About the overall test method
"National Standard" GB10454-2000 clause 5.5 "Integral Test Method" stipulates that in addition to periodic lifting, there are 5 tests, including drop test, pressure test, orthographic test and tear propagation test. It has been done by the author for many years. The product experiment realized that the overall lifting test that satisfies the safety factor of 5 times can also meet other tests.
In the lifting test, because 5 times the load is the force of all parts of the group at the same time, the force per unit area is 5 times that of the rated load. If this test can be passed, the heights in the drop test and the tipping test are different. When it is 0.8M and 3M, with the rated load in its free fall, the sum of its own weight and gravitational acceleration is much smaller than that of 5 times the load. The force allocated to the components of the entire bag is also much smaller than when the load is 5 times the load and from the inside to the outside, which poses no threat to the product.
The significance of the test is to imitate the actual working state of the product. The chord of the ocean freighter is more than 0.8M or 0.3M higher than the wharf. This kind of test is of little significance. If the bag really falls down during the port hoisting, there are only two possibilities: one is the port operation is wrong, and the other is the product fails the lifting test.
To achieve a safety factor of 5 times, two of the 4 rings or one of the 2 rings must also have a tensile performance of 2.5 times or more of the rated load. During the frontal test, the bag is lying on the ground, and the two or one hoisting rings on the side close to the ground are lifted up with a hook until the bag is lifted off the ground. There will be no problem with the bag. When the bag body is off the ground, due to the inclination of the single-ear lifting, a non-vertical force component will damage the structure of the root of the ring. The magnitude of this force component is related to the inclination of the bag body, and is also related to the inner packing plane and the ring. The relative position of the root sewing is related to the height. Generally, this tearing force is equivalent to 20-25% of gravity, and will not pose a threat to the sling that can withstand the test of 5 times the safety factor.
In tear propagation, if more than 5 times the load is distributed to a certain part of the carrier 10CM force is F, then the rated load is lifted for tear propagation when the force distributed there is 1/5F. The direction of gravity of the bag contents is mainly downward, which has a certain pressure on the sidewall fabric but is relatively small. This pressure is related to the level of the content material, the size of the bag body, and the powder, granular, and Lumpiness is related to density. At the same time, this pressure is affected by the longitudinal and longitudinal directions of the warp and weft yarns, and the end of the knife edge at 45 degrees to the vertical axis of the bag body will generate two component forces to transmit to the flat yarn in the warp and weft direction of the bag body. Through more complicated calculations, the magnitude of these two component forces can be obtained. As part of the overall stress analysis of the FIBC, the tear propagation is more "complicated" to discuss. However, practice has proved that the knife edge will not be at the rated load. extend.
To sum up, the overall test method items are many, the functions cover each other, the inspection is complicated, and they are all important veto items in the standard inspection. There are many whole bag tests, long test cycles, and high test costs. This is no longer suitable for the fast-paced and low-cost characteristics of today's society. The function of simple, clear, and rapid product quality judgment in the contract environment is the direction of current standard development.