High rate failure properties of porcine aortic tissue under uniaxial tension

Aortic allografts have been widely used in treatments of congenital heart diseases with satisfactory clinical outcomes. They were usually cryopreserved and stored for surgical use. The objective of this work was to investigate the effect of cold storage on mechanical properties of aorta, since the compliance mismatch was one important factor associated with the complication after graft surgery. The segments of porcine descending aorta were divided into two groups: the fresh samples which were tested within 24 hours after harvesting served as control group, and frozen samples which were stored in −20°C for 7 days and then thawed. The uniaxial tension tests along circumferential direction and indentation tests were conducted. The average incremental elastic moduli within each stretch range were obtained from the experimental data obtained during tension tests, and the elastic moduli were also calculated by fitting the force-indentation depth data to Hertz model when the tissue was stretched at 1.0, 1.2, 1.4 and 1.6. In addition, the average incremental elastic moduli of both fresh and frozen aortic tissue along axial direction were also obtained by using uniaxial tension tests. The comparison showed that cold storage definitely increased the average incremental elastic modulus of the aortic tissue along circumferential direction; however, the difference is not significant for the elastic moduli along axial direction.

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Strain-Rate-Dependent Tensile Response of Ti–5Al–2.5Sn Alloy

Materials ◽

10.3390/ma12040659 ◽

2019 ◽

Vol 12 (4) ◽

pp. 659 ◽

Cited By ~ 3

Author(s):

Bin Zhang ◽

Jin Wang ◽

Yang Wang ◽

Yu Wang ◽

Ziran Li

Keyword(s):

Strain Rate ◽

Strain Hardening ◽

Uniaxial Tension ◽

Temperature Rise ◽

High Strain ◽

Adiabatic Temperature ◽

High Rate ◽

Strain Rates ◽

High Strain Rates ◽

Adiabatic Temperature Rise

This study is an experimental investigation on the tensile responses of Ti–5Al–2.5Sn alloy over a wide range of strain rates. Uniaxial tension tests within the rate range of 10−3–101 s−1 are performed using a hydraulic driven MTS810 machine and a moderate strain-rate testing system. The high-rate uniaxial tension and tension recovery tests are conducted using a split-Hopkinson tension bar to obtain the adiabatic and isothermal stress–strain responses of the alloy under dynamic loading conditions. The experimental results show that the value of the initial yield stress increases with the increasing strain rate, while the strain rate sensitivity is greater at high strain rates. The isothermal strain-hardening behavior changes little with the strain rate, and the adiabatic temperature rise is the main reason for the reduction of the strain-hardening rate during high strain-rate tension. The electron backscatter diffraction (EBSD) analysis of the post-deformed samples indicates that there are deformation twins under quasi-static and high-rate tensile loadings. Scanning electron microscope (SEM) micrographs of the fracture surfaces of the post-deformed samples show dimple-like features. The Zerilli–Armstrong model is modified to incorporate the thermal-softening effect of the adiabatic temperature rise at high strain rates and describe the tension responses of Ti–5Al–2.5Sn alloy over strain rates from quasi-static to 1050 s−1.

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Strain energy characterisation of human aortic tissue in uniaxial tension

Journal of Biomechanics ◽

10.1016/0021-9290(84)90187-8 ◽

1984 ◽

Vol 17 (11) ◽

pp. 877

Author(s):

K.B. Sahay ◽

Dinesh Mohan

Keyword(s):

Uniaxial Tension ◽

Strain Energy ◽

Aortic Tissue

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Material Properties of the Post-Mortem Stomach in High-Rate Equibiaxial Elongation

ASME 2012 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2012-80842 ◽

2012 ◽

Author(s):

Meghan K. Howes ◽

Warren N. Hardy

Keyword(s):

Failure Modes ◽

Motor Vehicle ◽

High Rate ◽

Motor Vehicle Collisions ◽

Tissue Samples ◽

Vehicle Collisions ◽

Gastric Rupture ◽

Biomechanical Response ◽

Failure Properties ◽

Equibiaxial Elongation

Risk of serious abdominal injury in motor vehicle collisions (MVCs) is substantially reduced with the proper use of seatbelts [1]. However, a significant increase in occurrence of gastrointestinal tract injury exists with belt loading [2]. Crash-induced injuries of the stomach that occur in MVCs include gastric rupture and laceration [3]. To characterize the biomechanical response of the stomach associated with these failure modes, the multidirectional failure properties of cruciate tissue samples were investigated with high-rate biaxial stretch.

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Failure properties of passive human aortic tissue. II—Biaxial tension tests

Journal of Biomechanics ◽

10.1016/0021-9290(83)90044-1 ◽

1983 ◽

Vol 16 (1) ◽

pp. 31-44 ◽

Cited By ~ 91

Author(s):

Dinesh Mohan ◽

John W. Melvin

Keyword(s):

Biaxial Tension ◽

Aortic Tissue ◽

Tension Tests ◽

Failure Properties

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Structure of Palladium Single-Crystal Films Prepared by Flash Evaporation onto (001) NaCl Substrates

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069272 ◽

1970 ◽

Vol 28 ◽

pp. 456-457

Author(s):

L. E. Murr ◽

G. Wong

Keyword(s):

Single Crystal ◽

High Vacuum ◽

Ultra High Vacuum ◽

High Rate ◽

Flash Evaporation ◽

Optimum Load ◽

Single Crystal Films ◽

Crystal Films ◽

A Current

Palladium single-crystal films have been prepared by Matthews in ultra-high vacuum by evaporation onto (001) NaCl substrates cleaved in-situ, and maintained at ∼ 350° C. Murr has also produced large-grained and single-crystal Pd films by high-rate evaporation onto (001) NaCl air-cleaved substrates at 350°C. In the present work, very large (∼ 3cm2), continuous single-crystal films of Pd have been prepared by flash evaporation onto air-cleaved (001) NaCl substrates at temperatures at or below 250°C. Evaporation rates estimated to be ≧ 2000 Å/sec, were obtained by effectively short-circuiting 1 mil tungsten evaporation boats in a self-regulating system which maintained an optimum load current of approximately 90 amperes; corresponding to a current density through the boat of ∼ 4 × 104 amperes/cm2.

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Relationships between hierarchical structure and properties in macromolecular systems

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126950 ◽

1987 ◽

Vol 45 ◽

pp. 440-443

Author(s):

E. Baer

Keyword(s):

Uniaxial Tension ◽

Hierarchical Structure ◽

Inorganic Material ◽

Hierarchical Structures ◽

Bone Collagen ◽

Structure And Properties ◽

Connective Tissues ◽

Scale Level ◽

Fibrous Protein ◽

Macromolecular Systems

The most advanced macromolecular materials are found in plants and animals, and certainly the connective tissues in mammals are amongst the most advanced macromolecular composites known to mankind. The efficient use of collagen, a fibrous protein, in the design of both soft and hard connective tissues is worthy of comment. Very crudely, in bone collagen serves as a highly efficient binder for the inorganic hydroxyappatite which stiffens the structure. The interactions between the organic fiber of collagen and the inorganic material seem to occur at the nano (scale) level of organization. Epitatic crystallization of the inorganic phase on the fibers has been reported to give a highly anisotropic, stress responsive, structure. Soft connective tissues also have sophisticated oriented hierarchical structures. The collagen fibers are “glued” together by a highly hydrated gel-like proteoglycan matrix. One of the simplest structures of this type is tendon which functions primarily in uniaxial tension as a reinforced elastomeric cable between muscle and bone.

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