nWatch the second video in the series here to see an example of a beam element replacing a solid bolt clamping a plate onto another plate that has a threaded hole.nhttps://forum.ansys.com/discussion/1217/bolt-pretension-clamps-two-plates-togethernRead up on Bolted Joint Analysis. nhttps://mechanicalc.com/reference/bolted-joint-analysisnHere is an image from that page:n
The recommendation is that the grip length in the threaded hole is half the minimum of the thickness or the diameter. That would be a good plane to split the threaded hole so you can scope the fixed joint to that short length of the hole rather than the full length of the hole.nIf there are three plates, there are two clearance holes. The bottom plate has the threaded hole. If the center plate clearance hole is nicely centered, the bolt will not touch the center plate. The top and bottom plates will squeeze the center plate.nA pilot hole is the hole size you drill before you run the tap to cut the threads. You will often see the pilot hole diameter in the CAD model. After the threads are cut, it is called a threaded hole.nIf you draw a line body from top to bottom through the two holes to represent a nut and bolt, it will be meshed with Beam181 elements. If the default mesh size is large it is possible to end up with a single element. That will cause the Bolt Pretension Load to fail to be created. Use a Sizing Mesh Control to force 2 beam elements onto one line body.nIf you have three plates with three holes and want a gap between each of them, you could insert a threaded rod and put a nut on each side of each plate to clamp each plate to the threaded rod. Or you could slide a plain rod through the holes and weld each plate to the smooth rod. To model this, you would create a line body across each gap. Use a Fixed Joint from each vertex to each hole. Maybe you would split the face of the hole in the center plate to have two fixed joints, one for the top plate rod, and the other for the bottom plate rod.n
The recommendation is that the grip length in the threaded hole is half the minimum of the thickness or the diameter. That would be a good plane to split the threaded hole so you can scope the fixed joint to that short length of the hole rather than the full length of the hole.nIf there are three plates, there are two clearance holes. The bottom plate has the threaded hole. If the center plate clearance hole is nicely centered, the bolt will not touch the center plate. The top and bottom plates will squeeze the center plate.nA pilot hole is the hole size you drill before you run the tap to cut the threads. You will often see the pilot hole diameter in the CAD model. After the threads are cut, it is called a threaded hole.nIf you draw a line body from top to bottom through the two holes to represent a nut and bolt, it will be meshed with Beam181 elements. If the default mesh size is large it is possible to end up with a single element. That will cause the Bolt Pretension Load to fail to be created. Use a Sizing Mesh Control to force 2 beam elements onto one line body.nIf you have three plates with three holes and want a gap between each of them, you could insert a threaded rod and put a nut on each side of each plate to clamp each plate to the threaded rod. Or you could slide a plain rod through the holes and weld each plate to the smooth rod. To model this, you would create a line body across each gap. Use a Fixed Joint from each vertex to each hole. Maybe you would split the face of the hole in the center plate to have two fixed joints, one for the top plate rod, and the other for the bottom plate rod.n
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