View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0003352 | OpenFOAM | Contribution | public | 2019-09-19 12:17 | 2019-09-30 14:32 |
| Reporter | handrake0724 | Assigned To | henry | ||
| Priority | normal | Severity | minor | Reproducibility | have not tried |
| Status | resolved | Resolution | fixed | ||
| Product Version | dev | ||||
| Summary | 0003352: support slacked spring of linearSpring restraint | ||||
| Description | when simulating floating structures with soft mooring system with linear spring, spring is slacked instead of making restoring force. I think this feature might be useful to someone like me in offshore field. I made a patch to linearSpring class please review if it is useful. | ||||
| Tags | No tags attached. | ||||
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patch.diff (2,159 bytes)
diff --git a/src/rigidBodyDynamics/restraints/linearSpring/linearSpring.C b/src/rigidBodyDynamics/restraints/linearSpring/linearSpring.C
index dc0a1cdfe..9d131e67b 100644
--- a/src/rigidBodyDynamics/restraints/linearSpring/linearSpring.C
+++ b/src/rigidBodyDynamics/restraints/linearSpring/linearSpring.C
@@ -90,7 +90,9 @@ void Foam::RBD::restraints::linearSpring::restrain
// Force and moment on the master body including optional damping
vector force
(
- (-stiffness_*(magR - restLength_) - damping_*(r & v))*r
+ (allowSlack_ && magR < restLength_)?
+ (- damping_*(r & v))*r
+ : (-stiffness_*(magR - restLength_) - damping_*(r & v))*r
);
vector moment(attachmentPt ^ force);
@@ -100,6 +102,7 @@ void Foam::RBD::restraints::linearSpring::restrain
Info<< " attachmentPt " << attachmentPt
<< " attachmentPt - anchor " << r*magR
<< " spring length " << magR
+ << " allow slack " << allowSlack_
<< " force " << force
<< " moment " << moment
<< endl;
@@ -122,6 +125,7 @@ bool Foam::RBD::restraints::linearSpring::read
coeffs_.lookup("stiffness") >> stiffness_;
coeffs_.lookup("damping") >> damping_;
coeffs_.lookup("restLength") >> restLength_;
+ coeffs_.lookupOrDefault<bool>("allowSlack", false) >> allowSlack_;
return true;
}
@@ -143,6 +147,8 @@ void Foam::RBD::restraints::linearSpring::write
writeEntry(os, "damping", damping_);
writeEntry(os, "restLength", restLength_);
+
+ writeEntry(os, "allowSlack", allowSlack_);
}
diff --git a/src/rigidBodyDynamics/restraints/linearSpring/linearSpring.H b/src/rigidBodyDynamics/restraints/linearSpring/linearSpring.H
index 7f9ddd6fa..74ebdbfb4 100644
--- a/src/rigidBodyDynamics/restraints/linearSpring/linearSpring.H
+++ b/src/rigidBodyDynamics/restraints/linearSpring/linearSpring.H
@@ -72,6 +72,8 @@ class linearSpring
//- Rest length - length of spring when no forces are applied to it
scalar restLength_;
+ //- no restraint when line is shorter than restLength
+ bool allowSlack_;
public:
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Thanks for the contribution. Resolved in OpenFOAM-dev by commit f1b975bbb13b545115b5ed0b74caba5b0ae4e743 |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2019-09-19 12:17 | handrake0724 | New Issue | |
| 2019-09-19 12:17 | handrake0724 | File Added: patch.diff | |
| 2019-09-30 14:32 | henry | Assigned To | => henry |
| 2019-09-30 14:32 | henry | Status | new => resolved |
| 2019-09-30 14:32 | henry | Resolution | open => fixed |
| 2019-09-30 14:32 | henry | Note Added: 0010782 |
