Car safety restraint system as one of the most critical parts of the occupant protection, when the vehicle collision to the occupant restraint and avoid the collision when the occupant and the steering wheel and dashboard and other secondary collision or avoid the collision out of the car resulting in death and injury safety device, has always been the host factory and production suppliers attach great importance to the product quality through static and dynamic experiments for test assessment. Among them, static experiments include light, abrasion resistance, tensile strength, static load, etc. Today, we will introduce to you the safety restraint system in the car seat belt webbing static test.

1 safety restraint system common test standard

Safety restraint system standards are often distinguished by adults and children, children to increase the safety seat, seat belt extension belt and other requirements. At the same time each country has correspondingly stipulated their own restraint system test standards.

I. Motor vehicle occupant seat belts, restraint systems, child restraint systems and ISOFIX child restraint systems GB14166-2013.

II. Motor vehicle child occupant restraint system GB 27887-2011.

III. Webbing for passenger restraint devices in automobiles AS/NZS 1753:2015

IV. Seat belts and adult restraint systems ECE 324/Add 15/R16-2021.

V. Seat belts and child restraint systems ECE 324/Add 43/R44-2021.

VI. Seat belt devices FMVSS 49 CFR ch.v 571 209-2021.

2 Related static test methods

This article mainly introduces GB 14166-2013 and FMVSS 49 CFR ch.v 571 209-2021 in seat belt webbing static test.

(A) Pre-treatment of webbing

In order to simulate the actual use scene of seat belt, it is necessary to carry out the tensile load test after processing such as temperature and humidity state, xenon light illumination, sunlight carbon arc, low temperature, high temperature, water immersion treatment and abrasion resistance to the webbing before the test, and the tensile load retention rate should meet the standard requirements. Tensile test is carried out on the electronic tensile testing machine, after removal from the treatment environment to complete the measurement within the specified time.

(B) webbing strength test

From the working principle of the safety belt can be known, when the occupant torso fast forward, the safety belt tied the occupant torso to stop the occupant forward when the webbing will naturally be subject to a huge impulse, this force is the strength of the safety belt, usually with tensile strength to characterize the strength index, also known as tensile strength. Webbing should be sandwiched between the tensile testing machine fixture, loading speed of 100mm/min, fixture between the specimen length of 200mm ± 40mm. stretching webbing until fracture, record the fracture load value. If the webbing sliding or fracture occurs in the fixture within 10mm, the test is considered invalid and should be re-tested on another specimen.

(C) webbing width test

The width of the webbing is divided into two kinds, one is the original width called the free width, the other is the width when the force is called the load width. The webbing will be protected by a huge impulse, if the width of the force webbing becomes too narrow webbing in the protection of the occupant as the pressure on the body of the occupant is too large will also cause a certain injury to the occupant. Therefore, the width of the stress webbing is more important than the width of the free webbing. Load width webbing is measured under a tension value of the webbing, for example, in the GB 14166 standard stipulates that the load in 9800N width shall not be less than 46mm.

(D) webbing elongation test

Webbing in the protection of occupants, will be subject to a huge impulse. According to the principle of action and reaction force, the occupant's torso will also be subject to a force of equal size. This impact force can be adjusted within a certain range by the elongation of the webbing to reduce the risk of occupant injury. Therefore, the assessment index of webbing elongation rate is also very important.

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