An investigation of fracture criteria for predicting surface fracture in paste extrusion

Domanti, A.T.J.; Horrobin, D.J.; Bridgwater, J.

doi:10.1016/s0020-7403(02)00047-4

Cited by 24 publications

(15 citation statements)

References 10 publications

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“…This means that using this die shape tends to generate the surface cracks. This conclusion does not agree with other researcher's work [27]. However, it can be interpreted from the following two aspects that: (1) at the beginning of extrusion, the material which forms the extrudate surface has experienced a longer contact length with the stream line die than with other die configurations.…”

Section: Prediction Of Surface Crackscontrasting

confidence: 69%

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Application of finite element method in the hot extrusion of aluminium alloys

Duan

Velay

Sheppard

2004

Materials Science and Engineering: A

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Section: Prediction Of Surface Crackscontrasting

confidence: 69%

“…Clift et al [25], Ko et al [26] and Domanti et al [27] have indicated that the Cockcroft and Latham criterion [28] is the best amongst the various existing criteria for the prediction of fracture initiation for extrusion.…”

Section: Prediction Of Surface Cracksmentioning

confidence: 99%

Application of finite element method in the hot extrusion of aluminium alloys

Duan

Velay

Sheppard

2004

Materials Science and Engineering: A

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“…Many researchers have used the Cockcroft and Latham criterion [11] for the prediction of fracture initiation during extrusion [12][13][14]. The normalized form of the Cockcroft and Latham criterion can be expressed as in the following: (1) where is equivalent stress, σ I the maximum principal tensile stress, the equivalent strain, the equivalent strain to fracture, and CL is the critical damage value [15].…”

Section: Surface Crack Prediction Of Extruded Bar Using Fem Simulationmentioning

confidence: 99%

Effect of scandium on the hot extrudability of 7075 aluminum alloy

et al. 2010

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This study investigated the effect of the addition of scandium on the hot extrudability of 7075 alloys. Three kinds of Al-Zn-Mg-(Sc) alloys with up to 0.30 wt.% Sc were prepared, including 7075 aluminum alloy without Sc (AA7075). Differential scanning calorimetry (DSC) analyses and hot compression tests were conducted to examine the incipient melting temperature of the alloys produced. The addition of 0.30 wt.% Sc resulted in significant grain refinement and a fully equiaxed microstructure. Hot compression tests were conducted to determine the critical damage values based on Cockroft-Latham criterion. Then, the surface quality of an extruded bar of each alloy was simulated with a finite element code. The surface condition of an extruded bar was predicted and compared with the experimental results. After hot extrusion, AA7075 without the addition of Sc showed a more moderate surface quality than the alloys modified with Sc. However, AA7075 revealed coarse-grained bands just below the surface area. Extrusion limit diagrams were constructed for the three alloys.

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“…For the experiments the die presented an abrupt contraction (angle of the die entry equal to 908), as this type of die gave the worst conditions for the formation of surface fractures at the die angle. 20 Such a die imposed high extrusion stress and led to important drainage effects on the selected mortar.…”

Section: Screw Extrusion -Vibro-extruder Developmentmentioning

confidence: 99%

Vibro-extrusion: a new forming process for cement-based materials

Perrot

Mélinge

Estellé

et al. 2009

Advances in Cement Research

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International audienceExtrusion is a common forming process for a wide range of materials (food, polymer, clay, metal), although it is not yet a common way to form cement-based materials on an industrial scale. This is both explained by the heterogeneity (large range of grain size) and the specific rheological behaviour (frictional behaviour due to high solid volume fraction) of such materials. Recent studies have highlighted the predominance of the filtration phenomenon during the extrusion flow of firm cement-based materials. Such a filtration leads to process blockage and prohibits its utilisation in industrial settings. In the present study the introduction of a vibration system to the extruder in order to inprove the extrusion flow was investigated. The effects of such external excitation on the rheological behaviour of a firm extrudible cement-based paste (yield stress reduction without losing retaining shape properties) were examined and some extrusion tests (ram and screw extruders) were performed to show the potential of a vibration/extrusion coupling

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An investigation of fracture criteria for predicting surface fracture in paste extrusion

Cited by 24 publications

References 10 publications

Application of finite element method in the hot extrusion of aluminium alloys

Application of finite element method in the hot extrusion of aluminium alloys

Effect of scandium on the hot extrudability of 7075 aluminum alloy

Vibro-extrusion: a new forming process for cement-based materials

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