Effect of Anatomical Sites On the Mechanical Properties of Spinal Dura Subjected to Biaxial Stretching

2021 ◽  
Author(s):  
Atsutaka Tamura ◽  
Soichiro Nishikawa
Keyword(s):  
Mechanical Properties ◽  
Dura Mater ◽  
Longitudinal Direction ◽  
Ventral Side ◽  
Dorsal Side ◽  
Tensile Tester ◽  
Material Stiffness ◽  
Cerebrospinal Fluid Leaks ◽  
Physiological Motion

Abstract The spinal cord is encased by spinal meninges called the pia, arachnoid, and dura maters. Among these membranes, the dura mater is the thick and outermost layer and is the toughest and strongest. Thus, mechanical failure of the dura mater can lead to spontaneous cerebrospinal fluid leaks or hypovolemia, resulting in a complication or exacerbation of unfavorable symptoms involved in a mild traumatic brain injury. To develop protective equipment that can help prevent such injuries, accurate characterization of the spinal dura mater is required, especially regarding the mechanical properties at different anatomical sites. In this study, we used an equiload biaxial tensile tester to investigate the mechanical properties of porcine meningeal dura mater along the whole length of the spine. The resultant strain of the dorsal side was greater than that of the ventral side (P < 0.01), while the circumferential direction was significantly stiffer than the longitudinal direction (P < 0.01) at lower strains regardless of the spinal level. We also found that the material stiffness progressively increased from the cervical level to the thoracolumbar level at lower strains, which implies that the dura mater inherently possesses structurally preferred features or functions because the neck requires sufficient flexibility for daily activities. Further, Young's modulus was significantly less on the dorsal side than on the ventral side at higher strains (P < 0.05), suggesting that the dorsal side is readily elongated by spinal flexion even within the range of physiological motion.

MECHANICAL CHARACTERIZATION OF SPINAL DURA USING A PD-CONTROLLED BIAXIAL TENSILE TESTER

2020 ◽  
Vol 20 (05) ◽  
pp. 2050023
Author(s):  
ATSUTAKA TAMURA ◽  
WATARU YANO ◽  
DAICHI YOSHIMURA ◽  
SOICHIRO NISHIKAWA
Keyword(s):  
Dura Mater ◽  
Mechanical Response ◽  
Longitudinal Direction ◽  
Mechanical Tests ◽  
Circumferential Direction ◽  
Lumbar Region ◽  
Biaxial Tensile ◽  
Tensile Tester ◽  
Significant Difference ◽  
Upper Thoracic

In this study, we developed an equi-load biaxial tensile tester and applied it to a series of mechanical tests using specimens obtained from the porcine spinal dura mater. The dural sample exhibited a nonlinear and anisotropic behavior as it was more deformable in the longitudinal direction rather than in the circumferential direction at lower strains; i.e., mechanical response of the longitudinal direction was significantly compliant in the Toe region compared to that of the circumferential direction under 1:1 biaxial stretching. However, we have not observed a significant difference with respect to the resultant strain and Young’s modulus between the longitudinal and circumferential directions at higher strains or in the Linear region. Our results also indicated that the upper thoracic region (T1) was relatively compliant compared to the lumbar region (L), where the failure load was almost equal between them because the dural thickness of T1 was five-fold greater than that of L; i.e., spinal dura mater became stiffer and stronger at further distances from the brain. This shows structural effectiveness and may be preferable to mechanically protect the vulnerable spinal cord from externally applied impact loads.

Study on Mechanical Properties for Shearing Breakage of Oat Kernel

2017 ◽  
Vol 14 (2) ◽  
Author(s):  
Nan Zhao ◽  
Nan Fu ◽  
Dong Li ◽  
Li-jun Wang ◽  
Xiao Dong Chen
Keyword(s):  
Mechanical Properties ◽  
Moisture Content ◽  
Loading Rate ◽  
Ventral Side ◽  
Dorsal Side ◽  
Breaking Force ◽  
Distance Curve ◽  
Randomized Design ◽  
Breaking Energy ◽  
Content Range

AbstractBreaking force, deformation, breaking energy, strength, hardness and rigidity of oat kernel under different loading rates (0.02, 0.04, 0.06, 0.08 and 0.10 mm/s) and loading position (ventral and dorsal sides) were determined within a moisture content range of 15.7 %–27.5 % (w.b.) by using a texture analyzer (TA) to investigate mechanical properties for shearing breakage of oat kernel. Complete randomized design was experimented to construct the force–distance curve. In this study, these mechanical properties of oat kernel were expressed as a function of moisture content and loading rate respectively. The result showed that breaking force, energy, strength, hardness and rigidity decreased linearly with the increasing moisture content and increased firstly and decreased then with the increasing loading rate. Deformation had an increasing trend with the increase in moisture content and loading rate. The highest values of breaking force, breaking energy, strength, hardness and rigidity were obtained at 0.08 mm/s loading rate. Moreover the dorsal side of oat kernel had a better shearing capacity compared with ventral side, which reflected in that breaking force, strength and hardness were great significantly at 95 % confident level when dorsal side was loaded.

scholarly journals Production and Characterization of Large-Scale Recycled Newspaper Enhanced HDPE Composite Laminates

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 851 ◽  
Author(s):  
Binwei Zheng ◽  
Litao Guan ◽  
Weiwei Zhang ◽  
Jin Gu ◽  
Dengyun Tu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Composite Laminates ◽  
Large Scale ◽  
Stress Transfer ◽  
Laminated Composite ◽  
Physical And Mechanical Properties ◽  
Longitudinal Direction ◽  
Industrial Applications ◽  
Splicing Pattern

Recycled newspaper (NP)/high density polyethylene (HDPE) laminated composite can reach the physical and mechanical criteria for most industrial applications, which shows the potential of using solid-state waste paper in engineering materials. Herein, the effects of splicing pattern and size on the physical and mechanical properties of the laminated composite were investigated with the ultimate purpose to fabricate a large-scaleale composite. The laminated composite with a stair-like splicing had better physical and mechanical properties than that with a vertical splicing. An efficient stress transfer could be guaranteed when the distance between the two adjacent junctions were greater than a critical proportion of 1/32 of the length at longitudinal direction. The tensile and flexural properties of the large-scaleale composite with a stair-like splicing, which was fabricated at the splicing ratio of 1/32, were 109 ± 4.2 MPa (MOR), 9836 ± 411 MPa (MOE), 119 ± 7.1 MPa (MOR) and 10002 MPa ± 347 (MOE).

AFM Based Nanomechanical Characterization of Cellulose Nanofibril

2020 ◽  
Vol 54 (28) ◽  
pp. 4487-4493 ◽  
Author(s):  
M Subbir Parvej ◽  
Xinnan Wang ◽  
Long Jiang
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Natural Fibers ◽  
Longitudinal Direction ◽  
Cellulose Nanofibril ◽  
Force Microscopy ◽  
Atomic Force ◽  
Main Factors ◽  
Almost All

Cellulose nanofibril (CNF) is the fundamental unit of almost all types of natural fibers and is regarded as one of the main factors that influence their mechanical properties. Besides, owing to having a high aspect ratio, it is increasingly being used in the research of nanocomposite as a reinforcement recently. In order to utilize CNF as reinforcement more effectively, it is important to have a comprehensive idea about the mechanical properties of individual CNFs. Most of the studies are focused on the elastic modulus in the longitudinal direction, but the study of the elastic modulus in the transverse direction is still lacking. In this study, a single strand of CNF was subjected to an atomic force microscopy to characterize the surface morphology of CNF and determine the transverse elastic modulus through nanoindentation. The transverse elastic modulus of CNF was calculated to be 6.9 [Formula: see text] 0.4 GPa using extended JKR model.

Microstructural and fractographic characterization of B4C-Al cermets tested under dynamic and static loading

1989 ◽  
Vol 47 ◽  
pp. 562-563
Author(s):  
Gyeung Ho Kim ◽  
Mehmet Sarikaya ◽  
D. L. Milius ◽  
I. A. Aksay
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Static Loading ◽  
Carbon Deposition ◽  
Full Density ◽  
Unique Combination ◽  
Strong Component ◽  
Reaction Products

Cermets are designed to optimize the mechanical properties of ceramics (hard and strong component) and metals (ductile and tough component) into one system. However, the processing of such systems is a problem in obtaining fully dense composite without deleterious reaction products. In the lightweight (2.65 g/cc) B4C-Al cermet, many of the processing problems have been circumvented. It is now possible to process fully dense B4C-Al cermet with tailored microstructures and achieve unique combination of mechanical properties (fracture strength of over 600 MPa and fracture toughness of 12 MPa-m1/2). In this paper, microstructure and fractography of B4C-Al cermets, tested under dynamic and static loading conditions, are described.The cermet is prepared by infiltration of Al at 1150°C into partially sintered B4C compact under vacuum to full density. Fracture surface replicas were prepared by using cellulose acetate and thin-film carbon deposition. Samples were observed with a Philips 3000 at 100 kV.

Characterization of interfaces in CVD-coated nicalon fiber-reinforced SiC

1989 ◽  
Vol 47 ◽  
pp. 556-557
Author(s):  
K.L. More ◽  
R.A. Lowden
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Frictional Stress ◽  
Fiber Reinforced ◽  
Pull Out ◽  
Carbon Coated ◽  
Fiber Matrix

The mechanical properties of fiber-reinforced composites are directly related to the nature of the fiber-matrix bond. Fracture toughness is improved when debonding, crack deflection, and fiber pull-out occur which in turn depend on a weak interfacial bond. The interfacial characteristics of fiber-reinforced ceramics can be altered by applying thin coatings to the fibers prior to composite fabrication. In a previous study, Lowden and co-workers coated Nicalon fibers (Nippon Carbon Company) with silicon and carbon prior to chemical vapor infiltration with SiC and determined the influence of interfacial frictional stress on fracture phenomena. They found that the silicon-coated Nicalon fiber-reinforced SiC had low flexure strengths and brittle fracture whereas the composites containing carbon coated fibers exhibited improved strength and fracture toughness. In this study, coatings of boron or BN were applied to Nicalon fibers via chemical vapor deposition (CVD) and the fibers were subsequently incorporated in a SiC matrix. The fiber-matrix interfaces were characterized using transmission and scanning electron microscopy (TEM and SEM). Mechanical properties were determined and compared to those obtained for uncoated Nicalon fiber-reinforced SiC.

PREPARATION AND CHARACTERIZATION OF REPROCESSED COMPOSITES OF POLYPROPYLENE REINFORCED BY WOOD FIBERS: PHYSICAL AND MECHANICAL PROPERTIES

2017 ◽  
Author(s):  
Thais Helena Sydenstricker Flores-Sahagun ◽  
Kelly Priscila Agapito ◽  
ROSA MARIA JIMENEZ AMEZCUA ◽  
Felipe Jedyn
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Wood Fibers

Emerging Techniques for the Characterization of Nano-Mechanical Properties of Integrated Circuit Components

2008 ◽  
Author(s):  
Nicholas Randall ◽  
Rahul Premachandran Nair
Keyword(s):  
Mechanical Properties ◽  
Quality Control ◽  
Integrated Circuits ◽  
Integrated Circuit ◽  
Manufacturing Process ◽  
Solder Bumps ◽  
Initial Work ◽  
Circuit Components ◽  
Materials Used

Abstract With the growing complexity of integrated circuits (IC) comes the issue of quality control during the manufacturing process. In order to avoid late realization of design flaws which could be very expensive, the characterization of the mechanical properties of the IC components needs to be carried out in a more efficient and standardized manner. The effects of changes in the manufacturing process and materials used on the functioning and reliability of the final device also need to be addressed. Initial work on accurately determining several key mechanical properties of bonding pads, solder bumps and coatings using a combination of different methods and equipment has been summarized.

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