GB/T 18318.1-2009 English PDF (GBT18318.1-2009)

Delivery: 3 seconds. Download true-PDF + Invoice.
Get QUOTATION in 1-minute: Click GB/T 18318.1-2009
Historical versions: GB/T 18318.1-2009
Preview True-PDF (Reload/Scroll if blank)

GB/T 18318.1-2009: Textiles -- Determination of bending behavior -- Part 1: Incline method
GB/T 18318.1-2009
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 59.080.30
W 04
Replacing GB/T 18318-2001
Textiles - Determination of bending behavior -
Part 1: Incline method
(ISO 9073-7:1995, Textiles - Test methods for nonwovens -
Part 7: Determination of bending length, MOD)
ISSUED ON: SEPTEMBER 30, 2009
IMPLEMENTED ON: MARCH 01, 2010
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of PRC;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3 
1 Scope ... 5 
2 Normative references ... 5 
3 Terms and definitions ... 5 
4 Principles ... 6 
5 Instruments ... 6 
6 Sampling ... 7 
7 Preparation and conditioning of specimen ... 7 
8 Steps ... 8 
9 Representation of result ... 8 
10 Test report ... 9 
Appendix A (Informative) Flexural rigidity, bending length, projection length . 10 
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).
5.1 Horizontal device.
5.2 Platform: The width is (40 ± 2) mm. The length is not less than 250 mm. It
is supported at a height of at least 150 mm above the tabletop. The inclined
surface which passes through the leading edge of the platform is at an angle of
41.5° to the bottom of the horizontal platform. The line connecting the side of
the platform support to the inclined surface is L1 and L2.
Mark D at a position (10 ± 1) mm from the leading edge of the platform.
Note: To avoid adhesion of the specimen, it should coat or cover a layer of
polytetrafluoroethylene (PTFE) on the surface of the platform.
5.3 Steel ruler: The width is (25 ± 1) mm. The length is not less than the length
of platform. The mass is (250 ± 10) g. The scale is millimeter. There is a rubber
layer on the lower surface.
Note: The steel ruler has a thickness of 3.5 mm, which can obtain an accurate
mass.
8 Steps
8.1 According to GB/T 4669 or GB/T 24218.1, determine and calculate the mass
per unit area of the specimen.
8.2 Adjust the level of the instrument. Place the specimen on the platform. Let
one end of the specimen coincide with the leading edge of the platform. Place
the steel ruler on the specimen. The zero point of the steel ruler is aligned with
the mark D on the platform.
At a certain speed, push the steel ruler and the specimen forward, so that the
specimen projects from the leading edge of the platform and bends under its
own weight, until the projected end of the specimen contacts the inclined
surface. Record the scale of the steel ruler corresponding to the mark D as the
projection length of the specimen.
8.3 Repeat 8.2, to test the other side of the same specimen. Repeat on both
sides of the other end of the specimen to carry out test.
Note: Place the instrument to facilitate observation of the zero point on the steel ruler
and the contact of the specimen with the slope, to ensure accurate reading in the
horizontal direction.
9 Representation of result
9.1 Take half of the projected length as the bending length. Record four bending
lengths for each specimen, to calculate the average bending length of each
specimen.
9.2 Respectively, calculate the average bending length C of each specimen in
both directions, in centimeters.
9.3 Use the formula (1) to calculate the flexural rigidity per average unit width
in both directions. Retain three significant digits.
Where:
G - Flexural rigidity per unit width, in milliNewton centimeter (mN·cm);
m - The mass per unit area of the specimen, in grams per square met...