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API
4.2
For MATLAB, Python, Java, and C++ users
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API
4.2
For MATLAB, Python, Java, and C++ users
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This class implements a nonlinear spring ligament model introduced by Blankevoort et al. (1991) [1] and further described in Smith et al. (2016) [2]. More...
Inheritance diagram for OpenSim::Blankevoort1991Ligament:Static Public Member Functions | |
Auto-generated functions | |
| static Blankevoort1991Ligament * | safeDownCast (OpenSim::Object *obj) |
| For use in MATLAB and Python to access the concrete class. More... | |
| Static Public Member Functions inherited from OpenSim::Force | |
| static Force * | safeDownCast (OpenSim::Object *obj) |
| For use in MATLAB and Python to access the concrete class. More... | |
| static const std::string & | getClassName () |
| This returns "Force" More... | |
| Static Public Member Functions inherited from OpenSim::ModelComponent | |
| static ModelComponent * | safeDownCast (OpenSim::Object *obj) |
| For use in MATLAB and Python to access the concrete class. More... | |
| static const std::string & | getClassName () |
| This returns "ModelComponent" More... | |
| Static Public Member Functions inherited from OpenSim::Component | |
| static Component * | safeDownCast (OpenSim::Object *obj) |
| For use in MATLAB and Python to access the concrete class. More... | |
| static const std::string & | getClassName () |
| This returns "Component" More... | |
| Static Public Member Functions inherited from OpenSim::Object | |
| static void | registerType (const Object &defaultObject) |
| Register an instance of a class; if the class is already registered it will be replaced. More... | |
| static void | renameType (const std::string &oldTypeName, const std::string &newTypeName) |
| Support versioning by associating the current Object type with an old name. More... | |
| static const Object * | getDefaultInstanceOfType (const std::string &concreteClassName) |
| Return a pointer to the default instance of the registered (concrete) Object whose class name is given, or NULL if the type is not registered. More... | |
| template<class T > | |
| static bool | isObjectTypeDerivedFrom (const std::string &concreteClassName) |
| Return true if the given concrete object type represents a subclass of the template object type T, and thus could be referenced with a T*. More... | |
| static Object * | newInstanceOfType (const std::string &concreteClassName) |
| Create a new instance of the concrete Object type whose class name is given as concreteClassName. More... | |
| static void | getRegisteredTypenames (Array< std::string > &typeNames) |
| Retrieve all the typenames registered so far. More... | |
| template<class T > | |
| static void | getRegisteredObjectsOfGivenType (ArrayPtrs< T > &rArray) |
| Return an array of pointers to the default instances of all registered (concrete) Object types that derive from a given Object-derived type that does not have to be concrete. More... | |
| static bool | PrintPropertyInfo (std::ostream &os, const std::string &classNameDotPropertyName, bool printFlagInfo=true) |
| Dump formatted property information to a given output stream, useful for creating a "help" facility for registered objects. More... | |
| static bool | PrintPropertyInfo (std::ostream &os, const std::string &className, const std::string &propertyName, bool printFlagInfo=true) |
| Same as the other signature but the class name and property name are provided as two separate strings. More... | |
| static Object * | makeObjectFromFile (const std::string &fileName) |
| Create an OpenSim object whose type is based on the tag at the root node of the XML file passed in. More... | |
| static const std::string & | getClassName () |
| Return the name of this class as a string; i.e., "Object". More... | |
| static void | setSerializeAllDefaults (bool shouldSerializeDefaults) |
| Static function to control whether all registered objects and their properties are written to the defaults section of output files rather than only those values for which the default was explicitly overwritten when read in from an input file or set programmatically. More... | |
| static bool | getSerializeAllDefaults () |
| Report the value of the "serialize all defaults" flag. More... | |
| static bool | isKindOf (const char *type) |
| Returns true if the passed-in string is "Object"; each Object-derived class defines a method of this name for its own class name. More... | |
| static void | setDebugLevel (int newLevel) |
| Set the amount of logging output. More... | |
| static int | getDebugLevel () |
| Get the current setting of debug level. More... | |
| static Object * | SafeCopy (const Object *aObject) |
| Use the clone() method to duplicate the given object unless the pointer is null in which case null is returned. More... | |
| static void | RegisterType (const Object &defaultObject) |
| OBSOLETE alternate name for registerType(). More... | |
| static void | RenameType (const std::string &oldName, const std::string &newName) |
| OBSOLETE alternate name for renameType(). More... | |
Auto-generated functions <br> | |
| static const std::string & | getClassName () |
| This returns "Blankevoort1991Ligament" More... | |
| Blankevoort1991Ligament * | clone () const override |
| Create a new heap-allocated copy of the concrete object to which this Object refers. More... | |
| const std::string & | getConcreteClassName () const override |
| Returns the class name of the concrete Object-derived class of the actual object referenced by this Object, as a string. More... | |
Additional Inherited Members | |
| Public Member Functions inherited from OpenSim::Force | |
| Public Member Functions inherited from OpenSim::ModelComponent | |
| ModelComponent () | |
| Default constructor. More... | |
| ModelComponent (const std::string &aFileName, bool aUpdateFromXMLNode=true) | |
| Construct ModelComponent from an XML file. More... | |
| ModelComponent (SimTK::Xml::Element &aNode) | |
| Construct ModelComponent from a specific node in an XML document. More... | |
| virtual | ~ModelComponent () |
| Destructor is virtual to allow concrete model component cleanup. More... | |
| void | connectToModel (Model &model) |
| Connect this ModelComponent to its aggregate- a Model. More... | |
| const Model & | getModel () const |
| Get a const reference to the Model this component is part of. More... | |
| Model & | updModel () |
| Get a modifiable reference to the Model this component is part of. More... | |
| bool | hasModel () const |
| Does this ModelComponent have a Model associated with it? More... | |
| void | preScale (const SimTK::State &s, const ScaleSet &scaleSet) |
| Perform any computations that must occur before ModelComponent::scale() is invoked on all ModelComponents in the Model. More... | |
| void | scale (const SimTK::State &s, const ScaleSet &scaleSet) |
| Scale the ModelComponent. More... | |
| void | postScale (const SimTK::State &s, const ScaleSet &scaleSet) |
| Perform any computations that must occur after ModelComponent::scale() has been invoked on all ModelComponents in the Model. More... | |
| Public Member Functions inherited from OpenSim::Component | |
| Public Member Functions inherited from OpenSim::Object | |
| virtual | ~Object () |
| Virtual destructor for cleanup. More... | |
| bool | isEqualTo (const Object &aObject) const |
| Equality operator wrapper for use from languages not supporting operator overloading. More... | |
| Object & | operator= (const Object &aObject) |
| Copy assignment copies he base class fields, including the properties. More... | |
| virtual bool | operator== (const Object &aObject) const |
| Determine if two objects are equal. More... | |
| virtual bool | operator< (const Object &aObject) const |
| Provide an ordering for objects so they can be put in sorted containers. More... | |
| void | setName (const std::string &name) |
| Set the name of the Object. More... | |
| const std::string & | getName () const |
| Get the name of this Object. More... | |
| void | setDescription (const std::string &description) |
| Set description, a one-liner summary. More... | |
| const std::string & | getDescription () const |
| Get description, a one-liner summary. More... | |
| const std::string & | getAuthors () const |
| Get Authors of this Object. More... | |
| void | setAuthors (const std::string &authors) |
| Set Authors of this object. More... | |
| const std::string & | getReferences () const |
| Get references or publications to cite if using this object. More... | |
| void | setReferences (const std::string &references) |
| Set references or publications to cite if using this object. More... | |
| int | getNumProperties () const |
| Determine how many properties are stored with this Object. More... | |
| const AbstractProperty & | getPropertyByIndex (int propertyIndex) const |
| Get a const reference to a property by its index number, returned as an AbstractProperty. More... | |
| AbstractProperty & | updPropertyByIndex (int propertyIndex) |
| Get a writable reference to a property by its index number, returned as an AbstractProperty. More... | |
| bool | hasProperty (const std::string &name) const |
| Return true if this Object has a property of any type with the given name, which must not be empty. More... | |
| const AbstractProperty & | getPropertyByName (const std::string &name) const |
| Get a const reference to a property by its name, returned as an AbstractProperty. More... | |
| AbstractProperty & | updPropertyByName (const std::string &name) |
| Get a writable reference to a property by its name, returned as an AbstractProperty. More... | |
| template<class T > | |
| bool | hasProperty () const |
| Return true if this Object contains an unnamed, one-object property that contains objects of the given template type T. More... | |
| template<class T > | |
| const Property< T > & | getProperty (const PropertyIndex &index) const |
| Get property of known type Property<T> as a const reference; the property must be present and have the right type. More... | |
| template<class T > | |
| Property< T > & | updProperty (const PropertyIndex &index) |
| Get property of known type Property<T> as a writable reference; the property must be present and have the right type. More... | |
| bool | isObjectUpToDateWithProperties () const |
Returns true if no property's value has changed since the last time setObjectIsUpToDateWithProperties() was called. More... | |
| void | readObjectFromXMLNodeOrFile (SimTK::Xml::Element &objectElement, int versionNumber) |
| We're given an XML element from which we are to populate this Object. More... | |
| void | updateXMLNode (SimTK::Xml::Element &parent, const AbstractProperty *prop=nullptr) const |
| Serialize this object into the XML node that represents it. More... | |
| bool | getInlined () const |
| Inlined means an in-memory Object that is not associated with an XMLDocument. More... | |
| void | setInlined (bool aInlined, const std::string &aFileName="") |
| Mark this as inlined or not and optionally provide a file name to associate with the new XMLDocument for the non-inline case. More... | |
| std::string | getDocumentFileName () const |
| If there is a document associated with this object then return the file name maintained by the document. More... | |
| int | getDocumentFileVersion () const |
| If there is a document associated with this object then return its version number. More... | |
| void | setAllPropertiesUseDefault (bool aUseDefault) |
| bool | print (const std::string &fileName) const |
| Write this Object into an XML file of the given name; conventionally the suffix to use is ".osim". More... | |
| std::string | dump () const |
| dump the XML representation of this Object into an std::string and return it. More... | |
| virtual bool | isA (const char *type) const |
| The default implementation returns true only if the supplied string is "Object"; each Object-derived class overrides this to match its own class name. More... | |
| const std::string & | toString () const |
| Wrapper to be used on Java side to display objects in tree; this returns just the object's name. More... | |
| PropertySet & | getPropertySet () |
| OBSOLETE: Get a reference to the PropertySet maintained by the Object. More... | |
| const PropertySet & | getPropertySet () const |
This class implements a nonlinear spring ligament model introduced by Blankevoort et al. (1991) [1] and further described in Smith et al. (2016) [2].
This model is partially based on the formulation orginally proposed by Wismans et al. (1980) [3]. The ligament is represented as a passive spring with the force-strain relationship described by a quadratic "toe" region at low strains and a linear region at high strains. The toe region represents the uncrimping and alignment of collagen fibers and the linear region represents the subsequent stretching of the aligned fibers. The ligament model also includes a damping force that is only applied if the ligament is stretched beyond the slack length and if the ligament is lengthening. The length of the ligament is \( l \).
Governing Equations
Spring Force:
\[ F_{\mathrm{spring}} = \begin{Bmatrix} 0 & \epsilon < 0 \\ \frac{1}{2\epsilon_t }k\epsilon^2 & 0 \leq \epsilon \leq \epsilon_t \\ k(\epsilon - \frac{\epsilon_t}{2})& \epsilon > \epsilon_t \end{Bmatrix} \]
Damping Force:
\[ F_{\mathrm{damping}} = \begin{Bmatrix} c\cdot \dot{\epsilon} & \epsilon > 0 \: and \: \dot{\epsilon} > 0 \\ 0 & otherwise \end{Bmatrix} \]
Total Force:
\[ F_{\mathrm{total}} = F_{\mathrm{spring}} + F_{\mathrm{damping}} \]
This Force component has the following properties:
The Blankevoort1991Ligament implementation is intended to be compatible with common methods in the literature for parameterizing ligament properties. The zero-load length of the ligament is parameterized by the slack_length property, which can be set directly, in meters, using set_slack_length(), or using setSlackLengthFromReferenceStrain() and setSlackLengthFromReferenceForce(). Here, reference strain and reference force are the strain or force in the ligament at a reference pose (state). If you want to compute the strain or force of the ligament in a given pose (state), you can use the getStrain() and getForce() methods. The linear_stiffness property has units of force/strain (newton) but can be set and obtained in units of force/length (newton/meter) using setLinearStiffnessForcePerLength() and getLinearStiffnessForcePerLength().
When scaling a model (using the ScaleTool) that contains a Blankevoort1991Ligament, the slack_length property is scaled by the ratio of the entire GeometryPath length in the default model pose before and after scaling the bone geometries. This ensures that the strain in the ligament in the default pose is equivilent before and after scaling. Thus, it is important to consider the order of scaling the model and setting the slack_length property for your specific application. The linear_stiffness property is not affected by scaling the model.
[1] Blankevoort, L. and Huiskes, R., (1991). Ligament-bone interaction in a three-dimensional model of the knee. J Biomech Eng, 113(3), 263-269
[2] Smith, C.R., Lenhart, R.L., Kaiser, J., Vignos, M.F. and Thelen, D.G., (2016). Influence of ligament properties on tibiofemoral mechanics in walking. J Knee Surg, 29(02), 99-106.
[3] Wismans, J.A.C., Veldpaus, F., Janssen, J., Huson, A. and Struben, P., (1980). A three-dimensional mathematical model of the knee-joint. J Biomech, 13(8), 677-685.
[4] Marra, M. A., Vanheule, V., Fluit, R., Koopman, B. H., Rasmussen, J., Verdonschot, N., & Andersen, M. S. (2015). A subject-specific musculoskeletal modeling framework to predict in vivo mechanics of total knee arthroplasty. Journal of biomechanical engineering, 137(2), 020904.
[5] Guess, T. M., Razu, S., & Jahandar, H. (2016). Evaluation of knee ligament mechanics using computational models. The journal of knee surgery, 29(02), 126-137.
[6] Li, G., Gil, J., Kanamori, A., & Woo, S. Y. (1999). A validated three-dimensional computational model of a human knee joint. Journal of biomechanical engineering, 121(6), 657-662.
[7] Ristaniemi, A., Stenroth, L., Mikkonen, S., & Korhonen, R. K. (2018). Comparison of elastic, viscoelastic and failure tensile material properties of knee ligaments and patellar tendon. Journal of biomechanics, 79, 31-38.
[8] Weiss, J. A., & Gardiner, J. C. (2001). Computational modeling of ligament mechanics. Critical Reviews in Biomedical Engineering, 29(3).
[9] Martin, R. B., Burr, D. B., Sharkey, N. A., & Fyhrie, D. P. (2015). Mechanical properties of ligament and tendon. In Skeletal Tissue Mechanics (pp. 175-225). Springer, New York, NY.
[10] Pioletti, D. P., Rakotomanana, L. R., Benvenuti, J. F., & Leyvraz, P. F. (1998). Viscoelastic constitutive law in large deformations: application to human knee ligaments and tendons. Journal of biomechanics, 31(8), 753-757.
[11] Pioletti, D. P., Rakotomanana, L. R., & Leyvraz, P. F. (1999). Strain rate effect on the mechanical behavior of the anterior cruciate ligament-bone complex. Medical Engineering & Physics, 21(2), 95-100.
[12] Galbusera, F., Freutel, M., Durselen, L., D'Aiuto, M., Croce, D., Villa, T., Sansone, V. & Innocenti, B. (2014). Material models and properties in the finite element analysis of knee ligaments: a literature review. Frontiers in bioengineering and biotechnology, 2, 54.
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inlineoverridevirtual |
Create a new heap-allocated copy of the concrete object to which this Object refers.
It is up to the caller to delete the returned object when no longer needed. Every concrete object deriving from Object implements this pure virtual method automatically, via the declaration macro it invokes (e.g., OpenSim_DECLARE_CONCRETE_OBJECT()). Note that the concrete class overrides modify the return type to be a pointer to the concrete object; that still overrides the base class method because the return type is covariant with (that is, derives from) Object.
Implements OpenSim::Force.
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inlinestatic |
This returns "Blankevoort1991Ligament"
See getConcreteClassName() if you want the class name of the underlying concrete object instead.
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inlineoverridevirtual |
Returns the class name of the concrete Object-derived class of the actual object referenced by this Object, as a string.
This is the string that is used as the tag for this concrete object in an XML file. Every concrete class derived from Object automatically overrides this method via the declaration macro it uses. See getClassName() to get the class name of the referencing (possibly abstract) class rather than the concrete object.
Implements OpenSim::Force.
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inlinestatic |
For use in MATLAB and Python to access the concrete class.
Example: cObj = Blankevoort1991Ligament.safeDownCast(obj). This is equivalent to dynamic_cast<Blankevoort1991Ligament*>(obj) in C++.
1.9.1 