scholarly journals Multiaxial fatigue behavior of SLM Ti6Al4V alloy under different loading conditions

2021 ◽  
Author(s):  
Danilo A. Renzo ◽  
Emanuele Sgambitterra ◽  
Carmine Maletta ◽  
Franco Furgiuele ◽  
Carlo A. Biffi ◽  
...  
Keyword(s):  
Fatigue Behavior ◽  
Multiaxial Fatigue ◽  
Ti6al4v Alloy ◽  
Loading Conditions

Multiaxial fatigue behavior of additively manufactured Ti6Al4V alloy: Axial–torsional proportional loads

2020 ◽  
Author(s):  
Danilo A. Renzo ◽  
Emanuele Sgambitterra ◽  
Pietro Magarò ◽  
Franco Furgiuele ◽  
Carmine Maletta ◽  
...  
Keyword(s):  
Fatigue Behavior ◽  
Multiaxial Fatigue ◽  
Ti6al4v Alloy

scholarly journals Effect of Bond-Line Thickness on Fatigue Crack Growth of Structural Acrylic Adhesive Joints

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1723
Author(s):  
Yu Sekiguchi ◽  
Chiaki Sato
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Behavior ◽  
Adhesive Bond ◽  
Bond Line ◽  
Loading Conditions ◽  
Fatigue Crack Growth Resistance ◽  
Line Thickness ◽  
Bond Line Thickness

With an increasing demand for adhesives, the durability of joints has become highly important. The fatigue resistance of adhesives has been investigated mainly for epoxies, but in recent years many other resins have been adopted for structural adhesives. Therefore, understanding the fatigue characteristics of these resins is also important. In this study, the cyclic fatigue behavior of a two-part acrylic-based adhesive used for structural bonding was investigated using a fracture-mechanics approach. Fatigue tests for mode I loading were conducted under displacement control using double cantilever beam specimens with varying bond-line thicknesses. When the fatigue crack growth rate per cycle, da/dN, reached 10−5 mm/cycle, the fatigue toughness reduced to 1/10 of the critical fracture energy. In addition, significant changes in the characteristics of fatigue crack growth were observed varying the bond-line thickness and loading conditions. However, the predominance of the adhesive thickness on the fatigue crack growth resistance was confirmed regardless of the initial loading conditions. The thicker the adhesive bond line, the greater the fatigue toughness.

Effects of Surface Finish and Loading Conditions on the Low Cycle Fatigue Behavior of Austenitic Stainless Steel in PWR Environment for Various Strain Amplitude Levels

2009 ◽  
Author(s):  
Jean Alain Le Duff ◽  
Andre´ Lefranc¸ois ◽  
Jean Philippe Vernot
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Strain Amplitude ◽  
Surface Finish ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Complex Loading ◽  
Loading Conditions ◽  
Test Results ◽  
Cycle Fatigue

In February/March 2007, The NRC issued Regulatory Guide “RG1.207” and Argonne National Laboratory issued NUREG/CR-6909 that is now applicable in the US for evaluations of PWR environmental effects in fatigue analyses of new reactor components. In order to assess the conservativeness of the application of this NUREG report, Low Cycle Fatigue (LCF) tests were performed by AREVA NP on austenitic stainless steel specimens in a PWR environment. The selected material exhibits in air environment a fatigue behavior consistent with the ANL reference “air” mean curve, as published in NUREG/CR-6909. LCF tests in a PWR environment were performed at various strain amplitude levels (± 0.6% or ± 0.3%) for two loading conditions corresponding to a simple or to a complex strain rate history. The simple loading condition is a fully reverse triangle signal (for comparison purposes with tests performed by other laboratories with the same loading conditions) and the complex signal simulates the strain variation for an actual typical PWR thermal transient. In addition, two various surface finish conditions were tested: polished and ground. This paper presents the comparisons of penalty factors, as observed experimentally, with penalty factors evaluated using ANL formulations (considering the strain integral method for complex loading), and on the other, the comparison of the actual fatigue life of the specimen with the fatigue life predicted through the NUREG report application. For the two strain amplitudes of ± 0.6% and ± 0.3%, LCF tests results obtained on austenitic stainless steel specimens in PWR environment with triangle waveforms at constant low strain rates give “Fen” penalty factors close to those estimated using the ANL formulation (NUREG/6909). However, for the lower strain amplitude level and a triangle loading signal, the ANL formulation is pessimistic compared to the AREVA NP test results obtained for polished specimens. Finally, it was observed that constant amplitude LCF test results obtained on ground specimens under complex loading simulating an actual sequence of a cold and hot thermal shock exhibits lower combined environmental and surface finish effects when compared to the penalty factors estimated on the basis of the ANL formulations. It appears that the application of the NUREG/CR-6909 in conjunction with the Fen model proposed by ANL for austenitic stainless steel provides excessive margins, whereas the current ASME approach seems sufficient to cover significant environmental effects for representative loadings and surface finish conditions of reactor components.

Fatigue behavior and life predictions of thermally oxidized Ti6Al4V alloy according to oxidation parameters

2021 ◽  
pp. 105737
Author(s):  
Gustavo Dória Lima ◽  
Brenno Lima Nascimento ◽  
Isau de Souza Alves Júnior ◽  
Matheus Porto Trindade ◽  
Sandro Griza
Keyword(s):  
Fatigue Behavior ◽  
Ti6al4v Alloy ◽  
Life Predictions ◽  
Oxidation Parameters

High Cycle Fatigue Behavior of Thermally Oxidized Ti6Al4V Alloy

2007 ◽  
Vol 561-565 ◽  
pp. 2179-2182 ◽  
Author(s):  
Mehmet Cingi ◽  
Onur Meydanoglu ◽  
Hasan Guleryuz ◽  
Murat Baydogan ◽  
Huseyin Cimenoglu ◽  
...  
Keyword(s):  
Fatigue Strength ◽  
Yield Strength ◽  
Thermal Oxidation ◽  
Fatigue Behavior ◽  
Surface Hardness ◽  
Ti6al4v Alloy ◽  
Bending Fatigue ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Bending Fatigue Strength

In this study, the effect of thermal oxidation on the high cycle rotating bending fatigue behavior of Ti6Al4V alloy was investigated. Oxidation, which was performed at 600°C for 60 h in air, considerably improved the surface hardness and particularly the yield strength of the alloy without scarifying the tensile ductility. Unfortunately, the rotating bending fatigue strength at 5x106 cycles decreased from about 610 MPa to about 400 MPa upon oxidation. Thus, thermal oxidation leaded a reduction in the fatigue strength of around 34%, while improving the surface hardness (HV0.1) and yield strength 85 % and 36 %, respectively.

scholarly journals Multiaxial fatigue behavior of additive manufactured Ti-6Al-4V under in-phase stresses

2019 ◽  
Vol 18 ◽  
pp. 914-920 ◽  
Author(s):  
Danilo A. Renzo ◽  
Emanuele Sgambitterra ◽  
Pietro Magarò ◽  
Franco Furgiuele ◽  
Carmine Maletta ◽  
...  
Keyword(s):  
Fatigue Behavior ◽  
Multiaxial Fatigue ◽  
Phase Stresses

Influence of Reinforcement Geometry on the Very High-Cycle Fatigue Behavior of Aluminium-Matrix-Composites

2015 ◽  
Vol 825-826 ◽  
pp. 150-157 ◽  
Author(s):  
Alexandra Müller ◽  
Anja Weidner ◽  
Horst Biermann
Keyword(s):  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Aluminum Matrix ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Loading Conditions ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Very High

During technical operation, high performance materials are partially exposed to high frequency cyclic loading conditions. Furthermore, the small strains in the very high cycle fatigue (VHCF)-regime lead to accumulative damage which causes crack initiation related to an appropriate local deformation leading to final fatal fracture. At the same time, quite high requirements with regard to high number of cycles without any damage are demanded for many applications. Fields of application of these light-weight, but expensive materials, are e.g. in the automobile industry (e.g. engine blocks, cylinder heads, brakes).The fatigue behavior of Al-matrix composites (Al-MMCs) reinforced by alumina particles (15 vol.% Al2O3) or short fibers (20 vol.% Saffil), respectively, was already intensively studied in the LCF and HCF range. The present study is focusing on investigations in the very high cycle fatigue regime at stress amplitudes up to 140 MPa to reach fatigue life of about 1010 cycles. All experiments were carried out using an ultrasonic fatigue testing device under symmetric loading conditions (R=-1). Fatigue tests were accompanied by in situ thermography measurements to record the temperature of the whole specimen and to find “hot spots” indicating changes in microstructure and therefore the initiation or growth of cracks. Moreover, the resonant frequency as well as the damage parameter were evaluated to determine the beginning of damage. For a better understanding of the damage mechanism (matrix decohesion, matrix failure or failure of reinforcement) all fractured surfaces were investigated by scanning electron microscopy. The combination of these methods contributes to a better understanding of the underlying mechanism of damage in aluminum-matrix-composites.

Fatigue Behavior of Adhesive Joints Under Biaxial Loading Conditions

1993 ◽  
Author(s):  
Erol Sancaktar
Keyword(s):  
Biaxial Loading ◽  
Fatigue Behavior ◽  
Epoxy Adhesive ◽  
Steel Beams ◽  
Loading Conditions ◽  
Adhesively Bonded Joints ◽  
Shear Loads ◽  
Bonded Joint ◽  
Solid Film ◽  
Static Shear

Abstract Fatigue data obtained under biaxial loading conditions for adhesively bonded joints are used to plot S-N type diagrams to assess the effects of biaxiality in loading. Independently Loaded Mixed-Mode Specimens (ILM MS) are used for data collection purposes. These specimens are basically two (steel) beams bonded to be fatigue loaded under cantilever (opening) mode while a simultaneous but physically separate in-plane (static) shear load is also induced with the aid of a small hydraulic piston embedded in the specimen. Application of such static shear loads results in different S-N behavior for the bonded joint. The model adhesives used are Metlbond 1113-2 and Metlbond 1113 solid film thermosetting adhesives similar to those commonly used in aircraft and aerospace industries. The former is an elastomer-modified epoxy adhesive and the latter is identical except that it containes a synthetic earner cloth. Thus, the effects of carrier cloth in adhesive’s S-N behavior is also assessed. Analytically, the classical linear log-log representation of the adhesive S-N data is explored and modifications necessary to reflect the effects of biaxiality in loading and also the presence of a carrier cloth are assessed. The fatigue failure results are also compared with results obtained under monotonic biaxial loading conditions.

Investigations on the Environmentally Assisted Fatigue Behavior of Steel Specimens for a Better Understanding of Component Fatigue in Nuclear Applications

2021 ◽  
Author(s):  
Christian Swacek ◽  
Ludwig Stumpfrock ◽  
Stefan Weihe
Keyword(s):  
Power Plant ◽  
Fatigue Behavior ◽  
Environmental Influences ◽  
Uniaxial Tensile ◽  
Loading Conditions ◽  
Ongoing Research ◽  
Fatigue Assessment ◽  
Plant Operation ◽  
Power Plant Operation ◽  
Nuclear Applications

Abstract The fatigue assessment of pressurized components is of high importance for the operation of nuclear power plants. However, the environmental influences on the fatigue behavior are highly discussed. On the one hand, laboratory specimens tested in high temperature water (HTW) conditions show a significant drop in fatigue lifetime, compared to tests at air environment, and question the conservatism of modern standards. On the other hand, the fatigue assessment methods based on uniaxial tensile testing seems to overestimate the fatigue damage of components during operation. To overcome these discrepancies, the environmental influences on material fatigue have to be better understood. Laboratory testing setups have to be adapted to the relevant loading conditions during power plant operation. Therefore, MPA Stuttgart is investigating the environmentally assisted fatigue (EAF) of steels under various loading conditions for smooth and notched specimens, as well as full scale component testing at HTW conditions. In this paper the results of ongoing research are presented. The low cycle fatigue experiments on steel materials for relevant nuclear applications are performed at air and under pressurized water reactor (PWR) environment. The shape of specimens, the loading spectra, loading rate and the multiaxiality of load are derived from piping components in power plant operation.

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