scholarly journals Development of a Delamination Fatigue Testing Machine for Composite Materials

Machines ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 27 ◽  
Author(s):  
Pereira ◽  
Fernandes ◽  
de Morais ◽  
Carvalhoso
Keyword(s):  
Composite Materials ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Testing Machine ◽  
Experimental Studies ◽  
Strain Energy Release ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Hydraulic Testing ◽  
Fatigue Tests

Experimental studies on fatigue behavior are usually conducted on servo-hydraulic testing machines that are expensive and have high maintenance costs. In this work, a much simpler testing machine was developed, intended mainly for delamination fatigue tests on composite materials. After a literature review on the methods and parameters of such tests, the machine was designed, and its parts manufactured and assembled into a fully operational testing machine. Additionally, the electrical components and the control and data acquisition software were also developed and implemented. Finally, several mode II delamination fatigue tests were conducted using the end-notched flexure test. The results were consistent with the well-known Paris law, which for composite materials relates the crack propagation rate to the strain-energy release rate range. Therefore, the developed machine seems to be an excellent alternative to the highly costly testing machines.

Gigacycle Fatigue of Welded Joints of Structural Materials (A Review)

2016 ◽  
Vol 17 ◽  
pp. 14-30 ◽  
Author(s):  
Okechukwu P. Nwachukwu ◽  
Alexander V. Gridasov ◽  
Ekaterina A. Gridasova
Keyword(s):  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Testing Machine ◽  
Structural Materials ◽  
Fatigue Tests ◽  
Material Defects ◽  
Graphite Cast Iron ◽  
Ultrasonic Fatigue ◽  
Materials Used ◽  
Fatigue Failures

This review looks into the state of gigacycle fatigue behavior of some structural materials used in engineering works. Particular attention is given to the use of ultrasonic fatigue testing machine (USF-2000) due to its important role in conducting gigacycle fatigue tests. Gigacycle fatigue behavior of most materials used for very long life engineering applications is reviewed.Gigacycle fatigue behavior of magnesium alloys, aluminum alloys, titanium alloys, spheroid graphite cast iron, steels and nickel alloys are reviewed together with the examination of the most common material defects that initiate gigacycle fatigue failures in these materials. In addition, the stage-by-stage fatigue crack developments in the gigacycle regime are reviewed. This review is concluded by suggesting the directions for future works in gigacycle fatigue.

A Study on Fatigue Behavior of SM490A Steel under Low Temperature

2007 ◽  
Vol 353-358 ◽  
pp. 142-145 ◽  
Author(s):  
Ki Weon Kang ◽  
Byeong Choon Goo ◽  
J.H. Kim ◽  
Heung Seob Kim ◽  
Jung Kyu Kim
Keyword(s):  
Fatigue Life ◽  
Low Temperature ◽  
Test Temperature ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Testing Machine ◽  
Fatigue Tests ◽  
Static Strength ◽  
Experimental Results ◽  
Railway Vehicle

This paper deals with the fatigue behavior and its statistical properties of SM490A steel at various temperatures, which is utilized in the railway vehicle. For these goals, the tensile ad fatigue tests were performed by using a servo-hydraulic fatigue testing machine at three temperatures: +20°C, -10°C and -40°C. The static strength and fatigue limits of SM490A steel were increased with decreasing of test temperature. The probabilistic properties of fatigue behavior are investigated by means of probabilistic stress-life (P-S-N) curve and they are well in conformance with the experimental results regardless of temperature. Also, based on P-S-N curves, the variation of fatigue life is investigated and as the temperature decreases, the variation of fatigue life increases moderately.

Surface Topography Influences on the Fatigue Behavior of Composite Joints

2019 ◽  
Vol 809 ◽  
pp. 341-346 ◽  
Author(s):  
Torsten Thäsler ◽  
Jens Holtmannspötter ◽  
Hans Joachim Gudladt
Keyword(s):  
Bond Strength ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Surface Condition ◽  
Atmospheric Pressure Plasma ◽  
Fatigue Tests ◽  
Stress Concentrations ◽  
Release Agent ◽  
Structured Surfaces ◽  
Lap Shear

The surface condition of carbon fibre reinforced plastic (CFRP) substrates is decisive to obtain high bond strength and lifetime of adhesively bonded parts. Those surfaces were adjusted in terms of their microscopic topography by means of peel plies and release foils. The subsequent surface treatment via atmospheric pressure plasma jet or vacuum blasting allowed the modification of the microscopic roughness as well as the surface chemistry. Those configuration were assessed using surface analytic methods as well as quasi-static and cyclic fracture tests on single lap shear specimens. The microscopic surface roughness, if at all, only showed a small influence on the bond strength. Despite release agent residues, fracture was found within the fiber-matrix interface, which caused difficulties in evaluating the effect of surface pretreatments on the adhesion strength. Fatigue tests revealed a lifetime reduction of uneven microscopic rough surfaces, which was assigned to stress concentrations at the tip of asperities. The crack propagation was accelerated in case of release agent residues. If surfaces were free of contaminations, no differences between microscopically smooth and slightly structured surfaces were found. Overall, fatigue testing on single lap shear specimens showed an increased sensitivity with regard to the assessment of surface morphology.

Low Cycle Fatigue Test of Lead Free Solders Using Small Sized Specimen

2017 ◽  
Vol 734 ◽  
pp. 194-201 ◽  
Author(s):  
Yutaka Konishi ◽  
Takamoto Itoh ◽  
Masao Sakane ◽  
Fumio Ogawa ◽  
Hideyuki Kanayama
Keyword(s):  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
Testing Machine ◽  
Strain Range ◽  
Fatigue Tests ◽  
Lead Free ◽  
Cycle Fatigue ◽  
Bulk Specimen ◽  
Free Solder ◽  
Lead Free Solders

This paper investigates the fatigue results in low cycle fatigue region obtained from a miniaturized specimen having a 6mm gage length, 3mm diameter and 55mm total length. Fatigue tests were performed for two type lead-free solders using horizontal-type electrical servo hydraulic push-pull fatigue testing machine. Materials employed were Sn-3.0Ag-0.5Cu and Sn-5Sb. The results from Sn-3.0Ag-0.5Cu were compared with those obtained using a bulk specimen in a previous study. Relationship between strain range and number of cycles to failure of the small-sized specimen agreed with those of the bulk specimens. The testing techniques are applicable to Sn-5Sb following the Manson-Coffin law. These results confirm that the testing technique proposed here, using small-sized specimen, is suitable to get fruitful fatigue data for lead-free solder compounds.

Simulation of Cracks in Fiber Reinforced Composite Plate

2011 ◽  
Vol 471-472 ◽  
pp. 892-897 ◽  
Author(s):  
Pramod Kumar ◽  
Ashish Kakyal
Keyword(s):  
Cyclic Loading ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fem Analysis ◽  
Strain Energy Release ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Fiber Reinforced ◽  
Automotive Parts ◽  
Mechanical Approach

Material flaws, pre-cracks and crack initiation due to cyclic loading often lead to undetected crack propagation in commercial structures like aircraft components, automotive parts and computer motherboard. Cyclic loading can make the crack grow large into any shape with an arbitrary orientation, depending on the structure geometry, boundary and loading conditions. Since crack propagation in many cases may lead to catastrophic failure with human and monetary loss as a result, it is important to enable crack growth prediction at all stages of development and during maintenance in order to prevent such scenarios. Micro mechanical approach is used for modelling the crack in composite materials. Crack propagation in a single edge crack plate is carried out by using FEM analysis. 2D model is analysed to determine the crack growth. The crack propagation rate, stress intensity factor and strain energy release rate are predicted by varying the crack length in fiber reinforced epoxy composite using NISA/ENDURE.

Development of a New Fatigue Testing Machine for High Frequency Fatigue Damage Assessment

2013 ◽  
Author(s):  
Naoki Osawa ◽  
Tetsuya Nakamura ◽  
Norio Yamamoto ◽  
Junji Sawamura
Keyword(s):  
High Frequency ◽  
High Speed ◽  
Fatigue Testing ◽  
Low Cost ◽  
Plate Thickness ◽  
Testing Machine ◽  
Fatigue Tests ◽  
Frequency Effect ◽  
Wave Load ◽  
Out Of Plane

A new simple fatigue testing machine, which can carry out fast and low-cost fatigue tests of welded joints subject to wave with high frequency vibration, has been developed. This machine is designed for plate bending type fatigue tests, and wave load is applied by using motors with eccentric mass. Springing vibration is superimposed by attaching an additional vibrator to the test specimen, and whipping vibration is superimposed by an intermittent hammering. Fatigue tests which simulate springing and whipping by a conventional servo-type fatigue testing machines are very expensive and use a large amount of electricity. If one uses these conventional machines, it is difficult to simulate superimposed stress wave forms at high speed, and it takes long hours of testing to examine the high frequency effect. In contrast, it is found that fatigue tests can be carried out in fast, i.e. waves with 10Hz or higher frequency for out-of-plane gusset welded joint specimens with 12mm plate thickness by using the developed machine. The electricity to be used for fatigue tests could be minimal, for example one thousandth of that needed for conventional machines. These results demonstrate the superiority of the developed machine.

High-Cycle-Fatigue Characterization of an Additive Manufacturing 17-4 PH Stainless Steel

2021 ◽  
Vol 877 ◽  
pp. 49-54
Author(s):  
Lorenzo Maccioni ◽  
Lorenzo Fraccaroli ◽  
Yuri Borgianni ◽  
Franco Concli
Keyword(s):  
Stainless Steel ◽  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
Crack Nucleation ◽  
High Surface ◽  
Testing Machine ◽  
Volume Ratio ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
Traction Test

On the one hand, many mechanical components manufactured through additive technologies are optimized in terms of stiffness/weight or strength/weight thanks to lattice structures. On the other hand, the high complexity of these components often impedes further finishing operations and, therefore, the fatigue strength can be compromised. The high surface to volume ratio together with the high roughness, typical of additive manufactured components, promote the crack nucleation. In this paper, the High-Cycle-Fatigue (HCF) behavior of the 17-4 PH stainless steel (SS) was characterized. Cylindrical samples, manufactured via Selective Laser Melting (SLM) with an EOS M280, were tested in the as-build condition through a STEPLab UD04 fatigue-testing machine. In particular, a preliminary quasi-static traction test was performed on a sample to obtain the yield strength (σY = 570 MPa) and the ultimate tensile strength (UTS = 1027 MPa). Fatigue tests were performed on samples at different stress levels in order to characterize the whole Stress-Number of cycles (S-N) curve (Wöhler diagram). More specifically, the stair-case method combined with the Dixon approach were exploited to calculate the fatigue limit (σF = 271 MPa). The obtained results were compared with those present in literature for the same material and they are coherent with previous researches

An X-Ray Investigation of Fatigue Behavior of Cold Worked Aluminum

1972 ◽  
Vol 16 ◽  
pp. 354-366
Author(s):  
R. W. Gould ◽  
C. F. Pittella
Keyword(s):  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Diffraction Method ◽  
Domain Size ◽  
Fatigue Tests ◽  
Line Profile Analysis ◽  
Bending Stress ◽  
X Ray ◽  
Cold Worked ◽  
Effective Domain

AbstractDouble bending fatigue tests were performed on cold worked 1100 aluminum, with a maximum bending stress varying from 100 to 50% of the yield stress. Variation of residual macrostress from the cold worked state during the fatigue tests was measured by the photographic x-ray diffraction method. A general decrease of this macrostress was observed. Line profile analysis was used to study the change in the mean effective domain size and microstrain. A rate dependence of the increase in the effective domain size with respect to the maximum bending stress was observed. Microhardness and tensile tests were also made on the specimens during the fatigue testing and the results are correlated with the x-ray Parameters.

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