GB/T 18318.1-2009Textiles -- Determination of bending behavior -- Part 1: Incline method (English PDF)

Foreword

GB/T 18318 "Textiles - Determination of bending behavior" includes the

following parts:

- Part 1: Inclined method;

- Part 2: Heart loop method;

- Part 3: Gurley method;

- Part 4: Cantilever beam;

- Part 5: Pure bending method;

- Part 6: Saddle method.

This part is the part 1 of GB/T 18318.

This part uses the redrafting method to modify and adopt the ISO 9073-7:1995

"Textiles - Test methods for nonwovens - Part 7: Determination of bending

length". As compared with ISO 9073-7:1995, the main differences of this part

are as follows:

- MODIFY the standard name. EXPAND the scope of application, to make it

apply to not only non-woven fabrics, but also other types of fabrics;

- In the normative references, USE Chinese standards to replace

international standards; DELETE the referenced ISO 186 Cardboard

sampling method;

- In the normative references, ADD GB/T 4669 (see clauses 2 and 8.1);

- In clause 6, USE "Follow the provisions of product standards or relevant

agreements to take sample" to replace "Follow ISO 186 to take sample";

- DELETE the recording time "after (8 ± 2) s" in clause 8.2;

- ADD the calculation result "retain three significant figures" (see 9.3);

- MOVE the note to clause 9.3 into clause A.1 in Appendix A;

- DELETE the note 1 to clause and the note 8 to clause 8.2.

This part replaces GB/T 18318-2001 "Textiles - Determination of bending length

of fabrics". As compared with GB/T 18318-2001, the main differences of this

part are as follows:

Textiles - Determination of bending behavior -

Part 1: Incline method

1 Scope

This part of GB/T 18318 specifies the method of using the incline method to

determine the bending length of fabrics; gives the formula for calculating the

flexural rigidity according to the bending length.

This section applies to all types of fabrics.

2 Normative references

The provisions in following documents become the provisions of this part

through reference in this this part of GB/T 18318. For the dated references, the

subsequent amendments (excluding corrections) or revisions do not apply to

this part; however, parties who reach an agreement based on this standard are

encouraged to study if the latest versions of these documents are applicable.

For undated references, the latest edition of the referenced document applies.

GB/T 4669 Textiles - Woven fabrics - Determination of mass per unit length

and mass per unit area (GB/T 4669-2008, ISO 3801-1977, MOD)

GB/T 6529 Textiles - Standard atmospheres for conditioning and testing

(GB/T 6529-2008, ISO 139:2005, MOD)

GB/T 24218.1 Textiles - Test methods for nonwovens - Part 1: Determination

of mass per unit area (GB/T 24218.1-2009, ISO 9073-1:1995, MOD)

3 Terms and definitions

The following terms and definitions apply to this part of GB/T 18318.

3.1

Bending length

The length of a rectangular fabric specimen which is held at one end and

suspended at the other end when it is bent to 7.1° under its own weight.

3.2

Flexural rigidity

The ratio of the minor change of bending moment to the corresponding

change of curvature per unit width of material.

Note: The flexural rigidity may be calculated based on the bending length.

4 Principles

A rectangular specimen is placed on a horizontal platform. The long axis of the

specimen is parallel to the long axis of the platform. Push the specimen along

the long axis of the platform, so that it extends out of the platform and bends

under its own weight. The extended end is suspended. Use a ruler to press

against another part of the specimen which is still on the platform.

When the tip end of the specimen passes through the leading edge of the

platform to an inclined surface at an inclination of 41.5° to the horizontal, the

length of the projection is equal to twice the bending length of the specimen

(see Appendix A), whereby the bending length may be calculated.

5 Instruments

A suitable bending length meter (as shown in Figure 1).

8 Steps

9 Representation of result