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Grellmann, W.; Lach, Ralf; Seidler, Sabine

doi:10.1023/a:1022606804824

Cited by 10 publications

(6 citation statements)

References 10 publications

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“…The G IC values for the bulk fracture samples with edge crack were determined using the K‐calibration equation:

{normalK}_{I C} B w ∖ {normalP}_{normalc} {normala}^{1 ∖ 2} = 1.99 - 0.41 true(normala ∖ normalw true) + 18.7 {(a ∖ w)}^{2} - 38.4 {(a ∖ w)}^{3} + 53.85 {true(normala ∖ normalw true)}^{4}

where w is the specimen width and a is the crack length including the notch and the starter crack. Examination of the literature reveals that the minimum values for specimen thickness and crack length are given by:

a, B \geq 2.5 {({normalK}_{I C} ∖ {normalσ}_{normaly})}^{2}

…”

Section: Methodsmentioning

confidence: 99%

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Fracture Behavior of Epoxy Resins in Fabric‐Supported Form

Sancaktar

2017

Macromolecular Symposia

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Summary Elastic‐plastic fracture behavior of a structural adhesive in the bulk and bonded forms is discussed. The model adhesive chosen with and without scrim carrier cloth (neat resin) solid film adhesives exhibit a relatively brittle material behavior to justify the use of Linear Elastic Fracture Mechanics (LEFM) methods. The solid film adhesives are first cast in the form of tensile coupons to determine the bulk fracture properties with the use of single‐edge‐cracked specimen geometry. KIC evaluation is done using the procedure suggested by the ASTM standard. A K‐calibration method based on application of boundary collocation procedure to the William's stress function is utilized to relate the measured critical loads to the KIC values. The yield stresses (σY) and elastic moduli (E) values in the bulk tensile mode are also evaluated. The availability of KIC, σY, E and ν (Poisson's ratio) values makes the calculation of crack tip plastic zone radii (rYC) and fracture energy (GIC) values possible on the basis of Irwin's theory. The bulk casting procedure is done under different cure (temperature, time and cool‐down) conditions to determine optimum properties. We found that the most suitable model that would fit the stress‐strain response of the model adhesives with prediction of the stress whitening stress level, σ*, under material damage surrounding flaws and crack tips was a modified version of Ramberg‐Osgood equation. A bilinear behavior is obtained when log(ϵp) is plotted against log(σ – Θ). The plastic strain ϵp is assumed to be a function of the over‐stress above the elastic limit stress, Θ, and the stress levels defining the intersection point for the bilinear behavior are found to occur slightly below the stress whitening stress values.

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“…The G IC values for the bulk fracture samples with edge crack were determined using the K‐calibration equation:

{normalK}_{I C} B w ∖ {normalP}_{normalc} {normala}^{1 ∖ 2} = 1.99 - 0.41 true(normala ∖ normalw true) + 18.7 {(a ∖ w)}^{2} - 38.4 {(a ∖ w)}^{3} + 53.85 {true(normala ∖ normalw true)}^{4}

a, B \geq 2.5 {({normalK}_{I C} ∖ {normalσ}_{normaly})}^{2}

…”

Section: Methodsmentioning

confidence: 99%

“…where w is the specimen width and a is the crack length including the notch and the starter crack. Examination of the literature [14][15][16] reveals that the minimum values for specimen thickness and crack length are given by:…”

Section: Methodsmentioning

confidence: 99%

Fracture Behavior of Epoxy Resins in Fabric‐Supported Form

Sancaktar

2017

Macromolecular Symposia

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“…In the equation, K IC is the fracture toughness (MPa•m 1/2 ), R y is the yield strength (N/mm 2 ), and 2.5 is a commonly used geometrical constant. For the polymers, the values of the geometrical constant were experimentally determined over a very wide range from 0.24 to 26 [27], but the general known value is sufficient for SAN [2]. Because of the fact that R y ≈ R m , for brittle polymers, Equation (8) can be written as:…”

Section: Estimation Of the Crack-growth Conditionsmentioning

confidence: 99%

Effect of the Shape of Styrene–Acrylonitrile Water-Filter Housings on the Destructive Pressure, Crack-Initiation, Propagation Conditions and Fracture Toughness of Styrene–Acrylonitrile

Zorc

Kosec

et al. 2020

Polymers

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A destructive pressure test of styrene–acrylonitrile (SAN) water-filter housings showed the influence of the shape and specific details of the housings on their critical areas and their destructive pressure. The destructive pressure varies by as much as 37 bar due to different dominant stresses in the individual types of housings. In critical areas of the housings, geometrical stress concentrators generally exist. For this reason, the stress caused by the internal pressure is locally 2.75–3.4 times greater than that expected based on the water pressure, which means that cracks are initiated in these places. However, the bottom of the housings can be in a form such that the maximum stress and the crack originates in its central part without the influence of local stress concentrators. The tensile strength of the SAN is theoretically estimated at 73 N/mm2, which is comparable with the literature data. The fracture toughness of the SAN is typically low, theoretically estimated in the range 1.45–3.55 MPa·m1/2, and strongly depends on the degree of the wall’s stress-increasing rate or the crack-propagation rate. Therefore, at various crack-propagation rates, the critical crack depths are also different, in the range 100–600 μm. Due to this, the critical thickness for brittle fracture in the SAN is also different; it is ten times greater than the critical crack length. The characteristic of a sub-critical crack, i.e., the mirror zone, is its macroscopically smooth surface, which is microscopically very finely roughened. In the case of a sufficiently slowly growing sub-critical crack, the surface of the mirror zone contains characteristic parabolic markings. The over-critical, sufficiently rapidly growing cracks generally grow mainly in the plane-strain state and only the final thin layer of the remaining wall thickness breaks in the plane-stress state. The over-critical, sufficiently slowly growing cracks grow in the plane-stress state with a strong shear plastic tearing.

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“…As described within the experimental part of this article, the specimen geometry has to fulfill some requirements. [28][29][30] For checking the geometry independence, the geometrical factors b, n, and e were determined after rearranging eq. (8)(9)(10).…”

Section: Fracture Behavior Of Glass Fiber Reinforced Thermoplasticsmentioning

confidence: 99%

Characterization of the fracture behavior of glass fiber reinforced thermoplastics based on PP, PE‐HD, and PB‐1

Schoßig¹,

Grellmann²,

Mecklenburg³

2009

J of Applied Polymer Sci

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This article deals with the influence of the polymeric matrix, such as isotactic polypropylene (iPP), polyethylene (PE-HD), and isotactic polybutene-1 (iPB-1), and the glass fiber content on the material behavior of short glass fiber reinforced thermoplastics. The glass fiber content of all materials ranged between 0 and 50 wt %, which corresponds to a volume content between 0 and approx. 0.264. To describe the mechanical properties of all materials, the stiffness, strength, hardness, and toughness behavior were determined. The crack toughness behavior regarding unstable crack propagation was also assessed by applying fracture mechanics concepts. It was found that the energy-determined J-values for the PP material system reach their maximum at a glass fiber content of 0.135. In contrast, the crack toughness of the PE-HD materials increases continuously with increasing glass fiber content due to the unchanged deformation ability at simultaneously increasing strength. The toughness level of the PB-1 materials is nearly the same independent of the glass fiber content due to the opposite trend of the load and the deformation ability.

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Cited by 10 publications

References 10 publications

Fracture Behavior of Epoxy Resins in Fabric‐Supported Form

Fracture Behavior of Epoxy Resins in Fabric‐Supported Form

Effect of the Shape of Styrene–Acrylonitrile Water-Filter Housings on the Destructive Pressure, Crack-Initiation, Propagation Conditions and Fracture Toughness of Styrene–Acrylonitrile

Characterization of the fracture behavior of glass fiber reinforced thermoplastics based on PP, PE‐HD, and PB‐1

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