Mechanical Behavior of Non Sintered and Sintered Steel Wool

2008 ◽  
Vol 47-50 ◽  
pp. 121-124 ◽  
Author(s):  
Jean Philippe Masse ◽  
K. Beyer ◽  
Didier Bouvard ◽  
Olivier Bouaziz ◽  
Yves Bréchet ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Initial Density ◽  
Cellular Materials ◽  
Compression Stress ◽  
Mechanical Compression ◽  
Compression Tests ◽  
Sintered Steel ◽  
Steel Wool ◽  
Two Temperatures

Entangled materials are similar to cellular materials, with regard to their low density and discrete architecture. In this work steel wool (sintered in a furnace for various time at two temperatures) and non sintered steel wool are investigated. Experimental mechanical compression tests were performed on both materials. Compression stress and Young’s modulus are extracted and compared with the time and temperature of sintering, and initial density. The results are analyzed using a classical Toll’s model. A special attention is paid to the value of the exponent which relates stress and Young’s modulus to density. This exponent ranges from 3 to 5 for non sintered wool, and is close to 3 for the stress law and 4 for the Young’s modulus law for sintered wool.

Compression properties of vascular boundles and parenchyma of rattan (Plectocomia assamica Griff)

Holzforschung ◽  
2014 ◽  
Vol 68 (8) ◽  
pp. 927-932 ◽  
Author(s):  
Xing’e Liu ◽  
Genlin Tian ◽  
Lili Shang ◽  
Shumin Yang ◽  
Zehui Jiang
Keyword(s):  
Young’S Modulus ◽  
Cross Section ◽  
Compression Strength ◽  
Young's Modulus ◽  
Vascular Bundles ◽  
Mechanical Compression ◽  
Compression Tests ◽  
Compression Properties ◽  
Parenchyma Cells ◽  
Different Parts

Abstract Rattan is a unique unidirectional vascular bundles-reinforced biocomposite with many nodes along its canes. Mechanical compression tests have been performed from rattan samples taken from different parts of the cross section. Compression strength increased with increasing amounts of vascular bundles (VBs) in the tissues was investigated. Samples including the outer ring with many VBs have the highest apparent Young’s modulus of 1.08 GPa and the highest compression strength of 17.6 MPa. However, samples consisting of parenchyma cells had an apparent Young’s modulus of 25 MPa, and the compression strength of 1.81 MPa. The compression properties of core samples improved with increasing amounts of VB. The apparent Young’s modulus and compression strength of a single VB were 730 MPa and 6.87 MPa, respectively, and were calculated according to the rule of mixture of composites.

Fabrication and Testing of Planar Stent Mesh Designs Using Carbon-Infiltrated Carbon Nanotubes

2013 ◽  
Vol 4 (2) ◽  
Author(s):  
Kristopher Jones ◽  
Brian D. Jensen ◽  
Anton Bowden
Keyword(s):  
Carbon Nanotubes ◽  
Young’S Modulus ◽  
Fracture Strain ◽  
Young's Modulus ◽  
Chemical Vapor ◽  
Pyrolytic Carbon ◽  
Compression Tests ◽  
Element Analysis ◽  
Percent Elongation ◽  
Fea Model

This paper explores and demonstrates the potential of using pyrolytic carbon as a material for coronary stents. Stents are commonly fabricated from metal, which has worse biocompatibilty than many polymers and ceramics. Pyrolytic carbon, a ceramic, is currently used in medical implant devices due to its preferable biocompatibility properties. Micropatterned pyrolytic carbon implants can be created by growing carbon nanotubes (CNTs), and then filling the space between with amorphous carbon via chemical vapor deposition (CVD). We prepared multiple samples of two different stent-like flexible mesh designs and smaller cubic structures out of carbon-infiltrated carbon nanotubes (CI-CNT). Tension loads were applied to expand the mesh samples and we recorded the forces at brittle failure. The cubic structures were used for separate compression tests. These data were then used in conjunction with a nonlinear finite element analysis (FEA) model of the stent geometry to determine Young's modulus and maximum fracture strain in tension and compression for each sample. Additionally, images were recorded of the mesh samples before, during, and at failure. These images were used to measure an overall percent elongation for each sample. The highest fracture strain observed was 1.4% and Young's modulus values confirmed that the material was similar to that used in previous carbon-infiltrated carbon nanotube work. The average percent elongation was 86% with a maximum of 145%. This exceeds a typical target of 66%. The material properties found from compression testing show less stiffness than the mesh samples; however, specimen evaluation reveals poorly infiltrated samples.

The Influence of the Bauschinger Effect on the Yield Stress, Young’s Modulus, and Poisson’s Ratio of a Gun Barrel Steel

2005 ◽  
Vol 128 (2) ◽  
pp. 179-184 ◽  
Author(s):  
J. Perry ◽  
M. Perl ◽  
R. Shneck ◽  
S. Haroush
Keyword(s):  
Plastic Deformation ◽  
Yield Stress ◽  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Bauschinger Effect ◽  
Young's Modulus ◽  
Poisson's Ratio ◽  
Compression Tests ◽  
Residual Stress Field ◽  
Gun Barrel

The Bauschinger effect (BE) was originally defined as the phenomenon whereby plastic deformation causes a loss of yield strength restraining in the opposite direction. The Bauschinger effect factor (BEF), defined as the ratio of the yield stress on reverse loading to the initial yield stress, is a measure of the magnitude of the BE. The aim of the present work is to quantitatively evaluate the influence of plastic deformation on other material properties such as Young’s modulus and Poisson’s ratio for gun barrel steel, thus extending the definition of the Bauschinger effect. In order to investigate the change in this material’s properties resulting from plastic deformation, several uniaxial tension and compression tests were performed. The yield stress and Young’s modulus were found to be strongly affected by plastic strain, while Poisson’s ratio was not affected at all. An additional result of these tests is an exact zero offset yield point definition enabling a simple evaluation of the BEF. A simple, triphase test sufficient to characterize the entire elastoplastic behavior is suggested. The obtained experimental information is readily useful for autofrettage residual stress field calculations.

Influence of Experimental Protocols on the Mechanical Properties of the Intervertebral Disc in Unconfined Compression

2011 ◽  
Vol 133 (7) ◽  
Author(s):  
Maximilien Recuerda ◽  
Simon-Pierre Coté ◽  
Isabelle Villemure ◽  
Delphine Périé
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Nucleus Pulposus ◽  
Annulus Fibrosus ◽  
Young's Modulus ◽  
Viscoelastic Model ◽  
Compression Tests ◽  
Unconfined Compression ◽  
Experimental Conditions ◽  
Experimental Protocols

The lack of standardization in experimental protocols for unconfined compression tests of intervertebral discs (IVD) tissues is a major issue in the quantification of their mechanical properties. Our hypothesis is that the experimental protocols influence the mechanical properties of both annulus fibrosus and nucleus pulposus. IVD extracted from bovine tails were tested in unconfined compression stress-relaxation experiments according to six different protocols, where for each protocol, the initial swelling of the samples and the applied preload were different. The Young’s modulus was calculated from a viscoelastic model, and the permeability from a linear biphasic poroviscoelastic model. Important differences were observed in the prediction of the mechanical properties of the IVD according to the initial experimental conditions, in agreement with our hypothesis. The protocol including an initial swelling, a 5% strain preload, and a 5% strain ramp is the most relevant protocol to test the annulus fibrosus in unconfined compression, and provides a permeability of 5.0 ± 4.2e−14m4/N·s and a Young’s modulus of 7.6 ± 4.7 kPa. The protocol with semi confined swelling and a 5% strain ramp is the most relevant protocol for the nucleus pulposus and provides a permeability of 10.7 ± 3.1 e−14m4/N·s and a Young’s modulus of 6.0 ± 2.5 kPa.

scholarly journals Influence of Degradation Products on the Elastic Stiffness Properties of Porous Absorbable Scaffolds Made From Bioabsorbable Metals

2021 ◽  
Author(s):  
Jannik Bühring ◽  
Maximilian Voshage ◽  
Johannes Heinrich Schleifenbaum ◽  
Holger Jahr ◽  
Kai-Uwe Schröder
Keyword(s):  
Finite Element ◽  
Young’S Modulus ◽  
Degradation Products ◽  
Young's Modulus ◽  
Element Model ◽  
Elastic Stiffness ◽  
Porous Scaffolds ◽  
Compression Tests ◽  
Substrate Layer ◽  
Stiffness Properties

For orthopaedic applications, additive manufactured (AM) porous scaffolds made of absorbable metals like magnesium, zinc or iron are of particular interest. They do not only offer the potential to design and fabricate bio-mimetic or rather bone equivalent mechanical properties, they also do not need to be removed in further surgery. Located in a physiological environment, scaffolds made of absorbable metals show a decreasing Young’s modulus over time, due to product dissolution. For WE43 scaffolds, during the first days an increase of the smeared Young's modulus can be observed, which is mainly attributed to a forming substrate layer of degradation products on the struts surfaces. In this study the influence of degradation products on the stiffness properties of metallic scaffolds is investigated. For this, analytical calculations and finite element simulations are performed to study the influence of the substrate layer thickness and Young's modulus for single struts and for a new scaffold geometry with adapted polar f2cc,z unit cells. The finite element model is further validated by compression tests on AM scaffolds made from Zn1Mg. The results show, that even low thicknesses and Young's moduli of the substrate layer increases significantly the smeared Young's modulus under axial compression.

scholarly journals Influence of Degradation Product Thickness on the Elastic Stiffness of Porous Absorbable Scaffolds Made from an Bioabsorbable Zn–Mg Alloy

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6027
Author(s):  
Jannik Bühring ◽  
Maximilian Voshage ◽  
Johannes Henrich Schleifenbaum ◽  
Holger Jahr ◽  
Kai-Uwe Schröder
Keyword(s):  
Finite Element ◽  
Young’S Modulus ◽  
Degradation Products ◽  
Young's Modulus ◽  
Element Model ◽  
Elastic Stiffness ◽  
Porous Scaffolds ◽  
Compression Tests ◽  
Young’S Moduli ◽  
Substrate Layer

For orthopaedic applications, additive manufactured (AM) porous scaffolds made of absorbable metals such as magnesium, zinc or iron are of particular interest. They do not only offer the potential to design and fabricate bio-mimetic or rather bone-equivalent mechanical properties, they also do not need to be removed in further surgery. Located in a physiological environment, scaffolds made of absorbable metals show a decreasing Young’s modulus over time, due to product dissolution. For magnesium-based scaffolds during the first days an increase of the smeared Young’s modulus can be observed, which is mainly attributed to a forming substrate layer of degradation products on the strut surfaces. In this study, the influence of degradation products on the stiffness properties of metallic scaffolds is investigated. For this, analytical calculations and finite-element simulations are performed to study the influence of the substrate layer thickness and Young’s modulus for single struts and for a new scaffold geometry with adapted polar cubic face-centered unit cells with vertical struts (f2cc,z). The finite-element model is further validated by compression tests on AM scaffolds made from Zn1Mg (1 wt% Mg). The results show that even low thicknesses and Young’s moduli of the substrate layer significantly increases the smeared Young’s modulus under axial compression.

Sign in / Sign up

Export Citation Format

Share Document