Passive Biaxial Mechanical Response of Aged Human Iliac Arteries

2003 ◽  
Vol 125 (3) ◽  
pp. 395-406 ◽  
Author(s):  
Christian A. J. Schulze-Bauer ◽  
Christian Mo¨rth ◽  
Gerhard A. Holzapfel
Keyword(s):  
Experimental Data ◽  
Deformation Behavior ◽  
Arterial Wall ◽  
Constitutive Models ◽  
Intraluminal Pressure ◽  
Clear Correlation ◽  
Outer Diameter ◽  
Iliac Arteries ◽  
Arterial Wall Mechanics

Inflation and extension tests of arteries are essential for the understanding of arterial wall mechanics. Data for such tests of human arteries are rare. At autopsy we harvested 10 non-diseased external iliac arteries of aged subjects (52–87 yrs). Structural homogeneity was ensured by means of ultrasound imaging, and anamneses of patients were recorded. We measured the axial in situ stretches, load-free geometries and opening angles. Passive biaxial mechanical responses of preconditioned cylindrical specimens were studied in 37°C calcium-free Tyrode solution under quasistatic loading conditions. Specimens were subjected to pressure cycles varying from 0 to 33.3kPa (250mmHg) at nine fixed axial loads, varying from 0 to 9.90N. For the description of the load-deformation behavior we employed five “two-dimensional” orthotropic strain-energy functions frequently used in arterial wall mechanics. The associated constitutive models were compared in regard to their ability of representing the experimental data. Histology showed that the arteries were of the muscular type. In contrast to animal arteries they exhibited intimal layers of considerable thickness. The average ratio of wall thickness to outer diameter was 7.7, which is much less than observed for common animal arteries. We found a clear correlation between age and the axial in situ stretch λis(r=−0.72,P=0.03), and between age and distensibility of specimens, i.e. aged specimens are less distensible. Axial in situ stretches were clearly smaller (1.07±0.09,mean±SD) than in animal arteries. For one specimen λis was even smaller than 1.0, i.e. the vessel elongated axially upon excision. The nonlinear and anisotropic load-deformation behavior showed small hystereses. For the majority of specimens we observed axial stretches smaller than 1.3 and circumferential stretches smaller than 1.1 for the investigated loading range. Data from in situ inflation tests showed a significant increase of the axial stretch with intraluminal pressure. Thus, for this type of artery the axial in situ stretch of a non-pressurized vessel is not representative of the axial in vivo stretch. None of the constitutive models were able to represent the deformation behavior of the entire loading range. For the physiological loading range, however, some of the models achieved good agreement with the experimental data.

Experimental and Numerical Investigations on Hot Deformation Behavior and Processing Maps for ASS 304 and ASS 316

2018 ◽  
Vol 37 (9-10) ◽  
pp. 873-888 ◽  
Author(s):  
Nitin Kotkunde ◽  
Hansoge Nitin Krishnamurthy ◽  
Swadesh Kumar Singh ◽  
Gangadhar Jella
Keyword(s):  
Experimental Data ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Constitutive Models ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Processing Maps ◽  
Hot Deformation Behavior ◽  
Statistical Measures

AbstractA thorough understanding of hot deformation behavior plays a vital role in determining process parameters of hot working processes. Firstly, uniaxial tensile tests have been performed in the temperature ranges of 150 °C–600 °C and strain rate ranges of 0.0001–0.01s−1 for analyzing the deformation behavior of ASS 304 and ASS 316. The phenomenological-based constitutive models namely modified Fields–Backofen (m-FB) and Khan–Huang–Liang (KHL) have been developed. The prediction capability of these models has been verified with experimental data using various statistical measures. Analysis of statistical measures revealed KHL model has good agreement with experimental flow stress data. Through the flow stresses behavior, the processing maps are established and analyzed according to the dynamic materials model (DMM). In the processing map, the variation of the efficiency of the power dissipation is plotted as a function of temperature and strain rate. The processing maps results have been validated with experimental data.

scholarly journals Iliac Veins Are More Compressible Than Iliac Arteries: A New Method of Testing

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Margaret Brass ◽  
Ghassan S. Kassab
Keyword(s):  
Arterial Wall ◽  
Fluid Transport ◽  
Vascular Wall ◽  
Fluid Loss ◽  
Loading Conditions ◽  
Vein Wall ◽  
Iliac Arteries ◽  
Direct Measurements ◽  
Arterial Wall Mechanics ◽  
Venous Wall

Incompressibility implies that a tissue preserves its volume regardless of the loading conditions. Although this assumption is well-established in arterial wall mechanics, it is assumed to apply for the venous wall without validation. The objective of this study is to test whether the incompressibility assumption holds for the venous wall. To investigate the vascular wall volume under different loading conditions, inflation-extension testing protocol was used in conjunction with intravascular ultrasound (IVUS) in both common iliac arteries (n = 6 swine) and common iliac veins (n = 9 dogs). Use of IVUS allows direct visualizations of lumen dimensions simultaneous with direct measurements of outer dimensions during loading. The arterial tissue was confirmed to preserve volume during various load conditions (p = 0.11) consistent with the literature, while the venous tissue was found to lose volume (about 35%) under loaded conditions (p < 0.05). Using a novel methodology, this study shows the incompressibility assumption does not hold for the venous wall especially at higher pressures, which suggests that there may be fluid loss through the vein wall during loading. This has important implications for coupling of fluid transport across the wall and biomechanics of the wall in healthy and diseased conditions.

Arterial wall properties and dietary atherosclerosis in the racing greyhound

1979 ◽  
Vol 236 (6) ◽  
pp. H790-H797 ◽  
Author(s):  
R. H. Cox ◽  
D. K. Detweiler
Keyword(s):  
Smooth Muscle ◽  
Muscle Activation ◽  
Arterial Wall ◽  
Carotid Arteries ◽  
External Diameter ◽  
Iliac Arteries ◽  
Force Development ◽  
Maximum Range ◽  
Arterial Wall Mechanics ◽  
Elastic Elements

The effects of experimental (dietary) atherosclerosis on arteries from racing greyhounds were studied. Measurements of pressure and external diameter were made on islated carotid and iliac arteries under active (norepinephrine, 5 microgram/ml) and passive (zero Ca2+ and 2 mM EGTA) smooth muscle conditions. Iliac arteries from diet-fed animals demonstrated substantial intimal lesions, but the carotid arteries were usually grossly involved. Arteries from atherosclerotic animals were stiffer during passive conditions, with the iliac arteries having the greater changes. In iliac arteries from treated animals, collagen and elastin contents were decreased, and the collagen-to-elastin ratio was increased; in carotid arteries from treated animals, elastin content was increased and the collagen-to-elastin ratio was decreased. The maximum range of control of arterial wall mechanics by smooth muscle was diminished in treated iliacs but unchanged in carotids. Both force development and constriction responses associated with smooth muscle activation were diminished in treated iliacs but unchanged in treated carotids. Mechanical properties of series elastic elements in treated iliacs were stiffer, but treated carotids were unchanged.

Comparison of arterial wall mechanics using ring and cylindrical segments

1983 ◽  
Vol 244 (2) ◽  
pp. H298-H303 ◽  
Author(s):  
R. H. Cox
Keyword(s):  
Arterial Wall ◽  
Muscle Length ◽  
Stress And Strain ◽  
Active Force ◽  
Cross Sectional ◽  
Iliac Arteries ◽  
Force Development ◽  
Arterial Wall Mechanics ◽  
Length Data ◽  
Passive Mechanics

Thin rings and intact cylindrical segments of canine carotid and iliac arteries were used to determine wall mechanics. Measurements of force and length were obtained from the ring segments, whereas measurements of pressure and diameter were obtained from the cylindrical segments under conditions of active (147 mM K+) and passive smooth muscle (Ca2+ free and 2 mM ethyleneglycolbis (beta-aminoethylether)-N,N'-tetraacetic acid). These measurements were normalized to values of segment stress and strain. Under passive conditions stress-strain relations for the rings appeared to be stiffer than those obtained using cylindrical segments. Pressure-diameter curves computed using force-length data from the rings were shifted to higher values of diameter compared with values from the intact segments at all pressure levels. Passive mechanics derived from measurements on ring segments yielded poor estimates of mechanics derived from intact segments. Despite this finding, values of active force development from the two sample geometries were similar. No statistically significant differences were found in values of maximum force development expressed in terms of sample cross-sectional area. Some differences in values of active force development at low values of muscle length were found. The latter were probably related to the differences in passive mechanics and the procedure used to normalize muscle length. Reasonable values of active force development can be obtained from ring segments.

Percutaneous Infusion System for In Situ Thrombolysis in the Abdominal Aorta and Iliac Arteries

2002 ◽  
Vol 9 (6) ◽  
pp. 932-935 ◽  
Author(s):  
Roberto Fernandez Viña ◽  
Federico Benetti ◽  
Francisco Vrsalovick ◽  
José Luis Rizzardi ◽  
Danilo Petroni ◽  
...  
Keyword(s):  
Abdominal Aorta ◽  
Iliac Arteries ◽  
Infusion System

In Situ Study on the Compression Deformation Behavior of MoNbTaVW High-Entropy Alloy

2020 ◽  
Author(s):  
Congyan Zhang ◽  
Binbin Yue ◽  
Uttam Bhandari ◽  
Oleg Starovoytov ◽  
Yan Yang ◽  
...  
Keyword(s):  
Deformation Behavior ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Compression Deformation

scholarly journals Study on Microstructure and In Situ Tensile Deformation Behavior of Fe-25Mn-xAl-8Ni-C Alloy Prepared by Vacuum Arc Melting

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 814
Author(s):  
Yaping Bai ◽  
Meng Li ◽  
Chao Cheng ◽  
Jianping Li ◽  
Yongchun Guo ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Deformation Behavior ◽  
Tensile Deformation ◽  
Austenite Phase ◽  
Vacuum Arc ◽  
Al Content ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
Tensile Deformation Behavior

In this study, Fe-25Mn-xAl-8Ni-C alloys (x = 10 wt.%, 11 wt.%, 12 wt.%, 13 wt.%) were prepared by a vacuum arc melting method, and the microstructure of this series of alloys and the in situ tensile deformation behavior were studied. The results showed that Fe-25Mn-xAl-8Ni-C alloys mainly contained austenite phase with a small amount of NiAl compound. With the content of Al increasing, the amount of austenite decreased while the amount of NiAl compound increased. When the Al content increased to 12 wt.%, the interface between austenite and NiAl compound and austenitic internal started to precipitate k-carbide phase. In situ tensile results also showed that as the content of Al increased, the alloy elongation decreased gradually, and the tensile strength first increased and then decreased. When the Al content was up to 11 wt.%, the elongation and tensile strength were 2.6% and 702.5 MPa, respectively; the results of in situ tensile dynamic observations show that during the process of stretching, austenite deformed first, and crack initiation mainly occurred at the interface between austenite and NiAl compound, and propagated along the interface, resulting in fracture of the alloy.

scholarly journals Ability of Constitutive Models to Characterize the Temperature Dependence of Rubber Hyperelasticity and to Predict the Stress-Strain Behavior of Filled Rubber under Different Defor Mation States

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 369
Author(s):  
Xintao Fu ◽  
Zepeng Wang ◽  
Lianxiang Ma
Keyword(s):  
Experimental Data ◽  
Temperature Dependence ◽  
Mechanical Response ◽  
Constitutive Models ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Chain Model ◽  
Stress Strain ◽  
Filled Rubber ◽  
Yeoh Model

In this paper, some representative hyperelastic constitutive models of rubber materials were reviewed from the perspectives of molecular chain network statistical mechanics and continuum mechanics. Based on the advantages of existing models, an improved constitutive model was developed, and the stress–strain relationship was derived. Uniaxial tensile tests were performed on two types of filled tire compounds at different temperatures. The physical phenomena related to rubber deformation were analyzed, and the temperature dependence of the mechanical behavior of filled rubber in a larger deformation range (150% strain) was revealed from multiple angles. Based on the experimental data, the ability of several models to describe the stress–strain mechanical response of carbon black filled compound was studied, and the application limitations of some constitutive models were revealed. Combined with the experimental data, the ability of Yeoh model, Ogden model (n = 3), and improved eight-chain model to characterize the temperature dependence was studied, and the laws of temperature dependence of their parameters were revealed. By fitting the uniaxial tensile test data and comparing it with the Yeoh model, the improved eight-chain model was proved to have a better ability to predict the hyperelastic behavior of rubber materials under different deformation states. Finally, the improved eight-chain model was successfully applied to finite element analysis (FEA) and compared with the experimental data. It was found that the improved eight-chain model can accurately describe the stress–strain characteristics of filled rubber.

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