Mechanical Properties of Tendons: Changes With Sterilization and Preservation

1996 ◽  
Vol 118 (1) ◽  
pp. 56-61 ◽  
Author(s):  
C. W. Smith ◽  
I. S. Young ◽  
J. N. Kearney
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Freeze Drying ◽  
Dynamic Testing ◽  
Young's Modulus ◽  
Testing Machine ◽  
Ultimate Tensile Stress ◽  
Tissue Banks ◽  
Freeze Dried ◽  
Significant Difference

Tendon allografts are commonly used to replace damaged anterior cruciate ligaments (ACL). Some of the sterilization and preservation techniques used by tissue banks with tendon allografts are thought to impair the mechanical properties of graft tissues. The tensile mechanical properties of porcine toe extensor tendons were measured using a dynamic testing machine following either freezing, freeze-drying, freezing then irradiation at 25 kGy (2.5 MRad), freeze-drying then irradiation, or freeze-drying then ethylene oxide gas sterilization. There was a small but significant difference in Young’s modulus between the frozen group (0.88 GPa ± 0.09 SD) and both the fresh group (0.98 GPa ± 0.12 SD) and the frozen irradiated group (0.97 GPa ± 0.08 SD). No values of Young’s modulus were obtained for the freeze-dried irradiated tendons. The ultimate tensile stress (UTS) of the freeze-dried irradiated group (4.7 MPa ± 4.8 SD) was significantly different from both the fresh and the frozen irradiated groups, being reduced by approximately 90 percent. There were no significant changes in UTS or Young’s modulus between any of the other groups. If irradiation is to be used to sterilize a tendon replacement for an ACL it must take place after freeze-drying to maintain mechanical properties.

An Experimental Study of Carbon Nanotube Reinforcements

2011 ◽  
Author(s):  
Lauren Patrin ◽  
Frank Chow ◽  
Gabriela Philippart ◽  
Feridun Delale ◽  
Benjamin Liaw ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Young's Modulus ◽  
Testing Machine ◽  
Type I ◽  
Electrical Measurements ◽  
Standard Type ◽  
Reinforcement Percentage

Due to their high strength and stiffness carbon nanotubes (CNTs) have been considered as candidates for reinforcement of polymeric resins. It is also known that the addition of CNTs to polymeric matrix results in highly conductive nanocomposites, making the material multifunctional. Most of the CNT reinforced polymeric nanocomposite systems reported in the literature have been studied at room temperature. However, in many applications, materials may be subjected from low to elevated temperatures. Thus, the aim of this research is to study CNT reinforced polypropylene (PP) specimens at room, elevated and low temperatures. ASTM standard Type I specimens manufactured via injection molding and reinforced with 0.2%, 1%, 3%, and 6% CNTs were first subjected to tensile loads in a universal testing machine at room temperature. Neat PP resin specimens were also tested to provide baseline data. The tests were repeated at −54°C (−65°F), −20°C (−4°F), 49°C (120°F) and 71°C (160°F). The results were plotted as stress-strain curves and analyzed to delineate the effect of CNT reinforcement percentage and temperature on the mechanical properties. It was noted that as the percentage of CNT reinforcement increases, the resulting nanocomposite becomes stiffer (higher Young’s modulus), has higher strength and becomes more brittle. Temperature has a drastic effect on the behavior of the nanocomposite. As the temperature increases, at a given reinforcement percentage the material becomes more ductile with significantly lower Young’s modulus and strength compared to room temperature. At lower temperatures, the nanocomposite becomes more brittle with higher stiffness and strength, but significantly reduced failure strain. Also electrical measurements were conducted on the specimens to measure their resistance. For specimens reinforced with up to 3% of CNTs no electrical conductivity was detected. As expected at 6% CNT reinforcement (which is above the approximately 4% percolation limit reported in the literature), the specimens became electrically conductive. To predict the mechanical properties obtained experimentally, a micromechanics based model is presented and compared with the experimental results.

Comparison of Microstructure and Mechanical Properties of Aluminum Components Manufactured by CMT

2017 ◽  
Vol 898 ◽  
pp. 1318-1324 ◽  
Author(s):  
Y. Zhao ◽  
Jian Xiao ◽  
S.J. Chen
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Ultrasonic Method ◽  
Fusion Line ◽  
Al Alloy ◽  
Continuous Growth ◽  
Line Region ◽  
Significant Difference

This paper presents an investigation on the microstructure and mechanical property of Al-alloy parts made by using additive manufacturing based on CMT (Cold Metal Transfer) welding technology. With the same 3D model and process parameters, a set of hollow cylindrical parts with 100 layers were built up using 2319, 4043, 5356 aluminum welding wires, respectively. Then their microstructure, tensile strength, and microhardness were tested and analyzed comparatively. The layer bands characteristics were obviously observed in both 2319 and 4043 parts. In the interlayer region of the 2319 parts, the segregation of alloying elements on the grain boundaries and inside the grains were significantly more than that in the fusion line region. For the microstructure of 4043 parts, the dendrites grow upward from the bottom without interruption in the fusion line region, and the continuous growth structure was maintained. There is no obviously change on the microhardness from the bottom to the top because the organization is uniform and there is no significant difference in the grain size. The ultimate strength and elongation in the horizontal direction were higher than those in the longitudinal direction, and the 5356 parts had best mechanical properties among the three materials. Ultrasonic method was also used to measure the Young's modulus of the additive manufactured parts. The Young's modulus measuring results were accordant with the results obtained by the mechanical property testing, and the error was within 3%.

MECHANICAL PROPERTIES OF CHORDAE TENDINEAE OF THE MITRAL HEART VALVE: YOUNG'S MODULUS, STRUCTURAL STIFFNESS, AND EFFECTS OF AGING

2011 ◽  
Vol 11 (01) ◽  
pp. 221-230 ◽  
Author(s):  
LAURA MILLARD ◽  
DANIEL M. ESPINO ◽  
DUNCAN E. T. SHEPHERD ◽  
DAVID W. L. HUKINS ◽  
KEITH G. BUCHAN
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Finite Element Models ◽  
Structural Stiffness ◽  
Posterior Leaflet ◽  
Chordae Tendineae ◽  
Significant Difference ◽  
Valve Function ◽  
Effects Of Aging

Young's modulus and structural stiffness were determined for chordae tendineae of the mitral valve from young (18–26 weeks) and old (over 2 years) porcine hearts. For chordae from the posterior leaflet of the valve, the Young's modulus values were significantly higher (p < 0.05) for the thinner marginal chordae (59 ± 31 MPa young; 88 ± 21 MPa old) than for the thicker basal chordae (31 ± 4 MPa young; 28 ± 9 MPa old). Marginal chordae (both anterior and posterior) had significantly higher (p < 0.05) value for their Young's modulus in old (88 ± 21 MPa anterior and posterior) than in young (62 ± 17 MPa anterior, 59 ± 18 MPa posterior) pig hearts. There was no significant difference in structural stiffness between marginal and basal (anterior and posterior leaflets) or between strut chordae (that are associated with anterior the leaflet only) and marginal and basal chordae. However, the value of structural stiffness of chordae was significantly higher (p < 0.05) for old (2.2 ± 0.2 kN/m) than for young (2.0 ± 0.4 kN/m) chordae. These results show that aging affects the properties of chordae and that all chordae need to be included in finite element models of valve function.

Mechanical Properties of Carboxymethyl Cellulose-Oleic Acid Solid Biopolymer Electrolyte

2018 ◽  
Vol 929 ◽  
pp. 186-190 ◽  
Author(s):  
M.N. Chai ◽  
M.M. Chai ◽  
M.I.N. Isa
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Oleic Acid ◽  
Young’S Modulus ◽  
Carboxymethyl Cellulose ◽  
Young's Modulus ◽  
Testing Machine ◽  
Strain Curve ◽  
Weight Percentage ◽  
Universal Material Testing Machine

In this paper, the mechanical properties of carboxymethyl cellulose-oleic acid (CMC-OA) solid bio-polymer electrolyte (SBE) were examined. The host, CMC was doped with different weight percentage (wt. %) of OA in the CMC-OA solution. The SBEs were tested by using the Universal Material Testing Machine where the readings of tensile strength and Young’s modulus can be obtained from the stress-strain curve produced by the software during the tension test. The sample of CMC doped with 20% wt. of OA was found to obtain the highest value of tensile strength and Young’s modulus which is 0.2069 MPa and 4.615 MPa respectively.

Recycled HDPE-tetrapack composites. Isothermal crystallization, light scattering and mechanical properties

2012 ◽  
Vol 1485 ◽  
pp. 77-82 ◽  
Author(s):  
A Parada-Soria ◽  
HF Yao ◽  
B Alvarado-Tenorio ◽  
L Sanchez-Cadena ◽  
A Romo-Uribe
Keyword(s):  
Mechanical Properties ◽  
Light Scattering ◽  
Young’S Modulus ◽  
Tensile Deformation ◽  
Young's Modulus ◽  
Ultimate Tensile Stress ◽  
Uniaxial Tensile ◽  
Scanning Calorimetry ◽  
Slow Cooling ◽  
The Matrix

ABSTRACTIn this research the thermal and mechanical properties of composites based on recycled high-density polyethylene (HDPE) and recycled Tetrapak have been investigated. The matrix and filler are recovered from landfills. Multicolor HDPE mixtures, with varying concentration of tetrapack flakes, are hot pressed, as well as single color HDPE flakes. Previous studies determine that the nature of the pigment (organics vs. inorganics) strongly influence the mechanical behavior of multicolor HDPE-tetrapack composites. Thus, this research focuses on single color HDPE hot pressed plaques. The kinetics of crystallization under isothermal conditions is determined by differential scanning calorimetry (DSC). The results show that the crystallization kinetics obeys the Avrami theory, and that the Avrami exponent is 1, irrespective of the pigment in use. Small-angle light scattering is applied to investigate the internal structure of the pigmented HDPE. SALS patterns show that the samples exhibited oriented morphologies. However, after melting and slow cooling under pressure the samples exhibit an isotropic morphology. This is confirmed by polarized optical microscopy. Mechanical properties such as Young’s modulus, yield stress and ultimate tensile stress are obtained under uniaxial tensile deformation at room temperature. For the single color HDPE plaques the Young’s modulus is reduced (after melting), suggesting that the anisotropic molecular chains contribute to the higher value of Young’s modulus.

scholarly journals Morphology and Mechanical Properties of Plantar Fascia in Flexible Flatfoot: A Noninvasive In Vivo Study

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhihui Qian ◽  
Zhende Jiang ◽  
Jianan Wu ◽  
Fei Chang ◽  
Jing Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Plantar Fascia ◽  
The Other ◽  
Flexible Flatfoot ◽  
Significant Difference ◽  
Peak Pressures ◽  
Morphology And Mechanical Properties

Plantar fascia plays an important role in human foot biomechanics; however, the morphology and mechanical properties of plantar fascia in patients with flexible flatfoot are unknown. In this study, 15 flexible flatfeet were studied, each plantar fascia was divided into 12 positions, and the morphologies and mechanical properties in the 12 positions were measured in vivo with B-mode ultrasound and shear wave elastography (SWE). Peak pressures under the first to fifth metatarsal heads (MH) were measured with FreeStep. Statistical analysis included 95% confidence interval, intragroup correlation coefficient (ICC1,1), one-way analysis of variance (one-way ANOVA), and least significant difference. The results showed that thickness and Young’s modulus of plantar fascia were the largest at the proximal fascia (PF) and decreased gradually from the proximal end to the distal end. Among the five distal branches (DB) of the fascia, the thickness and Young’s modulus of the second and third DB were larger. The peak pressures were also higher under the second and third MH. This study found a gradient distribution in that the thickness and Young’s modulus gradient decreased from the proximal end to the distal end of plantar fascia in the longitudinal arch of flexible flatfeet. In the transverse arch, the thickness and Young’s modulus under the second and third DB were larger than those under the other three DB in flexible flatfoot, and the peak pressures under the second and third MH were also larger than those under the other three MH in patients with flexible flatfoot. These findings deepen our understanding of the changes of biomechanical properties and may be meaningful for the study of pathological mechanisms and therapy for flexible flatfoot.

Structure and Mechanical Properties of Water Buffalo Horns

2015 ◽  
Vol 804 ◽  
pp. 247-250 ◽  
Author(s):  
Panta Surakamhang ◽  
Chontira Sangsubun
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Vickers Hardness ◽  
Water Buffalo ◽  
Young's Modulus ◽  
Testing Machine ◽  
Elongation At Break ◽  
Synthetic Materials ◽  
Southern Thailand ◽  
The Relationship

Many studies have been reported in the field of biological materials. For the most part, this interest has focused on teeth, bones, hooves and horns, elucidating the relationship between structure and mechanical properties. Due to their novel outstanding structures and mechanical properties, this knowledge is helpful for the use and design of the superior bio-inspired synthetic materials. Similarly, this research aims to investigate the microstructure and mechanical properties of the water buffalo horn in 1-5 years old in Phatthalung province in southern Thailand. The tensile properties and the Young’s modulus were systematically measured by a universal testing machine. The hardness was determined by micro vickers hardness testing machines. The results showed that the average of Young’s modulus, the tensile strength at break and the vickers hardness of a 2-year-old water buffalo horn were about 6.1 GPa, 92.6 MPa and 180 MPa, respectively, which were higher than that at 1, 3, 4 and 5 years old. The elongation at break of a 1 year old water buffalo horn has a maximum value of 61%. The microstructure and chemical composition were investigated using scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDX), respectively. The results of SEM showed that the fracture surface of the water buffalo horn has a rippled shape in each layer. The EDX analysis showed that the water buffalo horn consists of carbon, nitrogen, sulfur and oxygen.

The Effects of Trabecular Bone Microstructure on Compression Property of Bovine Cancellous Bone

2010 ◽  
Vol 452-453 ◽  
pp. 297-300
Author(s):  
Kazuto Tanaka ◽  
Yusuke Tanimoto ◽  
Yusuke Kita ◽  
Shinichi Enoki ◽  
Tsutao Katayama
Keyword(s):  
Mechanical Properties ◽  
Bone Density ◽  
Trabecular Bone ◽  
Young’S Modulus ◽  
Ultimate Strength ◽  
Cancellous Bone ◽  
Young's Modulus ◽  
Testing Machine ◽  
Bone Microstructure ◽  
Trabecular Bone Microstructure

To establish clinical bone assessment for osteoporosis, it is necessary to evaluate not only bone density but also trabecular bone microstructure and mechanical properties of bone. Therefore relationship between the micro-structural parameters and the mechanical properties of the cancellous bone of bovine distal femur was investigated. Compression test was carried out using universal testing machine to measure Young’s modulus and the ultimate strength. X-ray CT was used to obtain 3D image of specimens. Bone trabecular orientation was obtained from fabric ellipse by the MIL (Mean Intercept Length) analysis. Young’s modulus and ultimate strength had a high correlation with bone density respectively; furthermore ultimate strength had a high correlation with Young’s modulus.

Mechanical properties of FeAlSi powders prepared by mechanical alloying from different initial feedstock materials

2019 ◽  
Vol 107 (2) ◽  
pp. 207 ◽  
Author(s):  
Jaroslav Čech ◽  
Petr Haušild ◽  
Miroslav Karlík ◽  
Veronika Kadlecová ◽  
Jiří Čapek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Alloying ◽  
Young’S Modulus ◽  
Milling Time ◽  
Young's Modulus ◽  
Element Model ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Particles ◽  
Complete Homogenization

FeAl20Si20 (wt.%) powders prepared by mechanical alloying from different initial feedstock materials (Fe, Al, Si, FeAl27) were investigated in this study. Scanning electron microscopy, X-ray diffraction and nanoindentation techniques were used to analyze microstructure, phase composition and mechanical properties (hardness and Young’s modulus). Finite element model was developed to account for the decrease in measured values of mechanical properties of powder particles with increasing penetration depth caused by surrounding soft resin used for embedding powder particles. Progressive homogenization of the powders’ microstructure and an increase of hardness and Young’s modulus with milling time were observed and the time for complete homogenization was estimated.

scholarly journals First principles computation of composition dependent elastic constants of omega in titanium alloys: implications on mechanical behavior

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. Salloom ◽  
S. A. Mantri ◽  
R. Banerjee ◽  
S. G. Srinivasan
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
First Principles ◽  
Young's Modulus ◽  
Group Vi ◽  
Group V ◽  
Β Phase ◽  
Ti Alloys ◽  
Ω Phase ◽  
Stabilizer Concentration

AbstractFor decades the poor mechanical properties of Ti alloys were attributed to the intrinsic brittleness of the hexagonal ω-phase that has fewer than 5-independent slip systems. We contradict this conventional wisdom by coupling first-principles and cluster expansion calculations with experiments. We show that the elastic properties of the ω-phase can be systematically varied as a function of its composition to enhance both the ductility and strength of the Ti-alloy. Studies with five prototypical β-stabilizer solutes (Nb, Ta, V, Mo, and W) show that increasing β-stabilizer concentration destabilizes the ω-phase, in agreement with experiments. The Young’s modulus of ω-phase also decreased at larger concentration of β-stabilizers. Within the region of ω-phase stability, addition of Nb, Ta, and V (Group-V elements) decreased Young’s modulus more steeply compared to Mo and W (Group-VI elements) additions. The higher values of Young’s modulus of Ti–W and Ti–Mo binaries is related to the stronger stabilization of ω-phase due to the higher number of valence electrons. Density of states (DOS) calculations also revealed a stronger covalent bonding in the ω-phase compared to a metallic bonding in β-phase, and indicate that alloying is a promising route to enhance the ω-phase’s ductility. Overall, the mechanical properties of ω-phase predicted by our calculations agree well with the available experiments. Importantly, our study reveals that ω precipitates are not intrinsically embrittling and detrimental, and that we can create Ti-alloys with both good ductility and strength by tailoring ω precipitates' composition instead of completely eliminating them.

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