A device for testing mechanical properties of biological materials--the "Biodyne"

1975 ◽  
Vol 39 (5) ◽  
pp. 863-867 ◽  
Author(s):  
J. G. Pinto ◽  
J. M. Price ◽  
Y. C. Fung ◽  
E. H. Mead
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
System Performance ◽  
Soft Tissues ◽  
Biological Materials ◽  
Material Testing ◽  
Stress Strain ◽  
Manual Operation ◽  
Testing Procedures ◽  
As Stress

An electromechanical servo-controlled device has been developed. This device can be used to test the mechanical behavior of a wide variety of biological soft tissues. Control and execution of material testing procedures such as stress-strain, vibration, relaxation, creep etc. can be performed by manual operation of the device or by interfacing it with a laboratory type minicomputer. Experiments on excitable tissues such as muscle can also be executed. The design details and system performance are discussed.

Tissue Swelling During Extended Material Testing of Ligaments

2007 ◽  
Author(s):  
Trevor J. Lujan ◽  
Clayton C. Underwood ◽  
Nathan T. Jacobs ◽  
Jeffrey A. Weiss
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Biological Tissue ◽  
Material Testing ◽  
Test Environment ◽  
Physiological Conditions ◽  
Specific Effects

Material testing is often used to characterize the mechanical properties of biological tissue and to understand the specific effects of treatments and pathologies on mechanical behavior. To have confidence in results from material testing, it is important that the test environment is repeatable between samples and that tests are performed in an environment that mimics physiological conditions.

Surface Texture and Mechanical Behavior of Claw Material in Beetle Dorcus titanus (Coleoptera: Lucanidae)

2013 ◽  
Vol 461 ◽  
pp. 305-312 ◽  
Author(s):  
Zhi Xian Yang ◽  
Ze Hua Liu ◽  
Zhen Dong Dai
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Hierarchical Structure ◽  
Surface Texture ◽  
Smooth Surface ◽  
Biological Materials ◽  
Industrial Products ◽  
Biomimetic Materials ◽  
Nanomechanical Properties ◽  
Synthetic Materials

Biomaterials have an integrated, hierarchical structure with outstanding mechanical properties which are far beyond those achieved by using the same synthetic materials. nanoindentation techniques have recently been adapted for studying the biological materials. In this paper, the surface texture and nanomechanical properties of claw material in beetle Dorcus titanus were investigated. It is founded that the claw possesses of an optimized shape as well as the non-smooth surface texture with many stripes like as the fullows close to the arc inside. The results of nanoindentation tests indicate that the modulus value of the claw cuticle near the tip (11.25±0.57 GPa) is over three times larger than that near the claw root (3.61±0.22 GPa) and there is an incremental hardness and modulus values from the claw root to the tip. Quantitive measurements on the nanomechanical properties of claw material could help to develop biomimetic materials suitable for industrial products.

Microstructural Characteristics of Polyurea and Polyurethanexerogels for Concrete Confinement with FRP System

2013 ◽  
Vol 742 ◽  
pp. 237-242 ◽  
Author(s):  
Mostafa Fakharifar ◽  
Zhi Bin Lin ◽  
Cheng Lin Wu ◽  
Shruti Mahadik-Khanolkar ◽  
Nicholas Leventis ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Pilot Study ◽  
Mechanical Behavior ◽  
Confined Concrete ◽  
Stress Strain ◽  
Microstructural Characteristics ◽  
Concrete Confinement ◽  
Energy Absorbing

Due to their exceptional mechanical properties,xerogels attract increasing attention forstructural applications. In this study, the mechanical behavior of two types of polymeric xerogelsis investigated. The excellent energy-absorbing capability of those xerogelsis demonstrated by their stress-strain relations with respect to their microstructure determined withscanning electron microscopy (SEM). A pilot study on the effects of xerogellayers in an FRP system for concrete confinementis conducted.Test results clearly indicatedthat the proposed multi-layer systemcan significantly increase the ductility of confined concrete.

scholarly journals Digital image correlation-based point-wise inverse characterization of heterogeneous material properties of gallbladder in vitro

2014 ◽  
Vol 470 (2167) ◽  
pp. 20140152 ◽  
Author(s):  
Katia Genovese ◽  
Luciana Casaletto ◽  
Jay D. Humphrey ◽  
Jia Lu
Keyword(s):  
Mechanical Properties ◽  
Extracellular Matrix ◽  
Material Properties ◽  
Soft Tissues ◽  
Applied Pressure ◽  
Heterogeneous Material ◽  
Image Correlation ◽  
Surface Geometry ◽  
Stress Strain ◽  
Full Field

Continuing advances in mechanobiology reveal more and more that many cell types, especially those responsible for establishing, maintaining, remodelling or repairing extracellular matrix, are extremely sensitive to their local mechanical environment. Indeed, it appears that they fashion the extracellular matrix so as to promote a ‘mechanical homeostasis’. A natural corollary, therefore, is that cells will try to offset complexities in geometry and applied loads with heterogeneous material properties in order to render their local environment mechanobiologically favourable. There is a pressing need, therefore, for hybrid experimental–computational methods in biomechanics that can quantify such heterogeneities. In this paper, we present an approach that combines experimental information on full-field surface geometry and deformations with a membrane-based point-wise inverse method to infer full-field mechanical properties for soft tissues that exhibit nonlinear behaviours under finite deformations. To illustrate the potential utility of this new approach, we present the first quantification of regional mechanical properties of an excised but intact gallbladder, a thin-walled, sac-like organ that plays a fundamental role in normal digestion. The gallbladder was inflated to a maximum local stretch of 120% in eight pressure increments; at each pressure pause, the entire three-dimensional surface was optically extracted, and from which the surface strains were computed. Wall stresses in each state were predicted from the deformed geometry and the applied pressure using an inverse elastostatic method. The elastic properties of the gallbladder tissue were then characterized locally using point-wise stress–strain data. The gallbladder was found to be highly heterogeneous, with drastically different stiffness between the hepatic and the serosal sides. The identified material model was validated through forward finite-element analysis; both the configurations and the local stress–strain patterns were well reproduced.

EFFECTS OF CULTURE PERIODS AND LOADING ON BIOMECHANICAL PROPERTIES OF SHEEP COLLAGEN FASCICLES

2014 ◽  
Vol 14 (06) ◽  
pp. 1440010
Author(s):  
AHMET C. CILINGIR
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Soft Tissues ◽  
Culture Media ◽  
Experimental Studies ◽  
Biomechanical Properties ◽  
Collagen Fibrils ◽  
Tangent Modulus ◽  
Control Group ◽  
Stress Strain

Soft tissues (e.g., tendon, skin, cartilage) change their dimensions and properties in response to applied mechanical stress/strain, which is called remodeling. Experimental studies using tissue cultures were performed to understand the biomechanical properties of collagen fascicles under mechanical loads. Collagen fascicles were dissected from sheep Achilles tendons and loaded under 1, 2, and 3 kg for 2, 4, and 6 days under culture. The mechanical properties of collagen fascicles after being loaded into the culture media were determined using tensile tester, and resultant stress–strain curves, tangent modulus, tensile strength, and strain at failure values were compared with those in a non-loaded and non-cultured control group of fascicles. The tangent modulus and tensile strength of the collagen fascicles increased with the increasing remodeling load after two days of culture. However, these values gradually decreased with the increasing culture period compared with the control group. According to the results obtained in this study, the mechanical properties of collagen fascicles were improved by loading at two days of culture, most likely due to the remodeling of collagen fibers. However, after a period of remodeling, local strains on the collagen fibrils increased, and finally, the collagen fibrils broke down, decreasing the mechanical properties of the tissue.

Mechanical Properties of the Epidermis and Stratum Corneum Determined by Submicron Indentation In Vitro

2009 ◽  
Author(s):  
Marion Geerligs ◽  
Lambert C. A. v. Breemen ◽  
Gerrit W. M. Peters ◽  
Paul A. J. Ackermans ◽  
Cees W. J. Oomens ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stratum Corneum ◽  
Mechanical Behavior ◽  
Soft Tissues ◽  
Sensory Nerve ◽  
Complex Nature ◽  
Outer Skin ◽  
Viable Epidermis

The outer skin layers are important drug and vaccine delivery targets in the treatment of diseases. These skin layers possess some important characteristics making them favorable sites for pain-free delivery with minimal damage: a rich population of immunologically sensitive cells as well as the lack of blood vessels and sensory nerve endings [1]. Until today, however, the development of effective cell targeting methods is acquainted with many challenges. A collective shortcoming is a poor understanding of the key mechanical properties of the outer skin layers, e.g. the stratum corneum and epidermis. The anisotropic, dynamic and very complex nature of skin makes it difficult to perform proper mechanical testing as well as to obtain reliable, reproducible data. The stratum corneum is an effective physical barrier of dead cells with a “brick-and-mortar” structure, while the viable epidermis mainly consists of actively migrating keratinocytes constantly undergoing massive morphological and compositional changes. As a consequence, the structure differences among the skin layers lead to significant variations in mechanical properties. Since there is no method available to determine the mechanical behavior of isolated viable epidermis in vivo or in vitro, the mechanical behavior of epidermis and stratum corneum only are investigated here. A commercially available indentation system has been adapted to enable the measurement of these thin soft tissues in an in vitro set up. Combining the outcomes of the two skin layer types leads to an assessment of the contribution of the viable epidermis to the mechanical behavior of skin. To our knowledge, no data have been published yet regarding mechanical bulk properties of (viable) epidermis, while no consistency exists with respect to those of the stratum corneum.

Investigation of the Effects of High Temperature Aging on the Mechanical Behavior of Lead Free Solders

2018 ◽  
Author(s):  
Mohammad S. Alam ◽  
K. M. Rafidh Hassan ◽  
Jeffrey C. Suhling ◽  
Pradeep Lall
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Mechanical Behavior ◽  
High Temperatures ◽  
Elevated Temperatures ◽  
Lead Free ◽  
Specimen Preparation ◽  
Stress Strain ◽  
Initial Modulus ◽  
Lead Free Solders

Lead free solders are renowned as interconnects in electronic packaging due to their relatively high melting point, attractive mechanical properties, thermal cycling reliability, and environment friendly chemical properties. The mechanical behavior of lead free solders is highly dependent on the operating temperature. Previous investigations on mechanical characterization of lead free solders have mainly emphasized stress-strain and creep testing at temperatures up to 125 °C. However, electronic devices, sometimes, experience harsh environment applications including well drilling, geothermal energy, automotive power electronics, and aerospace engines where solders are exposed to very high temperatures from 125–200 °C. Mechanical properties of lead free solders at elevated temperatures are limited. In this work, we have investigated the mechanical behavior SAC305 (96.5Sn-3.0Ag-0.5Cu) and SAC_Q (SAC+Bi) lead free solders at extreme high temperatures up to 200 °C. Stress-strain tests were performed on reflowed uniaxial specimens at four elevated temperatures (T = 125, 150, 175, and 200 °C). In addition, changes of the mechanical behavior of these alloys due to isothermal aging at T = 125 °C have been studied. Extreme care has been taken during specimen preparation so that the fabricated solder uniaxial test specimens accurately reflect the solder material microstructures present in actual lead free solder joints. High temperature tensile properties of the solders including initial modulus, yield stress, and ultimate tensile strength have been compared. As expected, our results show substantial degradations of the mechanical properties of lead-free solders at higher temperatures. With prior aging, these degradations become even more significant. Comparison of the results has shown that the addition of Bi to traditional SAC alloys improves their high temperature properties and significantly reduces their aging induced degradations.

Effects of Moisture Exposure on the Mechanical Behavior of Polymer Encapsulants in Microelectronic Packaging

2013 ◽  
Author(s):  
Nusrat J. Chhanda ◽  
Jeffrey C. Suhling ◽  
Pradeep Lall
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Testing Machine ◽  
Adsorbed Water ◽  
Ultimate Tensile Stress ◽  
Stress Strain ◽  
Uniaxial Test ◽  
Organic Structure ◽  
Strain Behavior ◽  
Humidity Chamber

Polymer encapsulants exhibit evolving properties that change significantly with environmental exposures such as moisture uptake, isothermal aging and thermal cycling. In this study, the effects of moisture adsorption on the stress-strain behavior of a polymer encapsulant were evaluated experimentally. The uniaxial test specimens were exposed in an adjustable thermal and humidity chamber to combined hygrothermal exposures at 85 °C/85% RH for various durations. After moisture preconditioning, a microscale tension-torsion testing machine was used to evaluate the complete stress-strain behavior of the material at several temperatures. It was found that moisture exposure caused plasticization and strongly reduced the mechanical properties of the encapsulant including the initial elastic modulus and ultimate tensile stress. Reversibility tests were also conducted to evaluate whether the degradations in the mechanical properties were recoverable. Upon fully redrying, the polymer was found to recover most but not all of its original mechanical properties. As revealed by FTIR, some of the adsorbed water had been hydrolyzed in the organic structure of the epoxy-based adhesive, causing permanent changes to the mechanical behavior.

Mechanics of Wavy Network With Diamond-Shaped Inclusions

2017 ◽  
Author(s):  
Mona Monsef Khoshhesab ◽  
Yaning Li
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Mechanical Behavior ◽  
Geometric Constraints ◽  
Cellular Solids ◽  
Biomedical Devices ◽  
Stress Strain ◽  
Engineering Applications ◽  
Smart Composites ◽  
Strain Behavior

In this investigation, mechanical behavior of periodic cellular solids with diamond-shaped inclusions connected via wavy network were explored. Two families of cellular solids within this category were designed based on two different geometric constraints. Auxetic effects and snap-through instability were observed for each family, respectively. The mechanical properties, including the stress-strain behavior, stiffness and Poisson’s ratio, were systematically quantified via finite element (FE) simulations. The parametric space for auxetic effects and snap-through instability was numerically identified. This study demonstrates the connection and transition between mechanical auxeticity and snap-through instability. The materials designed have potential engineering applications, such as lightweight supporting and protective foams, biomedical devices, smart composites or fabrics with switchable properties responsive to external environments.

Mechanical Properties and Friction of AZ31 Magnesium Alloy and Application to the Cylidrical Deep Drawing Process

2017 ◽  
Vol 739 ◽  
pp. 225-230 ◽  
Author(s):  
Tung Sheng Yang ◽  
Guo Zhou Chen
Keyword(s):  
Mechanical Properties ◽  
Deep Drawing ◽  
Elevated Temperatures ◽  
Testing Machine ◽  
Fem Simulation ◽  
Drawing Process ◽  
Stress Strain ◽  
Deep Drawing Process ◽  
Friction Testing ◽  
As Stress

The mechanical properties such as stress-strain curves and anisotropic parameters at different elevated temperatures are obtained by the computerized screw universal testing machine. The friction testing machine is used to determine the friction coefficient between die and AZ31 sheets at different elevated temperatures. The finite element method is used to investigate the earing of the deep drawing process. In order to verify the prediction of FEM simulation of the earing in the cylindrical cup drawing process, the experimental parameters such as stress-strain curves, anisotropic parameters, fiction coefficient and blank holder force, are as the input data during analysis. The experimental cup height compared with the current simulation result of cylindrical deep drawing process at different elevated temperature.

Sign in / Sign up

Export Citation Format

Share Document