Compressive Tests (compressive + test)

Distribution by Scientific Domains


Selected Abstracts


Novel Nanostructure and Deformation Behavior in Rapidly Quenched Cu- (Zr or Hf)-Ti Alloys,

ADVANCED ENGINEERING MATERIALS, Issue 1-2 2005
J. Saida
Novel nanostructure consisting of the metastable nanocrystalline particles embedded in the glassy matrix are reported in the rapidly quenched Cu60(Zr or Hf)30Ti10 alloys. The transformation behavior and mechanical properties in the nanoscale composite alloys are also investigated. The as-cast bulk sample of Cu60Zr30Ti10 alloy exhibits the high fracture strength of approximately 2000 MPa in the compressive test at room temperature. [source]


A numerical method for the study of shear band propagation in soft rocks

INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 13 2009
Marta Castelli
Abstract This paper investigates the possibility of interpreting progressive shear failure in hard soils and soft rocks as the result of shear propagation of a pre-existing natural defect. This is done through the application of the principles of fracture mechanics, a slip-weakening model (SWM) being used to simulate the non-linear zone at the tips of the discontinuity. A numerical implementation of the SWM in a computation method based on the boundary element technique of the displacement discontinuity method (DDM) is presented. The crack and the non-linear zone at the advancing tip are represented through a set of elements, where the displacement discontinuity (DD) in the tangential direction is determined on the basis of a friction law. A residual friction angle is assumed on the crack elements. Shear resistance decreases on elements in the non-linear zone from a peak value at the tip, which is characteristic of intact material, to the residual value. The simulation of a uniaxial compressive test in plane strain conditions is carried out to exemplify the numerical methodology. The results emphasize the role played by the critical DD on the mechanical behaviour of the specimen. A validation of the model is shown through the back analysis of some experimental observations. The results of this back analysis show that a non-linear fracture mechanics approach seems very promising to simulate experimental results, in particular with regards to the shear band evolution pattern. Copyright © 2009 John Wiley & Sons, Ltd. [source]


Aluminum "Egg-Box" Panel as an Energy Absorber for Pedestrian Protection

ADVANCED ENGINEERING MATERIALS, Issue 7 2010
Sravanthi Nowpada
Abstract This paper evaluates the quasi-static performance of lightweight aluminum "egg-box" panels which have an improved architecture specifically designed to increase the energy absorption capability. In its entirety, the egg-box panel structure investigated herein is made up of arrays of positive and negative frusta. To understand the collapse mechanism and the factors influencing the energy absorption thereof, compressive tests were conducted under similar test conditions on two single frusta, one constrained in situ and the other separated from the egg-box panel exposing the free,free edges. Their load-displacement histories show characteristics that are similar, with a rise in load to a point where they plateau at a steady state load for the entire collapse time. But the energy absorbed by the in situ constrained frustum is 80% greater than that separated from the egg-box panel with free,free edges. [source]


Enhanced Ductility of Dendrite-Ultrafine Eutectic Composite Fe3B Alloy Prepared by a Self-Propagating High-Temperature Synthesis,

ADVANCED ENGINEERING MATERIALS, Issue 3 2009
Licai Fu
The bulk dendrite-ultrafine eutectic composite Fe3B alloy was prepared by a self-propagating high-temperature synthesis. This technique is convenient, low cost, and capable of being scaled up for processing bulk nano/ultrafine-structured materials. The Fe3B alloy is composed of a micrometer-sized dendrite dispersed in an ultrafine laminar eutectic matrix and exhibits both high strength and large ductility in compressive tests. [source]


Effect of suction on the mechanical behaviour of iron ore rock

INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 8 2005
Dragan Grgic
Abstract The effect of suction on the behaviour of iron ore has been studied from both physical and mechanical points of view. The porosity and the suction phenomena have been analysed using different experimental techniques. Uniaxial compressive tests on partially saturated samples have shown that the suction is responsible for strength and cohesion improvement. Considering the theory of partially saturated porous soils of Coussy and Dangla (Mécanique des sols non saturés (2002 edn). Hermès Science: 2002; 390), we have proposed a constitutive law for partially saturated iron ore. The real increase in the apparent cohesion due to the capillary attraction forces is overestimated if the yield function is written in terms of effective stresses. The effect of the capillary cohesion has been modelled with a function in the expression of the apparent cohesion of the yield function. The effect of suction on the mechanical behaviour has been represented in the effective stresses space and in the total stresses space like the Alonso model (Géotechnique 1990; 40:405,430). Copyright © 2005 John Wiley & Sons, Ltd. [source]


Chemical characteristics and cytocompatibility of collagen-based scaffold reinforced by chitin fibers for bone tissue engineering

JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2006
Xiaoming Li
Abstract Chitin is a kind of seemly material to match PLLA for a scaffold, which may create an appropriate environment for the regeneration of tissues. In this study, we prepared and evaluated a new nano-hydroxyapatite/collagen/PLLA (nHACP) scaffold reinforced by chitin fibers for bone-tissue engineering. The chitin fibers were crosslinked with PLLA by dicyclohexylcarbodimide (DCC). The chemical characteristics were evaluated by Fourier transformed infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The mechanical strength was measured by compressive tests. The fibers, crosslinked with PLLA, could enhance the compressive strength of the scaffold about four times. Human marrow mesenchymal stem cells (MSCs) culture showed that the reinforced nHACP scaffolds were more cytocompatible than that without reinforcement. The crosslinks hardly affected the cytocompatibility of the reinforced scaffolds. The results suggested that the reinforced scaffolds (DCC crosslinked) might be a promising candidate for bone-tissue engineering. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006 [source]


Auxetic compliant flexible PU foams: static and dynamic properties

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 3 2005
F. Scarpa
Abstract The paper describes the manufacturing and tensile testing of auxetic (negative Poisson's ratio) thermoplastic polyurethane foams, both under constant strain rate and sinusoidal excitation. The foams are produced from conventional flexible polyurethane basis following a manufacturing route developed in previous works. The Poisson's ratio behaviour over tensile strain has been analyzed using an Image Data processing technique based on Edge Detection from digital images recorded during quasi-static tensile test. The samples have been subjected to tensile and compressive tests at quasi-static and constant strain-rate values (up to 12 s,1). Analogous tests have been performed over iso-volumetric foams samples, i.e., foams subjected to the same volumetric compression of the auxetic ones, exhibiting a near zero Poisson's ratio behaviour. The auxetic and non-auxetic foams have been also tested under sinusoidal cycling load up to 10 Hz, with maximum pre-strain applied of 12%. The hysteresis of the cycling loading curve has been measured to determine the damping hysteretic loss factor for the various foams. The measurements indicate that auxetic foams have increased damping loss factor of 20% compared to the conventional foams. The energy dissipation is particularly relevant in the tensile segment of the curve, with effects given by the pre-strain level imposed on the samples. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]