity factor (SIF) at the crack tip and thus a significant increase of the fatigue life. This paper deals with the assessment of the SIF for repaired cracked steel plates, using semi-empirical analysis and finite element analysis. Metallic plates with only one crack originating from a center hole were investigated. Virtual crack closure technique (VCCT) was used to define and evaluate the stress intensity factor at crack tip. The obtained modeling results are compared with experimental investigations led by the authors for different reinforcement configurations including symmetrical and non-symmetrical reinforcement, normal modulus and ultra-high-modulus CFRP plates, and pre-stressed CFRP plates. Results show that finite element model (FEM) analysis can obviously simulate the fatigue performance of the CFRP bonded steel plates with different reinforcement configurations. Moreover, a parametric analysis of the influence of the pre-stressing level was also conducted. The results show that an increase of the pre-stressing level results in an increase of the fatigue life of the element.

Comparative study of adhesive fatigue in aeronautical bonded joints: A numerical approach in the frequency domain

2021 ◽  
pp. 146442072110500
Author(s):  
Denys Marques ◽  
Marcelo L Ribeiro ◽  
Volnei Tita
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Adhesive Layer ◽  
Numerical Approach ◽  
Bonded Joints ◽  
Cohesive Failure ◽  
Adhesively Bonded ◽  
Random Loads ◽  
Bonded Joint ◽  
Adhesively Bonded Structures

The use of adhesively bonded structures has increased over the years, together with the development of composite materials. This work investigates a procedure for fatigue life prediction of an aeronautical bonded joint under random loads, in particular, the cohesive failure of the adhesive layer in a skin-to-stiffener bonded joint. The use of two different adhesives is investigated, and Dirlik’s method is employed to predict the stress response in the adhesive layer, from which the fatigue life is obtained. The effect of damping is also investigated, and it is shown that increases in damping result in higher fatigue life estimations.

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