Age-Related Differences in the Biaxial Biomechanical Behavior of Human Abdominal Aorta

2002 ◽  
Author(s):  
Jonathan P. Vande Geest ◽  
Michael S. Sacks ◽  
David A. Vorp
Keyword(s):  
Tensile Testing ◽  
Mechanical Response ◽  
Uniaxial Tensile ◽  
Aortic Tissue ◽  
Orthogonal Direction ◽  
Biomechanical Behavior ◽  
Uniaxial Tensile Testing ◽  
Age Related ◽  
Abdominal Aortic ◽  
Biomechanical Response

The biomechanical response of abdominal aortic tissue to uniaxial loading conditions has been reported previously [1]. This testing identified the uniaxial mechanical response of aortic tissue to specimens oriented in the longitudinal and circumferential directions, but did not provide significant evidence for the isotropy or anisotropy of this tissue. The information taken from uniaxial tensile testing is insufficient for the characterization of the multi-axial mechanical response of aortic tissue. In particular, the uniaxial response of a biological tissue in a given direction does not incorporate the effects of loading in an orthogonal direction. For these reasons, there exists a need for an enhanced description of the mechanical response of aortic tissue to loading in multiple planar directions. For the current investigation, biaxial tensile testing was performed on normal abdominal aortic tissue in order to gain insight into the anisotropy and age related differences of the biomechanical response of this tissue.

On the Mechanical Behavior of Healthy and Aneurysmal Abdominal Aorta

2011 ◽  
Author(s):  
J. Ferruzzi ◽  
M. S. Enevoldsen ◽  
J. D. Humphrey
Keyword(s):  
Mechanical Behavior ◽  
Abdominal Aorta ◽  
Arterial Wall ◽  
Mechanical Response ◽  
Pathological Condition ◽  
Uniaxial Tensile ◽  
Infrarenal Aorta ◽  
Biaxial Testing ◽  
Biomechanical Behavior ◽  
Uniaxial Tensile Testing

Abdominal aortic aneurysm (AAA) is a pathological condition of the infrarenal aorta characterized by a local dilatation of the arterial wall. The main histopathologic features of an AAA are smooth muscle cell death and loss of elastin. The biomechanical behavior of AAAs has been widely studied to determine the rupture potential according to the principles of material failure. However, most prior approaches are limited by the use of data from uniaxial tensile testing and by the assumption of material isotropy, leading to inaccurate characterization of the 3D multiaxial mechanical response of the aneurysmal tissue. To date, the best data available on the behavior of human abdominal aorta (AA) and AAA to planar biaxial testing are the ones reported by Vande Geest et al. [1,2]. In a recent work [3], we considered a structurally motivated four-fiber family strain energy function (SEF) [4] to capture the biaxial behavior of the human AA and AAA from Vande Geest et al. [1,2]. We showed that this constitutive relation fits human data better than prior models and most importantly it captures the stiffening of the arterial wall related to both aging and aneurysmal development. These changes in mechanical behavior are mirrored by changes in the best-fit values of the parameters, with a progressive decrease of the isotropic part attributed to elastin and a parallel increase in values associated with the families of collagen fibers.

Mechanical behavior of chemically treated ostrich pericardium subjected to uniaxial tensile testing: influence of the suture

2002 ◽  
Vol 62 (1) ◽  
pp. 73-81 ◽  
Author(s):  
J. M. García Páez ◽  
A. Carrera ◽  
E. Jorge Herrero ◽  
I. Millán ◽  
A. Rocha ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Tensile Testing ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Testing ◽  
Chemically Treated

A Novel MEMS-Based Technique for In-Situ Characterization of Freestanding Nanometer Scale Thin Films Inside SEM and TEM

2001 ◽  
Author(s):  
M. A. Haque ◽  
M. T. A. Saif
Keyword(s):  
Thin Films ◽  
Tensile Testing ◽  
Uniaxial Tensile ◽  
Aluminum Specimen ◽  
Sem And Tem ◽  
Uniaxial Tensile Testing ◽  
Testing Facility ◽  
Film Specimen ◽  
On Chip

Abstract We present a MEMS-based technique for in-situ uniaxial tensile testing of freestanding thin films inside SEM and TEM. It integrates a freestanding thin film specimen with MEMS force sensors and structures to produce an on-chip tensile testing facility. Cofabrication of the specimen with force and displacement measuring mechanisms produces the following unique features: 1) Quantitative experimentation can be carried out in both SEM and TEM, 2) No extra gripping mechanism is required, 3) Specimen misalignment can be eliminated, 4) Pre-stress in specimen can be determined, and 5) Specimens with micrometer to nanometer thickness can be tested. We demonstrate the technique by testing a 200-nanometer thick Aluminum specimen in-situ in SEM. Significant strengthening and anelasticity were observed at this size scale.

scholarly journals Length Scale and Aging Effect on the Mechanical Properties of a 63Sn-37Pb Solder Alloy

2000 ◽  
Author(s):  
T. Jesse Lim ◽  
Wei-Yang Lu
Keyword(s):  
Ultimate Strength ◽  
Tensile Testing ◽  
Failure Strain ◽  
Aging Effect ◽  
Uniaxial Tensile ◽  
Strain Response ◽  
Stress Strain ◽  
Uniaxial Tensile Testing ◽  
Aging Conditions ◽  
Strain Responses

Abstract In this work, uniaxial tensile testing of a 63Sn-37Pb alloy with different specimen sizes and aging conditions had been carried out. Although the stress-strain responses of different specimen sizes and aging conditions differs, the ultimate strength of the specimens with 16 hours, 100°C aging are similar for the sizes tested. The specimens with 25 days, 100°C aging have different stress-strain response with different sizes, and have a lower ultimate strength and higher failure strain compared to 16 hours, 100°C aging specimens.

scholarly journals Simulation of failure processes of as-cast Ti-5Al-5Nb-1Mo-1V-1Fe titanium alloy subjected to quasi-static uniaxial tensile testing

2019 ◽  
Vol 180 ◽  
pp. 107962
Author(s):  
Haichao Gong ◽  
Qunbo Fan ◽  
Yu Zhou ◽  
Duoduo Wang ◽  
Pengru Li ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Tensile Testing ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Testing

Specimen Geometry Study for Direct Tension Test Based on Mechanical Tests and Air Void Variation in Asphalt Concrete Specimens Compacted by Superpave Gyratory Compactor

2000 ◽  
Vol 1723 (1) ◽  
pp. 125-132 ◽  
Author(s):  
Ghassan R. Chehab ◽  
Emily O’Quinn ◽  
Y. Richard Kim
Keyword(s):  
Asphalt Concrete ◽  
Tensile Testing ◽  
Complex Modulus ◽  
Specimen Geometry ◽  
Uniaxial Tensile ◽  
Void Content ◽  
Uniaxial Tensile Testing ◽  
Superpave Gyratory Compactor ◽  
Air Void ◽  
Air Void Content

Reliable materials characterization and performance prediction testing of asphalt concrete requires specimens that can be treated as statistically homogeneous and representative of the material being tested. The objective of this study was to select a proper specimen geometry that could be used for uniaxial tensile testing. Selection was based on the variation of air void content along the height of specimens cut and cored from specimens compacted by the Superpave gyratory compactor (SGC) and on the representative behavior under mechanical testing. From measurement and comparison of air void contents in cut and cored specimens, it was observed for several geometries that sections at the top and bottom and those adjacent to the mold walls have a higher air void content than do those in the middle. It is thus imperative that test specimens be cut and cored from larger-size SGC specimens. Complex modulus and constant crosshead-rate monotonic tests were conducted for four geometries—75 × 115, 75 × 150, 100 × 150, and 100 × 200 mm—to study the effect of geometry boundary conditions on responses. On the basis of graphical and statistical analysis, it was determined that there was an effect on the dynamic modulus at certain frequencies but no effect on the phase angle. Except for 75 × 115 mm, all geometries behaved similarly under the monotonic test. From these findings and other considerations, it is recommended that the 75- × 150-mm geometry, which is more conservative, and the 100- × 150-mm geometry be used for tensile testing.

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