Die arc sin √P‐Transformation — ein einfaches Verfahren zur grafischen und rechnerischen Auswertung geplanter Wöhlerversuche

Dengel, D.

doi:10.1002/mawe.19750060803

Cited by 79 publications

(21 citation statements)

References 13 publications

(1 reference statement)

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“…Das auf Fisher [198] zurückgehende und von Dengel [191] fortgeführte arcsin-Verfahren ähnelt in der Versuchsdurchführung dem Abgrenzungsverfahren. Jedoch wird auf mehr als zwei Spannungshorizonten geprüft.…”

Section: Arcsin-verfahrenunclassified

Ermüdungsfestigkeit

2007

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Section: Arcsin-verfahrenunclassified

Ermüdungsfestigkeit

2007

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“…The slower crack propagation is a result of the greater distances between individual fibers at lower fiber volume fractions. With increasing distance the "notch effect" a cracked fiber has on its neighbours gets reduced (4,8,9). Microscopic images show that at a fiber volume fraction of u = 0.5 (in contrast to u= 0.6) there are frequently resin rich regions in between the closely packed fiber bundles.…”

Section: Results -Comparison Of Fatigue Lifesmentioning

confidence: 98%

“…10 the fatigue life of the individual specimen is presented in a S-N diagram. The area of scattering from 5% up to 95% error probability was calculated by arcsin P 1/2 -transformation according to [8], which is applied as experimental evaluation method for the statistical assessment of fatigue tests. The strain e || is not the amplitude, but the maximum tension strain in the boundary layer.…”

Section: Results -Comparison Of Fatigue Lifesmentioning

confidence: 99%

Fatigue behaviour of glasfiber‐thermosets; reasons and improvements

Schuermann¹

2011

Materialwissenschaft Werkst

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Dedicated to Prof. Holger Hanselka on the occasion of his 50 th birthday. H. SchuermannMechanisms are presented which occur in unidirectional fiber reinforced plastics due to fiber fracture and subsequent crack evolution. The 3-point-bending test was chosen as test method and the analyses are predominantly carried out by microscopy. It is shown that the matrix system, the fiber-matrix interface adhesion strength and the fiber volume fraction are of great importance for improving fatigue strength. The results can be transferred directly to high stressed bending structures such as leaf springs.Keywords: Unidirectional fiber reinforced plastics / bending fatigue tests / failure evolution / IntroductionIn comparison to other materials fiber reinforced plastics (FRP) exhibit outstanding stiffness and strength when stressed in fiber direction. Therefore FRPs are preferred for structures which are predominantly loaded by uniaxial normal stresses, e. g. tension/ compression-rods and slim bending structures such as leaf springs.In the last 15 years intensive research proofed leaf springs made of glass-fiber reinforced epoxies as superior to conventional steel leaf springs [1,2]. The failure developement of FRP leaf springs is known as absolutely forgiving. The high stress gradient in bending and the ply's crack stopper effect restricts the crack initiation to the boundary layers of the spring. In addition the cracks grow very slowly and are particularly detectable visually, Fig. 1. Of special interest is the high weight reduction only by changing the material from steel to fiber reinforced plastics.So a rear-axle spring of a 24t-truck made of steel weights 84 kg, the one made of FRP only 19 kg. This weight reduction of the rear-axle of totally 130 kg is hardly to achieve as simple with another approach.The ecological importance of the FRP-spring is even higher. In 2005 about 2.6 million trucks were registered in Germany. Mounting all these trucks with lightweight FRP leaf springs instead of steel springs would reduce the mass in the range of 52 000 t. Assuming an annual averaged driving performance of 50 000 km and a saving of 1.5 l fuel per 1 t mass-reduction per 100 km, the modification would yield to a fuel-saving of about 39 million litres per year. This is an extensive reduction of CO 2 emission. For this reasons it is indispensable to push ahead this lightweight approach consequently.However, till now the true mechanism of the failure on the micromechanical level, which leads to the good-natured failure, is unknown. The assumption is dominant, only the fatigue behaviour of the fiber counts for this, since the longitudinal load is almost totally born by the fibers. Hence the effect of the matrix on this fatigue case is classified as negligible. But distinct differences in the cyclic strength of the same fiber but different matrixsystems suggest a strong influence of the matrix.In a comprehensive research project of the institute Konstruktiver Leichtbau und Bauweisen at TU Darmstadt the failure mechanism due to cycli...

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“…Fur die statistische Auswertung der Versuchsergebnisse wurde die in den letzten Jahren zunehmend venvendete arc sin p-Transformation angewendet [19]. Der besondere Vorteil dieser Transformation besteht darin, daB die Varianz der TransformationsgroBe x = arc sin fl (P. .Bruchwahrscheinlichkeit) rnit steigender Zahl x (= Stichprobenumfang n) asymptotisch einem konstanten Wert zustrebt, also bereits bei einer relativ geringen Anzahl von Proben von n unabhlngig wird.…”

Section: Versuchsdurchfuhrung Und Auswertung Der Versuchsergebnisseunclassified

Schwingfestigkeitseigenschaften von Schweißverbindungen hochfester, schweißgeeigneter Baustähle

Prior¹,

Maurer

1995

Materialwissenschaft Werkst

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Fatigue strength properties of welded joints of high-strength weldable structural steel.Particularly with regard to weld joints, high-strength and super high-strength structural steels under unfavourable boundary conditions is hardly superior to normal-strength steel. These studies aim at analyzing whether the fatigue strength characteristics of butt joint and cruciform joint samples can be improved by optimizing the weld seam geometry and by subsequent mechanical treatment by shot peening with ceramic balls or with steel scraps, and at determining which difficulties may occur during this process. The practical tests were supported and completed by theoretical calculations according to the FE-method. A final comparison with the standards will illustrate the difficulties in determining admissible fatigue strength values of weld joints.

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Die arc sin √P‐Transformation — ein einfaches Verfahren zur grafischen und rechnerischen Auswertung geplanter Wöhlerversuche

Cited by 79 publications

References 13 publications

Ermüdungsfestigkeit

Ermüdungsfestigkeit

Fatigue behaviour of glasfiber‐thermosets; reasons and improvements

Schwingfestigkeitseigenschaften von Schweißverbindungen hochfester, schweißgeeigneter Baustähle

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