Evolution of a Martensite Packet under Multicycle Fatigue Loading

From the perspective of damage mechanics, the damage parameters were introduced as the characterizing quantity of the decrease in the mechanical properties of powder superalloy material FGH96 under fatigue loading. By deriving a damage evolution equation, a fatigue life prediction model of powder superalloy containing inclusions was constructed based on damage mechanics. The specimens containing elliptical subsurface inclusions and semielliptical surface inclusions were considered. The CONTA172 and TARGE169 elements of finite element software (ANSYS) were used to simulate the interfacial debonding between the inclusions and matrix, and the interface crack initiation life was calculated. Through finite element modeling, the stress field evolution during the interface debonding was traced by simulation. Finally, the effect of the position and shape size of inclusions on interface debonding was explored.

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Finite-element simulation of multi-axial fatigue loading in metals based on a novel experimentally-validated microplastic hysteresis-tracking method

Finite Elements in Analysis and Design ◽

10.1016/j.finel.2020.103481 ◽

2021 ◽

Vol 187 ◽

pp. 103481

Author(s):

F. Mozafari ◽

P. Thamburaja ◽

N. Moslemi ◽

A. Srinivasa

Keyword(s):

Finite Element ◽

Finite Element Simulation ◽

Fatigue Loading ◽

Tracking Method ◽

Element Simulation ◽

Axial Fatigue

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Experimental study on magnesium wire–polylactic acid biodegradable composite implants under in vitro material degradation and fatigue loading conditions

Composite Structures ◽

10.1016/j.compstruct.2021.114267 ◽

2021 ◽

pp. 114267

Author(s):

Syed Hasan Askari Rizvi ◽

Jiale-Che ◽

Ali Mehboob ◽

Usama Zaheer ◽

Seung-Hwan Chang

Keyword(s):

Experimental Study ◽

Polylactic Acid ◽

Fatigue Loading ◽

Loading Conditions ◽

Material Degradation ◽

Biodegradable Composite

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Theoretical and Experimental Fatigue Strength Calculations of Lips Compensating Circumferential Backlash in Gear Pumps

Energies ◽

10.3390/en14010251 ◽

2021 ◽

Vol 14 (1) ◽

pp. 251

Author(s):

Piotr Osiński ◽

Grzegorz Chruścielski ◽

Leszek Korusiewicz

Keyword(s):

Maximum Stress ◽

Theoretical Calculations ◽

Fatigue Loading ◽

Minimum Thickness ◽

Bending Tests ◽

External Gear Pumps ◽

Gear Pumps ◽

In Series ◽

Number Of Cycles ◽

Technical Solutions

This article presents theoretical and experimental calculations of the minimum thickness of a compensation lip used in external gear pumps. Pumps of this type are innovative technical solutions in which circumferential backlash (clearance) compensation is used to improve their volumetric and overall efficiency. However, constructing a prototype of such a pump requires long-lasting research, and the compensation lip is its key object, due to the fact that it is an element influenced by a notch and that it operates in unfavorable conditions of strong fatigue stresses. The theoretical calculations presented in this article are based on identifying maximum stress values in a fatigue cycle and on implementing the stress failure condition and the conditions related to the required value of the fatigue safety factor. The experimental research focuses on static bending tests of the lips as well as on the fatigue loading of the lips in series of tests at increasing stress values until lip failure due to fatigue. The tests allowed the minimum lip thickness to be found for the assumed number of fatigue cycles, which is 2.5 times the number of cycles used in wear margin tests.

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Effects of overload mode-mixity on fatigue damage behavior and governing micromechanisms in AA7075 under biaxial fatigue loading

International Journal of Fatigue ◽

10.1016/j.ijfatigue.2021.106141 ◽

2021 ◽

pp. 106141

Author(s):

Abhay K. Singh ◽

Siddhant Datta ◽

Aditi Chattopadhyay ◽

Nam Phan

Keyword(s):

Fatigue Damage ◽

Fatigue Loading ◽

Mode Mixity ◽

Damage Behavior ◽

Biaxial Fatigue

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Mode I Crack Propagation Experimental Analysis of Adhesive Bonded Joints Comprising Glass Fibre Composite Material under Impact and Constant Amplitude Fatigue Loading

Materials ◽

10.3390/ma14164380 ◽

2021 ◽

Vol 14 (16) ◽

pp. 4380

Author(s):

Alirio Andres Bautista Villamil ◽

Juan Pablo Casas Rodriguez ◽

Alicia Porras Holguin ◽

Maribel Silva Barrera

Keyword(s):

Crack Propagation ◽

Structural Integrity ◽

Crack Propagation Rate ◽

Fatigue Loading ◽

Propagation Rate ◽

Operating Conditions ◽

Impact Testing ◽

Mode I ◽

Mode I Crack ◽

Constant Amplitude

The T-90 Calima is a low-wing monoplane aircraft. Its structure is mainly composed of different components of composite materials, which are mainly bonded by using adhesive joints of different thicknesses. The T-90 Calima is a trainer aircraft; thus, adverse operating conditions such as hard landings, which cause impact loads, may affect the structural integrity of aircrafts. As a result, in this study, the mode I crack propagation rate of a typical adhesive joint of the aircraft is estimated under impact and constant amplitude fatigue loading. To this end, effects of adhesive thickness on the mechanical performance of the joint under quasistatic loading conditions, impact and constant amplitude fatigue in double cantilever beam (DCB) specimens are experimentally investigated. Cyclic impact is induced using a drop-weight impact testing machine to obtain the crack propagation rate (da/dN) as a function of the maximum strain energy release rate (GImax) diagram; likewise, this diagram is also obtained under constant amplitude fatigue, and both diagrams are compared to determine the effect of each type of loading on the structural integrity of the joint. Results reveal that the crack propagation rate under impact fatigue is three orders of magnitude greater than that under constant amplitude fatigue.

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