Motion simulation

WHAT IS MOTION SIMULATION ?

Motion simulation provides complete, quantitative information about the kinematics—including position, velocity, and acceleration, and the dynamics—including joint reactions, inertial forces, and power requirements, of all the components of a moving mechanism.

By using Motion simulation, one can find the real-time behaviour of a Mechanism or Machine. It also helps us to find out the trajectories that are formed by the moving elements.

Suppose we made hole and shaft assembly and want to check the clearance between them while in running condition, then with the help of motion simulation, we can easily find out because motion simulation conducts interference checks in real time, and provides the exact spatial and time positions of all mechanism components as well as the exact interfering volumes.

Suppose an engineer is designing an elliptic trammel meant for tracing different ellipses. When he has defined mates in the CAD assembly, he can animate the model to review how the components of the mechanism move (Figure 1). Although assembly animation can show the relative motion of assembly components, the speed of motion is irrelevant and timing is arbitrary. To find velocities, accelerations, joint reactions, power requirements, etc., the designer needs a more powerful tool. This is where motion simulation comes in.

In the case of the elliptic trammel described above, the designer needs only to decide the speed of the motor, the points to be traced, and the motion results he wishes to see. The program does everything else automatically, without the user’s intervention. The motion simulation program uses material properties from the CAD parts to define inertial properties of mechanism components, and translates CAD assembly mating conditions into kinematic joints. It then automatically formulates equations that describe the mechanism motion.

Unlike flexible structures studied with FEA, mechanisms are represented as assemblies of rigid components and have few degrees of freedom. A numerical solver solves the equations of motion very quickly, and results include full information about displacements, velocities, accelerations, joint reactions, and inertial loads of all the mechanism components, as well as the power necessary to sustain the motion (Figure 2).

Hope you find this post interesting and helps you to understand motion simulation. In next post, I will provide examples of motion simulation in solidworks.

MOTION ANALYSIS

MOTION ANALYSIS

Motion Analysis is used to analyse a assembly or part when it is in motion. It helps to understand what kind of output motion is going to be given by the assembly. It also enable us to check whether the output given by the assembly is correct or not and if not correct, then where amendment is required. 

Motion analysis also gives the advantage of analysing a part dynamically i.e what kind of forces are going to act when the given part is in motion.

Solidworks motion simulation contains various inputs parameters and output parameters.

Motion Analysis can be found only in assembly files. It has several features related to the motion of an assembly file. 

Features of Motion Study:-

Motion Study Tab – This tab allows us to analyze the motion study of the assembly file.

Motion Manager Tree – This contains all the parts, sub-assemblies, mates, and the simulation elements.

Calculate – This button allows calculating the motions of the assembly and helps to update after changes made.

Play – This button allows us to play the animation to see how it works after calculating the motion.

Playback Speed – This helps to reduce or increase the speed of the animation.

Save Animation – This button helps to save the animation as a video.

Motor – This allows simulating a motor or giving a torque to the animation such as at pin connections.

Spring – This allows simulating a spring in motion where you can edit the spring constant and length.

Force – This allows simulating forces on any part of an object.

Contact – This allows stopping the interference between solid objects and adjusting the friction between objects when it is in motion.

Gravity – This allows simulating the effect of gravity on solid objects.

Results & Plots – This allows getting the results and plots for displacement, velocity, force, angles, etc.

Zoom Time Scale – This allows zooming in/out the timeline.

Key Point – This point decides where the motion has to be stopped.

Time line – This shows the moving time frame

MATES :-

Mates are very crucial from analysis point of view as they define what kind of contact is there in between the various parts of the assembly. Mates defines the motion that is going to be taken place between the various parts. There are different types of mates viz. Revolve, helix, coincident, parallel, etc.

These mates defines the type of contact between the parts of assembly.

SOLID BODY CONTACT :-

Solid body contact are used to define the type of contact between two parts of the assembly i.e. if both parts are solid and do not penetrate in each other then this type of contact.

For practical example, watch my video of Oscillations of balls by BSB TECHNOCRATS on Youtube.

Motion Analysis In Solidworks

Motion Analysis In Solidworks

SOLIDWORKS motion analysis uses the assembly mates along with part contacts and a robust physics-based solver to accurately determine the physical movements of an assembly under load. With the assembly motion and forces calculated, a structural analysis of the components can be performed to ensure product performance.

Motion Analysis Overview

There are two types of motion analysis, kinematic and dynamic:

• Kinematic analysis studies how your design moves due to forces and motions drivers applied to the assembly. The key results of interest are the assembly range of motion and determining part displacements, velocities, and accelerations.
• Dynamic motion analysis evaluates the forces generated by movement, as well as the movement itself.

Motion analysis can be solved using two different solution paradigms, time based motion and event based motion:

TIME- BASED ANALYSIS:-

• In a time-based analysis, external actions occur at a pre-set time irrespective of the assembly motion.
• Easily evaluate how your product will perform and move throughout its operational cycle with motion analysis using SOLIDWORKS Simulation. Visualize your product moving as it would in the real world and measure the forces and loads on your design. Plus, use the data to correctly size motors and create the ‘correct’ mechanism to ensure performance, product quality, and safety.
  Tightly integrated with SOLIDWORKS CAD, motion analysis using SOLIDWORKS Simulation can be a regular part of your design process—reducing the need for costly prototypes, eliminating rework or delays, and saving time and development costs.

Time- Based Motion Analysis Overview

• Motion analysis is solved using a time-based approach for rigid body kinematic and dynamic problems. SOLIDWORKS Motion takes the designer beyond the free drag movement available in a CAD environment and into a true physical calculation of the forces and motions of an assembly as it would move under environmental loads (external forces) and/or internal loads (motors, springs, and dampers).
  SOLIDWORKS Motion simulation can calculate the effect of:
  • Forces
  • Springs
  • Dampers
  • Gravity
  • Contact between components
  • Bushings
  Once the assembly motion has been calculated, a structural analysis of the components under the motion-induced loads (accelerations and joint forces) can easily be carried out, either within the motion study or exported to a structural analysis study.

EVENT BASED ANALYSIS:-

• In an event based motion analysis, the motion of the assembly triggers the external action.
• asily simulate complex machine operations using event-based motion analysis with SOLIDWORKS Simulation and validate the sequencing of the design to ensure correct operation, product quality, and safety. See how your product would move in the real world and measure the forces and loads while you design, helping you correctly size the motors and the structure and confirm the timing.
  Tightly integrated with SOLIDWORKS CAD, event-based motion analysis using SOLIDWORKS Simulation can be a regular part of your design process—reducing the need for costly prototypes, eliminating rework or delays, and saving time and development costs.

Event-Based Motion Analysis Overview

• In many cases, machine operation is based on triggers and sensors that activate machine action, such as a parcel being automatically sorted. Event-based motion is a complementary approach to solving kinematic and dynamic rigid body problems using SOLIDWORKS Motion, and has been developed to meet the needs of today’s more complex machine designs.
  Event-based motion analysis is a solution method for rigid body motion where external actions (forces motion drivers) are triggered by the movement or the state of the assembly, rather than the time of the analysis. This approach has great advantages in the early stages of a design when product timings are not yet finalized.
  Event-based motion can solve either kinematic or dynamic rigid body motion problems, and can simulate the effect of:
  • Forces
  • Springs
  • Dampers
  • Gravity
  • Contact between components
  • Bushings
  Once the assembly motion has been calculated, a structural analysis of the components under the motion induced loads (accelerations and joint forces) can easily be carried out, either within the motion study or exported to a structural analysis study.

Event Based Motion Simulation

Hello friends,



Today we are going to discuss about Event based Motion simulation.



Event based motion simulation is a type of motion simulation in solidworks in which we study a motion which is not continuous i.e. motion takes place for a certain period of time in a cycle and for the rest of period of time, that part is stationary.



For example, consider an automobile engine. In Engine, there are various parts moving like piston, crank, connecting rod, cam & rocker assembly. Some of the parts are moving continuously like piston, crank and some parts move for a certain period of time like inlet and outlet valves, rocker arm. This type of motion is called event-based motion study and this can be done on the solid works under Event-based simulation.



For more clarity on this topic, see this video



https://youtu.be/yMZrf9xk7hs