Опубликована: 20 окт 2011, 11:23
Yeahh, why are you talking adout subtleties?.So, you should tell about details, and name them. Or, then, you just like a boy, who knows the secret, but nobody can say it. Then I’ll tell it. It is rather simple. The upper beam with a trapezoidal cup reduced drying, and the angles of slope slightly expanded outward, the width of the cup along the beam remains the same. The lower beam is also reduced on the transverse opening angle of the cheek doesn't change on the face of it. The upper beam under its own weight (we will consider the upper timber wall) and the weight of the roof and a snow is placed on the notch of the lower log. How can get it?
The longitudinal groove with a sample of 6% can go onto the lower sliding on its side surfaces or an indentation.
But the protruding ends prevent it, there is no pressure on them by the roof or the snow, there is only a dead weight. Therefore, the "residue" is hem on the bottom or make a higher notch. If you do not do it, you will risk that the ends will be just cracked, because the bowl is cut more than a half.
And now, a mathematical model for an ideal cylinder, made in a graphical editor. I took three cases where are the logs of the same diameter and different. In all cases, with a drying and a shrinkage remain cracks on the web.... They are thin, I don’t argue. But a tangential shrinkage is greater than a radial shrinkage. The angle of the cheeks of lower timber will be slightly wrapped inside, and the cracks will be a little bigger. The tensile strength of wood is 150 kg/cm2. Assume that the contact of beams is 10 * 10 = 100 cm2, then, to happen the irreversible collapse (as it shows the mathematical model) It is needed a force of 15 tons, and it is only for a one corner.
The longitudinal groove with a sample of 6% can go onto the lower sliding on its side surfaces or an indentation.
But the protruding ends prevent it, there is no pressure on them by the roof or the snow, there is only a dead weight. Therefore, the "residue" is hem on the bottom or make a higher notch. If you do not do it, you will risk that the ends will be just cracked, because the bowl is cut more than a half.
And now, a mathematical model for an ideal cylinder, made in a graphical editor. I took three cases where are the logs of the same diameter and different. In all cases, with a drying and a shrinkage remain cracks on the web.... They are thin, I don’t argue. But a tangential shrinkage is greater than a radial shrinkage. The angle of the cheeks of lower timber will be slightly wrapped inside, and the cracks will be a little bigger. The tensile strength of wood is 150 kg/cm2. Assume that the contact of beams is 10 * 10 = 100 cm2, then, to happen the irreversible collapse (as it shows the mathematical model) It is needed a force of 15 tons, and it is only for a one corner.