ISO 527-4:2023 プラスチック — 引張特性の測定 — Part 4: 等方性および直交異方性の繊維強化プラスチック複合材の試験条件 | ページ 6

3.1

gauge length

L₀

initial distance between the gauge marks on the central part of the test specimen

Note 1 to entry: It is expressed in millimetres (mm).

Note 2 to entry: The values of the gauge length that are indicated for the specimen types in the different parts of ISO 527 represent the maximum relevant gauge length.

[SOURCE:ISO 527-1:2019, 3.1]

3.2

thickness

h

smaller initial dimension of the rectangular cross-section in the central part of a test specimen

Note 1 to entry: It is expressed in millimetres (mm).

[SOURCE:ISO 527-1:2019, 3.2]

3.3

width

b

larger initial dimension of the rectangular cross-section in the central part of a test specimen

Note 1 to entry: It is expressed in millimetres (mm).

[SOURCE:ISO 527-1:2019, 3.3]

3.4

test speed

v

rate of separation of the gripping jaws

Note 1 to entry: It is expressed in millimetres per minute (mm/min).

[SOURCE:ISO 527-1:2019, 3.5]

3.5

stress

σ

<engineering> normal force per unit area of the original cross-section within the gauge length (3.1)

Note 1 to entry: It is expressed in megapascals (MPa).

Note 2 to entry: In order to differentiate from the true stress related to the actual cross-section of the specimen, this stress is frequently called “engineering stress”.

Note 3 to entry:σ for “1"-direction specimens is defined as σ₁ and for"2"-direction specimens as σ₂ (see 3.9 and Figure 2 for definitions of these directions).

[SOURCE:ISO 527-1:2019, 3.6, modified — Domain “<engineering>” and Note 3 to entry have been added.]

3.5.1

strength

σ_m

maximum stress observed during a tensile test

Note 1 to entry: It is expressed in megapascals (MPa).

[SOURCE:ISO 527-1:2019, 3.6.2]

3.6

strain

ε

increase in length per unit original length of the gauge

Note 1 to entry: It is expressed as a dimensionless ratio, or as a percentage (%).

[SOURCE:ISO 527-1:2019, 3.7]

3.6.1

strain at strength

ε_m

strain at which the strength (3.5.1) is reached

Note 1 to entry: It is expressed as a dimensionless ratio, or as a percentage (%).

[SOURCE:ISO 527-1:2019, 3.7.3]

3.7

tensile modulus

modulus of elasticity under tension

E_t

slope of the stress/strain curve σ(ε) in the interval between the two strains ε₁ = 0,05 % and ε₂ = 0,25 %

Note 1 to entry: It is expressed in megapascals (MPa).

Note 2 to entry: It may be calculated either as the chord modulus or as the slope of a linear least-squares regression line in this interval.

Note 3 to entry: This definition does not apply to films.

Note 4 to entry: See Figure 1.

[SOURCE:ISO 527-1:2019, 3.9]

Figure 1 — Stress-strain curve

Key

X	strain, ε
Y	stress, σ
a	slope E

3.8

Poisson's ratio

µ

negative ratio of the strain change Δε_n, in one of the two axes normal to the direction of extension, to the corresponding strain change Δε_l in the direction of extension, within the linear portion of the longitudinal versus normal strain curve

Note 1 to entry: It is expressed as a dimensionless ratio.

Note 2 to entry: Since the lateral strain change Δε_n is a negative number and the longitudinal strain change Δε_l is positive, the Poissons ratio as defined in ISO 527-1:2019, 3.10 is a positive number.

[SOURCE:ISO 527-1:2019, 3.10]

3.9

specimen coordinate axes

1, 2, 3

axes ここで, “1"-direction is normally defined in terms of a feature associated with the material structure or the production process, such as the length direction in continuous-sheet processes (see Figure 2) and the “2"-direction is perpendicular to the “1"-direction.

Note 1 to entry: The “1-direction is also referred to as the 0° or longitudinal direction and the “2’‘-direction as the 90° or transverse direction. The “3-direction” is perpendicular to the plane of the “1-direction” and “2-direction”. The “3-direction” is also referred to as the “through-thickness” direction for planar systems.

Note 2 to entry: For unidirectional materials covered by part 5 of this International Standard, the direction parallel to the fibres is defined as the “1"-direction and the direction perpendicular to the fibres (in the plane of the prepreg/plate) as the “2"-direction.

Figure 2 — Fibre-reinforced plastic composite showing axes of symmetry

3.10

failure position

u_F

failure location of specimen type 4 within the local coordinate system (u, v) of the tapered section

Note 1 to entry: It is expressed in millimetres (mm).

Note 2 to entry: See Figure 5.