ISO 18437-4:2008 機械的振動と衝撃—粘弾性材料の動的機械的特性の特性評価—パート4：動的剛性法 | ページ 6

3.1

dynamic mechanical properties

fundamental elastic properties, i.e., elastic modulus, shear modulus, bulk modulus and loss factor

3.2

damped structure

structure containing elements made from damping materials

3.3

Young modulus

modulus of elasticity

E

ratio of the normal stress to linear strain

Note 1 to entry: Adapted from ISO 80000-4-18.1:2006 ^[9] .

Note 2 to entry: The Young modulus is expressed in pascals.

Note 3 to entry: The complex Young modulus, E *, for a visco-elastic material is represented by E * = E ʹ + i E ″ ここで, E ʹ is the real (elastic) component of the Young modulus and E ″ is the imaginary (loss modulus) component of the Young modulus. The real component represents elastically stored mechanical energy, while the imaginary component is a measure of mechanical energy loss.

3.4

shear modulus

modulus of rigidity

Coulomb modulus

G

ratio of the shear stress to the shear strain

Note 1 to entry: Adapted from ISO 80000-4-18.2:2006 ^[9] .

Note 2 to entry: The shear modulus is expressed in pascals.

Note 3 to entry: The complex shear modulus, G *, for a visco-elastic material is represented by G * = G ʹ + i G ″ ここで, G ʹ is the real (elastic) component of the shear modulus and G ″ is the imaginary (loss modulus) component of the shear modulus.

3.5

bulk modulus

modulus of compression

K

the negative ratio of pressure to volume strain

Note 1 to entry: Adapted from ISO 80000-4-18.3:2006 ^[9] .

Note 2 to entry: The bulk modulus is expressed in pascals.

Note 3 to entry: The complex bulk modulus is represented by K * = K ʹ + i K ″ ここで, K ʹ is the real (elastic) component of the bulk modulus and K ″ is the imaginary (loss modulus) component of the bulk modulus.

3.6

loss factor

ratio of the imaginary component to the real component of a complex modulus

Note 1 to entry: When a material shows a phase difference, δ, between dynamic stress and strain in harmonic deformations, the loss factor is equal to tanδ.

3.7

magnitude of complex modulus

absolute value of the complex modulus

3.8

frequency-temperature superposition

principle by which, for visco-elastic materials, frequency and temperature are equivalent to the extent that data at one temperature can be superimposed upon data taken at different temperature merely by shifting the data curves along the frequency axis

3.9

shift factor

measure of the amount of shift along the logarithmic axis of frequency for one set of data at one temperature to superimpose upon another set of data at another temperature

3.10

glass transition temperature

T_g

temperature at which a material changes state reversibly from glassy to rubbery

Note 1 to entry: The glass transition temperature is expressed in degrees Celsius.

Note 2 to entry: The glass transition temperature is typically determined from the inflection point of a specific heat vs. temperature plot and represents an intrinsic material property.

Note 3 to entry:T_g is not the peak in the dynamic mechanical loss factor. That peak occurs at a temperature higher than T_g and varies with the measurement frequency, hence it is not an intrinsic material property.

3.11

linearity

property of dynamic behaviour of a resilient material if it satisfies the principle of superposition

Note 1 to entry: The principle of superposition can be stated as follows: if an input x₁( t ) produces an output y₁( t ) and in a separate test an input x₂( t ) produces an output y₂( t ), superposition holds if the input αx₁( t ) + βx₂( t ) produces the output αy₁( t ) + βy₂( t ) ここで, α and β are arbitrary constants. This must hold for all values of α, β and x₁( t ), x₂( t ).

Note 2 to entry: In practice, the above test for linearity is impractical and a limited check of linearity is done by measuring the dynamic modulus for a range of input levels. For a specific preload, if the dynamic modulus is nominally invariant, the system measurement can be considered linear. In effect, this procedure checks for a proportional relationship between the response and the excitation.