Python System.update_matrices方法代码示例

# 需要导入模块: from mbwind import System [as 别名]
# 或者: from mbwind.System import update_matrices [as 别名]
    def test_distal_forces_cause_acceleration(self):
        j = FreeJoint('joint')
        b = RigidBody('body', mass=3, inertia=np.diag([7, 7, 7]))
        s = System()
        s.add_leaf(j)
        j.add_leaf(b)
        s.setup()

        # Constant loading
        j.distal_forces = np.array([2, 0, 0, 0, 0, 0])
        s.update_kinematics()
        s.update_matrices()
        s.solve_accelerations()
        s.update_kinematics()
        assert_array_equal(j.ad, [2. / 3, 0, 0, 0, 0, 0])

# 需要导入模块: from mbwind import System [as 别名]
# 或者: from mbwind.System import update_matrices [as 别名]
class TestReactionForcesForCentrifugalForce(unittest.TestCase):
    """
    System
    ------
    A rigid body with offset mass, attached to a spinning hinge.

    Tests
    -----
    Check centrifugal force reaction on hinge is in correct direction.
    """

    mass = 5.0  # kg
    offset = 3.2  # m

    def setUp(self):
        # Rigid body with offset centre of mass
        self.body = RigidBody("body", self.mass, Xc=[self.offset, 0, 0])

        # Hinge with axis along Z axis
        self.hinge = Hinge("hinge", [0, 0, 1])

        # Build system
        self.system = System()
        self.system.add_leaf(self.hinge)
        self.hinge.add_leaf(self.body)
        self.system.setup()
        self.system.update_kinematics()  # Set up nodal values initially
        self.system.update_matrices()

    def test_reactions(self):
        # Set angular acceleration
        w = 5.21  # rad/s
        self.hinge.vstrain[0] = w
        self.system.update_kinematics()  # Update nodal values based on DOFs
        self.system.update_matrices()
        self.system.solve_reactions()  # Solve reactions incl d'Alembert

        # Some parameters
        L = self.offset
        m = self.mass

        # Check reactions at beam root
        Pg = self.system.joint_reactions["ground"]
        P0 = self.system.joint_reactions["node-0"]
        Fx_expected = -m * L * w ** 2
        assert_aae(P0, [Fx_expected, 0, 0, 0, 0, 0])
        assert_aae(Pg, P0)

# 需要导入模块: from mbwind import System [as 别名]
# 或者: from mbwind.System import update_matrices [as 别名]
class hinged_beam_tests(unittest.TestCase):
    density = 5.0
    length = 20.0
    force = 34.2  # N/m
    hinge_torque = 0.0
    free_beam = False

    def setUp(self):
        # FE model for beam
        x = linspace(0, self.length, 20)
        fe = BeamFE(x, density=self.density, EA=0, EIy=1, EIz=0)
        fe.set_boundary_conditions('C', 'F')
        self.beam = ModalElementFromFE('beam', fe, 0)

        # Set loading - in negative Z direction
        load = np.zeros((len(x), 3))
        load[:, 2] = -self.force
        self.beam.loading = load

        # Hinge with axis along Y axis
        self.hinge = Hinge('hinge', [0, 1, 0])
        self.hinge.internal_torque = self.hinge_torque

        # Build system
        self.system = System()
        self.system.add_leaf(self.hinge)
        self.hinge.add_leaf(self.beam)
        self.system.setup()

        if not self.free_beam:
            # Prescribe hinge to be fixed
            self.system.prescribe(self.hinge)

        # Initial calculations
        self.recalc()

    def recalc(self):
        self.system.update_kinematics()    # Set up nodal values initially
        self.system.update_matrices()
        self.system.solve_accelerations()  # Calculate accelerations of DOFs
        self.system.update_kinematics()    # Update nodal values based on DOFs
        self.system.update_matrices()
        self.system.solve_reactions()      # Solve reactions incl d'Alembert

# 需要导入模块: from mbwind import System [as 别名]
# 或者: from mbwind.System import update_matrices [as 别名]
    def test_find_equilibrium(self):
        g = 9.81
        m = 23.1
        k = 45.2
        s = System(gravity=g)
        slider = PrismaticJoint('slider', [0, 0, 1])
        slider.stiffness = k
        body = RigidBody('body', mass=m)
        s.add_leaf(slider)
        slider.add_leaf(body)
        s.setup()

        # Initially position should be zero and acceleration nonzero
        s.solve_accelerations()
        assert_aae(slider.xstrain, 0)
        assert_aae(slider.astrain, -g)

        # At equilibrium, position should be nozero and force on body zero
        s.find_equilibrium()
        s.update_matrices()      # recalculate stiffness force
        s.solve_accelerations()
        assert_aae(slider.xstrain, -m * g / k)
        assert_aae(slider.astrain, 0)

# 需要导入模块: from mbwind import System [as 别名]
# 或者: from mbwind.System import update_matrices [as 别名]
class TestReactionForcesWithRotatedBeam(unittest.TestCase):
    """Intended to check the transformation from blade loading to rotor
    loading in a wind turbine rotor: the loads are applied to the beam
    in the local rotated coordinate system, check they work through to
    the ground reactions correctly.
    """
    force = 24.1
    length = 4.3
    root_length = 0.0

    def setUp(self):
        # FE model for beam - no modes, i.e. rigid
        self.x = x = linspace(0, self.length, 20)
        fe = BeamFE(x, density=2, EA=0, EIy=0, EIz=0)

        # Build the elements
        self.shaft = Hinge('shaft', [1, 0, 0])

        self.roots = []
        self.blades = []
        self.pitch_bearings = []
        for ib in range(1):
            R = rotations(('x', ib*2*pi/3), ('y', -pi/2))
            root_offset = dot(R, [self.root_length, 0, 0])
            root = RigidConnection('root%d' % (ib+1), root_offset, R)
            bearing = Hinge('pitch%d' % (ib+1), [1, 0, 0])
            blade = ModalElementFromFE('blade%d' % (ib+1), fe, 0)

            self.shaft.add_leaf(root)
            root.add_leaf(bearing)
            bearing.add_leaf(blade)

            self.roots.append(root)
            self.blades.append(blade)
            self.pitch_bearings.append(bearing)

        # Build system
        self.system = System()
        self.system.add_leaf(self.shaft)
        self.system.setup()
        self.system.update_kinematics()    # Set up nodal values initially
        self.system.update_matrices()

    def test_reactions(self):
        # Some parameters
        L = self.length
        F = self.length * self.force

        # Set loading - in local z direction
        load = np.zeros((len(self.x), 3))
        load[:, 2] = self.force
        self.blades[0].loading = load
        self.system.update_kinematics()
        self.system.update_matrices()
        self.system.solve_reactions()

        # Check reactions at ground (0, 0, 0)
        P = -self.system.joint_reactions['ground']
        F_expected = [-F, 0, 0]
        M_expected = [0, -F*(L+self.root_length)/2, 0]
        assert_aae(P, np.r_[F_expected, M_expected])

        # Reactions on other side of hinge
        P2 = -self.system.joint_reactions['node-0']
        assert_aae(P, P2)

        # Now set pitch angle to 45deg
        # NB: hinge rotation is opposite to wind turbine pitch convention
        self.pitch_bearings[0].xstrain[0] = -pi / 4
        self.system.update_kinematics()
        self.system.update_matrices()
        self.system.solve_reactions()

        # Check reactions at ground (0, 0, 0)
        P = -self.system.joint_reactions['ground']
        F_expected = [-F/sqrt(2), F/sqrt(2), 0]
        M_expected = [-F/sqrt(2)*L/2, -F/sqrt(2)*L/2, 0]
        assert_aae(P, np.r_[F_expected, M_expected])

        # Reactions on other side of hinge
        P2 = -self.system.joint_reactions['node-0']
        assert_aae(P, P2)