Yield Behavior of Gelled Waxy Oil: Effect of Stress Application in Creep Ranges

2009 ◽  
Vol 48 (19) ◽  
pp. 8950-8953 ◽  
Author(s):  
Kyeongseok Oh ◽  
Mark Jemmett ◽  
Milind Deo
Keyword(s):  
Yield Behavior ◽  
Waxy Oil ◽  
Stress Application

Micromechanically based formulation of the cooperative model for the yield behavior of semi-crystalline polymers

2008 ◽  
Vol 56 (7) ◽  
pp. 1650-1655 ◽  
Author(s):  
O. Gueguen ◽  
J. Richeton ◽  
S. Ahzi ◽  
A. Makradi
Keyword(s):  
Yield Behavior ◽  
Cooperative Model ◽  
Crystalline Polymers

Magnesium Sheet Metal Forming Considering its Specific Yield Behavior

2005 ◽  
Vol 6-8 ◽  
pp. 771-778 ◽  
Author(s):  
M. Redecker ◽  
Karl Roll ◽  
S. Häussinger
Keyword(s):  
Sheet Metal ◽  
Elevated Temperatures ◽  
Flow Behavior ◽  
Specific Yield ◽  
Forming Limit ◽  
Forming Process ◽  
Local Flow ◽  
Yield Behavior ◽  
Magnesium Sheet ◽  
Testing Procedures

In recent years very strong efforts have been undertaken to build light weight structures of car bodies in the automotive industry. Structural technologies like Space Frame, tailored blanks and relief-embossed panels are well-known and already in use. Beside that there is a large assortment of design materials with low density or high strength. Magnesium alloys are lighter by approximately 34 percent than aluminum alloys and are considered to be the lightest metallic design material. However forming processes of magnesium sheet metal are difficult due to its complex plasticity behavior. Strain rate sensitivity, asymmetric and softening yield behavior of magnesium are leading to a complex description of the forming process. Asymmetric yield behavior means different yield stress depending on tensile or compressive loading. It is well-known that elevated temperatures around 200°C improve the local flow behavior of magnesium. Experiments show that in this way the forming limit curves can be considerably increased. So far the simulation of the forming process including temperature, strain rates and plastic asymmetry is not state-of-the-art. Moreover, neither reliable material data nor standardized testing procedures are available. According to the great attractiveness of magnesium sheet metal parts there is a serious need for a reliable modeling of the virtual process chain including the specification of required mechanical properties. An existing series geometry which already can be made of magnesium at elevated temperatures is calculated using the finite element method. The results clarify the failings of standard calculation methods and show potentials of its improvement.

Effect of Interfacial Properties on the Mechanical Behavior of Bone-Like Materials: A Numerical Study

2017 ◽  
Vol 09 (01) ◽  
pp. 1750014 ◽  
Author(s):  
Xingguo Li ◽  
Bingbing An ◽  
Dongsheng Zhang
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Numerical Study ◽  
Element Model ◽  
Interfacial Behavior ◽  
Yield Behavior ◽  
Bonding Property ◽  
The Matrix ◽  
Bonding Properties ◽  
Superior Mechanical Properties

Interfacial behavior in the microstructure and the plastic deformation in the protein matrix influence the overall mechanical properties of biological hard tissues. A cohesive finite element model has been developed to investigate the inelastic mechanical properties of bone-like biocomposites consisting of hard mineral crystals embedded in soft biopolymer matrix. In this study, the complex interaction between plastic dissipation in the matrix and bonding properties of the interface between minerals and matrix is revealed, and the effect of such interaction on the toughening of bone-like biocomposites is identified. For the case of strong and intermediate interfaces, the toughness of biocomposites is controlled by the post yield behavior of biopolymer; the matrix with low strain hardening can undergo significant plastic deformation, thereby promoting enhanced fracture toughness of biocomposites. For the case of weak interfaces, the toughness of biocomposites is governed by the bonding property of the interface, and the post-yield behavior of biopolymer shows negligible effect on the toughness. The findings of this study help to direct the path for designing bioinspired materials with superior mechanical properties.

Effect of Interface Conditions on Yield Behavior of Passivated Copper Thin Films

2002 ◽  
Vol 17 (7) ◽  
pp. 1863-1870 ◽  
Author(s):  
Richard P. Vinci ◽  
Stefanie A. Forrest ◽  
John C. Bravman
Keyword(s):  
Thin Films ◽  
Driving Force ◽  
Copper Film ◽  
Dislocation Motion ◽  
Yield Behavior ◽  
Dislocation Glide ◽  
Preferential Diffusion ◽  
Continuous Vacuum ◽  
And Diffusion ◽  
Induced Dislocation

Wafer curvature was used to study the thermal–mechanical behavior of 1-μm Cu thin films capped with a 100-nm-thick Si3N4 layer. These films were grown with either a Ta or a Si3N4 underlayer. Films on Si3N4 that were exposed to oxygen at the film/capping layer interface or at the center of the copper layer exhibited Bauschinger-like yielding at low stress. Stacks deposited under continuous vacuum, with a Ta underlayer, with carbon exposure at the upper surface of the copper film, or with oxygen exposure of only the underlayer did not demonstrate the anomalous yielding. Preferential diffusion of oxygen into copper grain boundaries or interfaces is the likely cause of the early yield behavior. Possible mechanisms include an increase in interface adhesion due to the presence of oxygen in solution and diffusion-induced dislocation glide as an additional driving force for dislocation motion at low applied stress.

Yield behavior of random copolymers of isotactic polypropylene

Polymer ◽  
2017 ◽  
Vol 129 ◽  
pp. 235-246 ◽  
Author(s):  
Finizia Auriemma ◽  
Claudio De Rosa ◽  
Rocco Di Girolamo ◽  
Anna Malafronte ◽  
Miriam Scoti ◽  
...  
Keyword(s):  
Isotactic Polypropylene ◽  
Random Copolymers ◽  
Yield Behavior
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