49. Wave energy capture device 1

The identification tag for this tutorial is PDS-ABJ. Pregenerated input files for this tutorial are found in the folder named PDS-ABJ in the provided tutorial input files.

49.1. Tutorial overview

This tutorial covers:

  • Using multiple ABA connections in a chain sequence
  • The revolute ABA joint
alternate text

Fig. 49.1 Wave energy converter

49.2. Initializing the WEC system RigidBody DObjects

  • Create a new project.
  • Create three RigidBody DObjects and call them float0, float1, and float2.

Note

  • The wave energy converter will be comprised of three horizontal cylinder floats of 2 m diameter and 10 m long connected end to end by revolute pin joints.
  • Add a RigidBodyCylinder feature to the library and set the $Diameter property to 2 m and $Length property to 10 m.
  • By design, the WEC cylinder floats will be 50% submerged in calm conditions. Set the $Mass property to 1.6e4 kg. The moment of inertia values are set arbitrarily to 1e4 kgm2. To prevent the cylinders from rolling, set the $CGPosition to have a 1 m offset in the z direction.
  • In order to have the inertia of the cylinders defined about the center of gravity, enable the $DefineInertiaAboutCG property.
  • Add a cylinder to each of the RigidBodies. To make the cylinders lie flat on the water, the feature frame has to be pitched by 90 degrees in the y direction.

49.3. Creating a chain of ABA connections

  • Create an ABA connection and make float0 master of float1.
  • Create a second ABA connection and make float1 master of float2.
  • Change the connection information for both connections to have the $Joint property set to type 1, which creates a revolute joint.
  • Set the $FollowerJointAxis property to 1 for both connections. This sets the revolute axis to the y-axis.
  • In the connection section, change the connection joint reference type property from the default $PrismaticJointLinear to $RevoluteJointAngular and reference the RigidBodyABAConnectionJoint that has been automatically created.
  • In the RigidBodyABAConnectionJoint feature, change the $CJoint property to have a damping of 1e4 N*m*s/deg. This will act as the energy capture from the relative motion of the system.
  • The cylinders are located end-to-end, so in both connections, specify the $MasterConnectionLocation property to have the offset (-5,0,0) m with no rotation, and the $FollowerConnectionLocation property to have the offset (5,0,0) m with no rotation. This places the connection location in between the two cylinders.
  • Set the state for float0 to be at the origin with no velocity or rotation. Set the state for float1 and float2 to have an ABA state with one degree of freedom and a velocity of 0 m/s and a angle of 0 degrees.

49.4. Running the simulation and visualizing in PostPDS

  • Set Airy waves with height of 3 m and a period of 7 seconds.
  • Set the water depth to 50 m.
  • Run the simulation for 60 seconds.
  • Visualize the results in PostPDS.