static analysis

static analysis overview

• how to quantify human activity in motion and at rest

  • through kinetics and kinematics we can understand forces and motion

• with concepts and relationships defined by Newton’s laws we can solve for unknown variables

Newton’s first law - static analysis

• linear: object stay at rest ad an object in motion stays in motion unless acted upon by a NET external force

• angular: body will matiantian constant state of angular motion unless acted on by a net external torque

• NET forcers

  • look at all forces and moments acting on the system

  • sum of zero and system is in state of equilibrium

  • sum other than zero means that the object is in a state of change in motion

    • acceleration

equilibrium

• sum of all forces and moments acting on an object are zero

  • acceleration of zero

  • object in equilibrium

• ∑F=0 and∑M=0 to solve for unknown quantities when an objet is in static equilibrium

• equations are true for all 3 axis dimensions

joint reaction force

• must consider that any applied force will be accompanied by a joint reaction force

• if limb is not in motion then the object is in static equilibrium and the equation is true

  • ∑F = F_applied+F_{joint-reaction}=0

    • applied will b e qual and opposite to reaction force

      • does matter with angualr but not linear

      • would also have an effect on CoM of the limb

• in linear sense regardless of where force is acting the force can be summed together

  • important ot remember where forced acting to be able ot quantify moment caused by the force

implications of force

• need to consider the components of forces must be zero for an object ot be in static equilibrium

  • often have ot colder for joint run forces as they are difficult to measure by the F_applied is much easier to remember

• applied force tends ot cease a irritation about the joint creating a moment that just be countered if the arm is to remain static

importance of statistical analysis

• impossible ot directly measure integral force but abitlyi to solve for static equilibrium problems yields an estimate of their forcers

• for example can see the amount of force required to remain in positions and the stress exerted on these joints

application of static analysis

• ergonomics

• static prosutere

• sports

  • static situations