画布 1
Engineering mechanics
  Rigid statics
    The same as we learnt in University Physics
      F=0 M=0
    Linear substrate
      basic functions(still or not)
  Deformation statics
    internal force(torque)
      needed to calculate
      result in deformation
        calculate deformation
    internal force type
      stress(应力)
      Shear force（剪力）
    calculate internal force(torque)
      Cross-sectional method
      Key forces(torque) method
      force shift concept
        The main force The main torque
    (micro) the stress state and different shape of things determines different stress
      in every part we have sum of F = 0,sum of M =0,then we can solve the needed sigma and tau
        the same as the tau
        then we solve them and get
          it's better to calculate during exam i think to avoid remember errors
        find the max
          when
            then
        find the max
          when
            then
            besides those two square has 45degree angle
    (micro)the relationship between force(torque) and deformation
        but to make more clear
    relationship between (micro & macro)
      remember the A and sigma's direction
      The twist of the cylinder(geography according to theory)
      bent of the plane of the beam(geography according to theory)
        (determines the force distribution)(and above ones has uniform distribution)
      bent of the plane of the beam(position defines)
    (macro)the relationship between force(torque) and deformation(can be proved by equations above)
      The stretching and compression of the bar
      The twist of the cylinder
        T is the twist torque
          where Ip
      The bent of the plane of the beam
    (macro) the relationship between ρ & y & θ in The bent of the plane of the beam
      relationship between rho and y
      Boundary conditions
        y=0 Secure the hinged mount
        y=0 y'=0 fixed end
        free end M=0
    (micro) the Strain Energy
      (macro)
      (micro) add three all
        add three all and get
        vv is the energy by changing the Voltage
          calculate by three equal stress(sigma1+sigma2+sigma3)/3
          v_d=v_e-v_V
  Engineering considerations
    materials
      enough
    Strength conditions
      make sure every where
        stretch
        shear
        bearing
    Complex Strength Conditions
      1. Maximum pull stress
      2. Maximum strain
      3. Maximum swear stress
      4. Maximum distortion energy