Modeling of the Mechanical Response During Reversal Shear Loading: Application to Steels

2015 ◽  
Vol 87 (7) ◽  
pp. 850-858 ◽  
Author(s):  
Wei Wen ◽  
Marina Borodachenkova ◽  
Frédéric Barlat ◽  
Juan Liao ◽  
José Joaquim Grácio
2018 ◽  
Vol 27 (3-4) ◽  
Author(s):  
Ermioni D. Pasiou ◽  
Stavros K. Kourkoulis

AbstractThe mechanical response of the restored “connections” of the epistyles of the Parthenon Temple on the Acropolis of Athens is studied assuming that the interconnected epistyles are under shear loading mode. The study is implemented by taking advantage of a numerical model, properly validated on the basis of the data of a recent relative experimental protocol. The main difficulty while studying the specific problem is the co-existence of three materials of completely different mechanical behaviors, i.e. the brittle marble of the epistyles, the ductile titanium of the connector and the cement-based material filling the grooves of the marble in which the connector is placed. The interfaces of this three-material-complex are simulated as simple contact with friction, the coefficient of which is, also, experimentally determined. Taking advantage of the data provided by the numerical model the stress field developed in the connector and the surrounding marble volume is described. Moreover, the forces imposed by the connector on the surface of the groove are quantitatively determined. Furthermore, the model permits a quantitative comparison between the mechanical response of the interconnected epistyles in the presence or in the absence of the “relieving space”. It is definitely concluded that the alternative design of the “connections”, according to which a small portion of the connector’s web is left uncovered by the filling material (relieving space), offers serious advantages against the traditional design, in the direction of reducing the intensity of the stress field developed in the marble volume surrounding the connector, thus, contributing to the protection of the authentic building material of the monument in the case of overloading of the epistyles.


Author(s):  
Huaning Zhu ◽  
Morteza M. Mehrabadi ◽  
Mehrdad Massoudi

The principal objective of this paper is to compare the mechanical response of a double shearing model with that of a hypoplastic model under biaxial compression and under cyclic shear loading. As the origins and nature of these two models are completely different, it is interesting to compare the predictions of these two models. The constitutive relations of the double shearing and the hypoplastic models are implemented in the finite element program ABACUS/Explicit. It is found that the hypoplastic and the double shearing constitutive models both show strong capability in capturing the essential behavior of granular materials. In particular, under the condition of non-cyclic loading, the stress ratio and void ratio predictions of the double shearing and the hypoplastic models are relatively close, while under the condition of cyclic loading, the predictions of these models are quite different. It is important to note that in the double shearing model employed in this comparison the shear rates on the two slip systems are assumed to be equal. Hence, the conclusions derived in this comparison pertain only to this particular double shearing model. Similarly, the hypoplasticity model considered here is that proposed by Wu, et al. [30] and the conclusions reached here pertain only to this particular hypoplasticity model.


Author(s):  
Pavana Sirimamilla ◽  
Ahmet Erdemir ◽  
Antonie J. van den Bogert ◽  
Jason P. Halloran

Experimental testing of cadaver specimens is a useful means to quantify structural and material response of tissue and passive joint properties against applied loading[1,4]. Very often, specific material response (i.e., stress-strain behavior of a ligament or plantar tissue) has been the goal of experimental testing and is accomplished with uniaxial and/or biaxial tests of prepared tissue specimens with uniform geometries[2,5]. Material properties can then be calculated directly and if testing data involves individual sets of multiple loading modes (e.g. compression only, shear only, volumetric) an accurate representation of the global response of the specimen may be possible. In foot biomechanics, however, it is practically impossible to perform isolated mechanical testing in this manner. The structural response, therefore the stiffness characteristics, of the foot have been quantified, usually using a dominant loading mode: e.g., whole foot compression [6], heel pad indentation [3]. This approach ignores the complexity of most in vivo loading conditions, in which whole foot deformation involves interactions between compression, shear (e.g. heel pad) and tension (e.g. ligaments). Therefore, the purpose of this study was to quantify the mechanical response of a cadaver foot specimen subjected to compression and anterior-posterior (AP) shear loading of isolated heel and forefoot regions as well as whole foot compression. Results from the experimental tests represent a novel methodology to quantify a complete structural biomechanical response. Combined with medical imaging, followed by inverse finite element (FE) analysis, the data may also serve for material characterization of foot tissue.


2007 ◽  
Vol 44 (4) ◽  
pp. 436-446 ◽  
Author(s):  
James Blatz ◽  
David E.S Anderson ◽  
Greg Siemens

This paper examines and compares the mechanical behaviour of two different unsaturated clay mixtures comprised of bentonite clay (Saskatchewan or Wyoming) and quartz sand. The two mixtures have been proposed as compacted barrier materials for reducing groundwater flow in the vicinity of waste disposal repositories. Triaxial specimens were compacted to consistent properties, and then specified suction conditions were applied to the specimens using the vapour equilibrium technique. Following equilibrium at the specified initial suction, specimens were subjected to isotropic and shear loading in a conventional triaxial cell to measure the mechanical response under selected stress paths. The results are interpreted in terms of the yield, strength, and stiffness behaviour at the various suction levels. Results suggest that the clay component of the mixture dominates the behaviour at suctions less than approximately 30 MPa, and the sand component dominates the behaviour above approximately 30 MPa. The transition from clay- to sand-dominated behaviour is attributed to volume strain during application of the initial suction bringing the sand particles into contact. The discussion highlights how the results can be used to modify constitutive models to incorporate the transitional behaviour in numerical modeling.Key words: inelastic, yielding, unsaturated, stress–strain, triaxial testing.


2010 ◽  
Vol 47 (5) ◽  
pp. 552-565 ◽  
Author(s):  
Ali Khalili ◽  
Dharma Wijewickreme ◽  
G. Ward Wilson

The idea of mixing mine tailings and waste rock to form “paste rock” prior to disposal is now receiving significant attention from the point of view of sustainable mine waste management practices. This approach has been viewed as a favourable alternative to traditional methods of mine waste disposal because paste rock has the potential to overcome deficiencies (e.g., acid rock drainage and liquefaction-induced failures) associated with traditional methods. To advance the current limited knowledge, a laboratory research program was undertaken to study the mechanical response of paste rock. Testing was undertaken on paste rock specimens prepared so that the tailings would “just fill” the void spaces within the waste rock particle skeleton. The findings suggest that the material is unlikely to experience flow deformation under monotonic shear loading conditions, at least up to the tested initial effective confining stress conditions of 400 kPa. The monotonic shear response of paste rock was found to be similar to that of rock-only material; this finding is in agreement with previous observations from one-dimensional consolidation testing where it had been shown that the rock particle skeleton would carry almost 90% of the externally applied stress on a given paste rock mass.


1989 ◽  
Vol 8 (4) ◽  
pp. 410-420 ◽  
Author(s):  
Marek-Jerzy Pindera ◽  
Zafer Gurdal ◽  
Carl T. Herakovich ◽  
Jeffrey S. Hidde ◽  
J. Michael Starbuck

2013 ◽  
Vol 376 ◽  
pp. 103-107
Author(s):  
A. Mostafa ◽  
K. Shankar

The present study deals with the shear behavior of the composite sandwich panels comprised of Polyvinylchloride (PVC) and Polyurethane (PU) foam core sandwiched between Glass Fiber Reinforced Polymer (GFRP) skins using epoxy resin. Experiments have been carried out to characterize the mechanical response of the constituent materials under tension, compression and shear loading. In-plane shear tests for the sandwich panel reveal that the main failure mode is the delamination between the skin and the core rather than shearing the core itself since the skin-core interaction is the weakest link in such structure. The Finite Element Analysis (FEA) of the sandwich structure, based on the non-linear behavior of the foam core and skin-core cohesive interaction, shows that shear response and failure mode can be predicted with high accuracy.


2013 ◽  
Vol 376 ◽  
pp. 69-73
Author(s):  
A. Mostafa ◽  
K. Shankar

The present study deals with the shear behavior of the composite sandwich panels comprised of Polyvinylchloride (PVC) and Polyurethane (PU) foam core sandwiched between Glass Fiber Reinforced Polymer (GFRP) skins using epoxy resin. Experiments have been carried out to characterize the mechanical response of the constituent materials under tension, compression and shear loading. In-plane shear tests for the sandwich panel reveal that the main failure mode is the delamination between the skin and the core rather than shearing the core itself since the skin-core interaction is the weakest link in such structure. The Finite Element Analysis (FEA) of the sandwich structure, based on the non-linear behavior of the foam core and skin-core cohesive interaction, shows that shear response and failure mode can be predicted with high accuracy.


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