bulk properties exam 1 Flashcards
what is stress
mechanical force/area applied to material
what is strain
mechanical deformation in response to stress
what is modulus
slope of stress vs. strain curve
what is the most commonly used isotropic modulus
young’s modulus (E) for tension and compression, and shear modulus (G) for shearing
how is young’s modulus measured
using tensile/compressive testing (the elastic modulus)
how is shear modulus measured
using shear stress and measuring elastic response
what do brittle failures indicate
an inability of material to withstand plastic deformation, which leads to catastrophic failure
what does ductile failure indicate
material can withstand large plastic deformation
what is toughness
the amount of energy absorbed by material prior to failure
what is the relationship between being strong and stress
strong = can take high stress
what is the toe region
region before linear behaviors are shown
when do soft biomaterials have a toe region
when fresh in a stress-strain relationship; none when frozen tissue
what is the comparison between bulk and theoretical properties
bulk properties < theoretical properties (derived from the strong and weak interactions)
what is critical for predicting biomaterial behavior
knowledge of how physiological environment will affect microstructure
what do bulk material properties change under
time, dynamic/cyclic loading conditions, temperature
what are anisotropic properties
natural biomaterials have these based on their function
what are the main four bulk properteis
mechanical, chemical, thermal, electrical
what are examples of mechanical properties
stiffness, modulus, strength, toughness, ductility
what are examples of chemical properties
degradation properties, permeability, swelling in solution, diffusivity
what are examples of thermal properties
glassy/amorphous transition, conductivity, heat capacity, thermal absorption, thermal capacitance
what are examples of electrical properties
conductivity, permittivity, polarization, piezoelectricity
what are the two types of mechanical properties biomaterials exhibit
linear (elastic)
nonlinear (plastic)
