Strength analysis of elongated plywood
The strength of elongated plywood is independent of its size. However, considering the practical application, the weight of plywood with the same size gradually decreases with the increase of plywood length.
LVL lengthened plywood
Generally speaking, the bending design values of 5-plywood and 3-plywood are 35N/mm2 and 37N/mm2 respectively.
Let’s take an example for comparison. Have you ever thought about assuming that the load of a 9mm plywood is 50kg, and that two plywood sheets overlap to bear the weight of 100kg?
In addition to overlapping load-bearing capacity, we should also consider the distribution of weight. Generally speaking, after using two plates, the stress condition of the second plate is better than that of the single plate, because the upper plate is distributed, the strength of the lower plate can be exerted, and the force is more distributed around, which reduces the bending moment. It’s logical to say that when two pieces are stacked, the load-bearing capacity will increase seven times as much as before.
Then consider another analysis. If a 1-meter-long LVL plywood bears 50 kilograms, can a 2-meter plywood bear 100 kilograms?
This is obviously not possible, because the longer the plywood is, the easier it will break. Because the longer the plywood is, the greater the moment is, and the greater the tension at the bottom of the plywood. When the tension is greater than the maximum tensile strength that the plywood itself can bear, the plywood will break.
Therefore, thickening can increase the bearing capacity of plywood, and lengthening can reduce the bearing capacity of plywood. This is why the plywood is generally thicker.