GB/T 3903.25-2021

Footwear—Test methods for whole shoe—Heel attachment (English Version)

Standard No.

GB/T 3903.25-2021

Language

Chinese, Available in English version

Release Date

2021

Published By

General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China

Latest

GB/T 3903.25-2021

Replace

GB/T 3903.25-2008

Scope

This part of GB/T 3903 specifies the method for the determination of the heel bond strength of footwear, which can obtain three relevant wearing properties; - the hardness of the rear part of the shoe during normal walking; permanent deformation of the rear of the shoe; — the force required to separate the heel. This section applies to women's shoes with medium and high heels.

Introduction

Core changes in the standard revision

Technical elements	2008 version	2021 version	Impact of changes
Definition of terms	Hardness	Rigidity	More accurately reflect the mechanical properties of materials
Test equipment	Single fixture	Coarse and fine classification fixtures	Improve test adaptability
Calculation formula	None	Added rigidity rate/deformation rate	Quantitative evaluation indicators

---

Analysis of key test methods

1. Sample preparation requirements

The standard stipulates that the waist reinforcement material must be retained, and the front upper must be cut flush with the insole. For special heels, a 6-7mm positioning hole must be drilled in advance, and the center of the hole is 10mm from the heel opening and the junction of the heel surface.

2. Test three core parameters

• Rigidity test: deformation under 200N tension, reflecting the support for daily wear
• Permanent deformation: irreversible deformation after 400N cyclic load
• Separation strength: record the maximum destructive force value and failure mode

---

Technology evolution analysis

The 2021 version is mainly revised with reference to ISO22650:2018, with emphasis on strengthening:

1. Introducing the deformation rate calculation formula: Rigidity rate = (rigidity/heel height) × 100%
2. Refining the fixture system: distinguishing between thick heel fixture (G-bar structure) and heel height class='instrument'>Thin heel clamp (U-shaped clamp)
3. Improve the test report: it is mandatory to mark the standard number and detailed sample information

---

Laboratory implementation recommendations

Key points for equipment selection

The tensile testing machine must meet ISO75001 B-level accuracy. It is recommended to choose a low inertia force measurement system, and the moving speed must be strictly controlled at 100±10mm/min.

Common Problem Solving

When the maximum separation force cannot be measured due to deformation of the shank, it is recommended to:

• Record the permanent deformation at 400N
• Indicate the "1000N not separated" state in the test report
• Check the centering of the fixture to avoid lateral force interference

---

Standard Application Case

The test of a certain brand of 10cm stiletto heel women's shoes showed:

• Rigidity rate 8.5% (better than the industry average of 5%)
• Permanent deformation rate 3.2mm
• Bonding strength reached 680N (adhesive failure)

This standard verifies that its heel structure design meets the high-intensity wearing requirements.

GB/T 3903.25-2021 Referenced Document

• ISO 7500-1 Metallic materials - Calibration and verification of static uniaxial testing machines - Part 1: Tension/compression testing machines - Calibration and verification of the force-measuring system

GB/T 3903.25-2021 history

• 2021 GB/T 3903.25-2021 Footwear—Test methods for whole shoe—Heel attachment
• 2008 GB/T 3903.25-2008 Footwear.Test methods for whole shoe.Heel attachment

GB/T 3903.25-2021 -All Parts