## Dynamics

Dynamics comprises kinetics and kinematics. In practice, the difference between kinematics and kinetics is the way of looking at the same machine or component. Kinematic questions only consider the geometry of the motion. Kinetics also takes into account the cause of the motion.

The aim of dynamics is to calculate the stress and strain on components or systems in order to be able to design them.

Various movements are displayed graphically and studied using kinematic models.

Conversion of rotary motion into oscillating motion

##### Learning objectives/experiments

- crank mechanism with fixed and oscillating cylinder

Conversion of a uniform rotary motion into a pure harmonic reciprocating motion

##### Learning objectives/experiments

- conversion of a uniform rotary motion into a purely harmonic reciprocating motion
- influence of crank length and input angle on the output stroke
- recording the transmission function of a crank slider

Conversion of rotary motion into oscillating motion

##### Learning objectives/experiments

- investigation of the mechanical relationships on the four-joint link
- investigation of the principle of the crank-rocker mechanism, double rocker mechanism and double crank
- verification of the Grashof condition by varying the crank radius, oscillation radius and coupling length

Uneven reciprocating motion with slow feed and quick return

##### Learning objectives/experiments

- investigation of a revolving crank slider
- influence of crank length and input angle on the output stroke
- recording the transmission function of a revolving crank slider

Phenomenon of the gimbal error in Hooke's couplings and how to avoid it

##### Learning objectives/experiments

- representation of the non-uniform transmission of a universal joint
- determine the gimbal error
- how the arrangement of the universal joints and the deflection angle affect the gimbal error

Determining the lead angle of a steering trapezoid

##### Learning objectives/experiments

- verifying Ackermann’s steering principle
- calculate the wheelbase
- determine the lead angle and the steering error

Investigation of transmission ratios on spur gear units

##### Learning objectives/experiments

- investigation of single-stage or multistage spur gears
- investigation of planetary gears
- determine the transmission ratio

Kinetics studies movements under the influence of forces. The cause of the movement is included in the consideration.

Moments of inertia of different mass arrangements and bodies

##### Learning objectives/experiments

- investigation of the inertia of rigid bodies in rotational motion
- determine mass moments of inertia of different, regularly shaped bodies
- investigation of the mass moment of inertia as a function of the radius

Determining moment of inertia on rotating masses by rolling down an inclined plane and by performing a pendulum test

##### Learning objectives/experiments

- proof of the law of falling bodies on the inclined plane
- influence of the mass of a body on its acceleration
- determine the mass moment of inertia by rolling experiment and pendulum experiment
- Steiner’s theorem

Experimental determination of the moment of mass inertia of a flywheel

##### Learning objectives/experiments

- determine the mass moment of inertia by experiment
- dynamic fundamental law of rotational movement

Investigation of the dynamics of rotation of one-, two- and three-stage spur gear units

##### Learning objectives/experiments

- determining the angular acceleration on gears
- determining the mass moment of inertia of the gear
- determining the friction
- determining the gear efficiency

Investigation of rotational dynamics of a two-stage epicyclic gear with three planetary gears each

##### Learning objectives/experiments

- determine the transmission ratio for a locked gear
- measure transmitted forces for a locked gear
- gear acceleration under constant driving torque
- influence of the transmission ratio
- determine reduced mass moment of inertia

….

Experimental units for the investigation of the laws of rotating masses.

Laws on the behaviour of centrifugal forces on rotating masses

##### Learning objectives/experiments

- investigation of the centrifugal force as a function of
- the speed
- the size of the rotating mass
- the rotation radius

Demonstration of the coriolis force in rotating reference systems

##### Learning objectives/experiments

- inertial or apparent force
- interference of a rotational movement on a translational movement
- visualisation of the Coriolis force effect

Experimental verification of the laws of gyroscopes

##### Learning objectives/experiments

- experimental verification of the gyroscopic laws
- familiarisation with the three gyro axes
- calculation of gyroscopic moments
- study the effect of precession

Characteristic curves of different centrifugal force governors

##### Learning objectives/experiments

- kinetics and kinematics of the following centrifugal systems
- Porter governor
- Proell governor
- Hartnell governor

- adjustment of centrifugal governors

….

Vibration is the process occurring when a physical quantity periodically changes depending on time. This is associated with a conversion of energy from one form to another. In the case of mechanical vibrations, periodic potential energy is converted into kinetic energy and the reverse.

Comparison of physical and mathematical pendulum

##### Learning objectives/experiments

- oscillation period of gravity and rod pendulum
- determine centre of gravity on the rod pendulum
- reduced pendulum length and centre of inertia of the rod pendulum

Moments of inertia of different bodies in a rotary pendulum experiment

##### Learning objectives/experiments

- influence of thread length on the oscillation period
- determine the mass moment of inertia

Determination of the oscillation period depending on torsion wire length, diameter and rotating mass

##### Learning objectives/experiments

- determine the oscillation period as a function of
- the length of the torsion bar
- the diameter of the torsion bar
- the rotating mass and its shape

Investigation of vibrations on a spiral spring rotating mass system

##### Learning objectives/experiments

- determine the rigidity of a helical spring
- determine the natural frequency of a spring-mass system
- investigate the effect of mass and mass distribution

Experiments on damping, resonance and absorber effects in forced vibrations

##### Learning objectives/experiments

- experiments with pendulums
- Kater’s pendulum
- reduced pendulum length
- spring-mass system

- bar-type oscillator

….

Measurement and illustration of frequency and phase response

##### Learning objectives/experiments

- supported experiments with TM 150
- natural vibration of a bar-type oscillator
- damped vibration of a bar-type oscillator
- forced vibration of a bar-type oscillator (damped and undamped resonance)
- frequency and period time measurements

….

Influence of mass, torsional rigidity and damping on the behaviour of a rotary oscillator. Vibrations are recorded on the TM 150/TM 155 recorder.

##### Learning objectives/experiments

- natural frequency of a rotary oscillator
- influence of torsional stiffness, mass and damping

Investigation of the free vibration of a bar and using the Rayleigh method to evaluate the natural frequency of a bar

##### Learning objectives/experiments

- free vibration in a vertical and horizontal bending beam
- determine the natural frequency according to Rayleigh
- how clamping length and mass affect the natural frequency