Gravel Impact Test and Experimental Exploration of Automobile Body

Gravel Impact Testing and Automotive Body Testing Research

1. Which parts of the car should be gravel impact test

Mainly the front windshield, car headlights, radiators, spoilers (buffers), front of the body and other parts

2. The gravel impact test machine mainly simulates the real car driving conditions. , Some parts of the car body are often hit by heavy objects such as falling materials, road gravel, etc., and the product is damaged. The degree of product damage is determined by the injection angle, injection pressure, number of injections, airflow velocity, specifications and quality of steel shot or gravel, impact duration and test equipment

3 1. Working principleof gravel impact testing machine: a certain weight of gravel is returned to the feeder by vibration. Since the high-velocity airflow in the lower part of the distributor moves at high speed to form a vacuum, the collision medium is sucked into the gun and then thrown towards the test sample by the airflow. jet air. Once the media reaches the test target, it falls into the grain collection bin. The testing machine makes a large number of steel balls or sharp-edged gravel strike the sample surface in a short time, and the whole test is carried out under controllable temperature. After impact, use tape to remove the loose coating to expose the remaining marks of the stone impact points on the specimen. The degree of damage of the sample is analyzed to determine its resistance to stone impact

4. Meet the test standard:

5. ISO 20567 --1 “Determination of stone chip resistance of paint and varnish coatings Part 1: Multiple impact test”

6. SAE J400 “Testing Automotive Surface Coatings for Gravel Resistance

7. ASTM D3170 Coating Resistance to Cracking

8.Standard VDA test

Gravel impact tester as surface coating for automotive materials For the impact resistance test of materials, SAE J400 stipulates the test of impact on sand and gravel (gravel) for the purpose of laboratory testing, and the relevant content is also stipulated in Japan\'s JASO M104. Among these methods, there are various topics such as the shape of flying stones, and methods of Tests and testing machines have been developed to obtain results as close as possible to real driving.

The gravel impact test refers to:

Thegravel and pebbles falling on the road are crushed by driving car tires. in front of flying stones, gravel, etc. who flew up fell from the loading platform to the ground. The small stones flew backwards and met the speed of the car in front of them. Such a collision damaged the components located in the front of the car.

Even if the road surface is relatively good like a freeway, the car in front enters the traffic lane from the freeway entrance. Small stones are mixed into the tire grooves. When accelerating, stones will be thrown from the tires and collide with following vehicles. If you\'re unlucky, it could hit the front glass, creating cracks that would block your view and make driving difficult.

Additionally, when it hits a radiator, etc., depending on the depth ofWhen peeling, it passes through the surface treatment and reaches the raw material, causing water leakage. When it reaches the metal part of the body), it will cause corrosion and damage to the metal body.

Automotive and coating manufacturers are committed to developing and researching styles and structures that can reduce collision damage as much as possible, as well as the composition of coating films. .

The contents of the JASO standard test method in the gravel impact test

Introduce the SAE standard, the configuration shown in Figure 2, successful gravel The method of spraying the air gun on the sample is called the Gravelometer.

Gravel, sprayed on the sample placed vertically, judge its quality by indentation.

The size of gravel used in the test is granite (round gravel) with a size of 9mm to 15mm. Under the action ofcompressed air ejected from the injection port, it collides with the specimen with an inclination angle of 200.

In this specification:

The air pressure (jet pressure) to make the stone fly

1 Air pressure: 0.2 ± 0.02Mpa, 20.4 ± 0.03Mpa

Quantity of flying stones (input quantity): 850g (about 250-300 pieces)

Since even recycled stones will be damaged after repeated use, they are deformed and broken, so the stone must be replaced after ten uses.

Number of testing times: 3 times to 5 times

Prev: Standard method for fog testing of automobile parts أداة الاختبار –