forked from 1b-agent/fieldcraft-upstream
jyvikoandClaude Opus 5.5
a91ac5baf9
An oracle case of a block pressed on another and slid with static and kinetic coefficients (mu_k N carried once slipping), and the docs of the friction formulation; ROADMAP M7 and parity updated. Co-Authored-By: Claude Opus 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01UhhZMBTviDQxZvwnyP89fo
61 lines
1.8 KiB
JSON
61 lines
1.8 KiB
JSON
{
|
||
"title": "Coulomb friction: a block pressed on another and slid (implicit mortar contact)",
|
||
"kind": "theory",
|
||
"source": "Coulomb's law of dry friction: a sliding interface carries μ_k times the normal force against the slip (C. A. Coulomb, Théorie des machines simples, Mém. Math. Phys. Acad. Sci. 10:161–332, 1785; P. Wriggers, Computational Contact Mechanics, 2nd ed., Springer 2006, §5.2)",
|
||
"quantities": [
|
||
{
|
||
"id": "kinetic",
|
||
"quantity": "the tangential over the normal force across the sliding interface",
|
||
"measure": {
|
||
"from": "slide",
|
||
"pointer": "/contacts/0/force/0",
|
||
"over": {
|
||
"from": "slide",
|
||
"pointer": "/contacts/0/force/2",
|
||
"scale": -1.0
|
||
}
|
||
},
|
||
"value": 0.2,
|
||
"tolerance": {
|
||
"relative": 0.001
|
||
},
|
||
"reason": "once the interface slips its friction is μ_k N exactly (the return map puts every slipping node's traction on the cone); the force opposes the upper block's motion"
|
||
},
|
||
{
|
||
"id": "balance",
|
||
"quantity": "the tangential contact force on the upper block over the sideways reaction at its top (they balance)",
|
||
"measure": {
|
||
"from": "slide",
|
||
"pointer": "/contacts/0/force/0",
|
||
"over": {
|
||
"command": "results.reactions",
|
||
"params": {
|
||
"step": "Slide",
|
||
"sets": [
|
||
"top"
|
||
]
|
||
},
|
||
"pointer": "/sets/0/force/0"
|
||
}
|
||
},
|
||
"value": -1.0,
|
||
"tolerance": {
|
||
"relative": 1e-06
|
||
},
|
||
"reason": "the friction carries the whole sideways load"
|
||
},
|
||
{
|
||
"id": "slipping",
|
||
"quantity": "the secondary nodes that slip (all 9)",
|
||
"measure": {
|
||
"from": "slide",
|
||
"pointer": "/contacts/0/slipping_nodes"
|
||
},
|
||
"value": 9.0,
|
||
"tolerance": {
|
||
"exact": true
|
||
},
|
||
"reason": "a sideways demand far beyond μ N slips the whole interface"
|
||
}
|
||
]
|
||
} |