Elastic shaft
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| C | |
| in the palette | on the schematic |
The block is designed to simulate an elastic shaft. The shaft is divided into a predetermined number of elements that simulate the rotary motion of the shaft part under the action of internal viscoelastic torques caused by the deformation of the shaft. The deformation of the shaft is defined as the difference between the turn angles and the angular speeds of the partition elements.
The shaft moment of inertia, the stiffness factor and the damping factor can be defined manually or calculated based on the geometric dimensions of the round shaft and the material properties. In this case, the mechanical characteristics are calculated by the formulas:
where:
- JP – polar moment of inertia for the shaft cross-section, m4
- DO and DI – outer and inner diameters of the hollow shaft, m
- J – moment of inertia of the shaft, kg·m2
- ρ – material density, kg/m3
- L – shaft length, m
- K – elasticity coefficient of the shaft, Nm/rad
- E – material elastic modulus, Pa
- D – damping factor of the shaft, Nm·s/rad
- C – viscosity damping factor of the shaft
The block allows you to change the direction of the "C" and "R" ports for easy connection to other blocks of the model:
- If the ports are input, then the block is represented as N inertia moments and N+1 viscoelastic elements connecting the partition elements and blocks connected to the ports of this block
- If the ports are output, the block is represented as N inertia moments and N-1 viscoelastic elements connecting the partition elements. Blocks connected to the ports of this block will connect directly to the first and to the Nth parts. Initial positions and speeds at ports "C" and "R" are determined by the first and N elements of the arrays of initial angular positions and speeds
Ports
| Name | Description | Connection line type |
|---|---|---|
| C | Port for connecting conditionally fixed (case) blocks of the model. The port can be input or output, depending on the selected value in the "Port type" property | Rotary mechanics |
| R | Port for connecting conditionally movable (rotor) blocks of the model. The port can be input or output, depending on the selected value in the "Port types" property | Rotary mechanics |
Properties
| Name | Parameter | Description | By default | Data type |
|---|---|---|---|---|
| Port types | mod_type | Allows you to set the type of ports. The image of the block changes depending on the selected value. The possible values are: "Input", "Output" | Input | Перечисление |
| Number of partition elements | N | Number of partition elements | 5 | Целое |
| Mechanical characteristics | A group of properties that define the mechanical characteristics of the shaft | |||
| How to set the mechanical characteristics | ChType | Allows you to define the method of setting the mechanical characteristics. The possible values are: “Manual", "Material properties" | Manual | Перечисление |
| Shaft length, m | L | Shaft length. The property is available when selecting the mechnical characteristics defining method as "Material properties" | 1 | Вещественное |
| Outer shaft diameter, m | Do | Outer shaft diameter. The property is available when selecting the mechnical characteristics defining method as "Material properties" | 0.01 | Вещественное |
| Inner shaft diameter, m | Di | Inner shaft diameter. The property is available when selecting the mechnical characteristics defining method as "Material properties" | 0 | Вещественное |
| Material density, kg/m3 | Rho | Material density The property is available when selecting the mechnical characteristics defining method as "Material properties" | 7800 | Вещественное |
| Material elastic modulus, Pa | E | Material elastic modulus. The property is available when selecting the mechnical characteristics defining method as "Material properties" | 7.93E10 | Вещественное |
| Viscosity damping factor | C | Viscosity damping factor. The property is available when selecting the mechnical characteristics defining method as "Material properties" | 0.01 | Вещественное |
| Stiffness factor, N·m/rad | K | Stiffness factor. The property is available when selecting the method of defining the mechanical characteristics "Material properties" and is displayed in the "Read-only" mode, is for reference only | 100 | Вещественное |
| Damping factor, N·s/rad. | D | Damping factor. The property is available when selecting the method of defining the mechanical characteristics "Material properties" and is displayed in the "Read-only" mode, is for reference only | 1 | Вещественное |
| Moment of inertia, kg·m2 | J | Moment of inertia. The property is available when selecting the method of defining the mechanical characteristics "Material properties" and is displayed in the "Read-only" mode, is for reference only | 1 | Вещественное |
| Initial conditions | A group of properties that define the initial conditions | |||
| Array of initial angular positions of partition elements, rad | Fi0 | Array of initial angular positions of partition elements. The number of array elements must be equal to "Number of partition elements" | [0 , 0 , 0 , 0 , 0] | Массив |
| Array of initial speeds of partition elements, rad/s | W0 | Array of initial speeds of partition elements. The number of array elements must be equal to "Number of partition elements" | [0 , 0 , 0 , 0 , 0] | Массив |
Parameters
| Name | Parameter | Description | Data type |
|---|---|---|---|
| Power imbalance (Qc-Qr), W | Q | Power taken by the shaft for internal deformations | Вещественное |
| Port C | A group of parameters displaying the parameters of rotary motion at the port "C" | ||
| Turn angle, rad | Fic | Turn angle value at the port "C" | Вещественное |
| Angular speed, rad/s | Wc | Angular speed value at the port "C" | Вещественное |
| Angular acceleration, rad/s2 | Epsc | Angular acceleration value at the port "C" | Вещественное |
| Torque, Nm | Tc | Torque with which the connected blocks act on port "C" | Вещественное |
| Port R | A group of parameters displaying the parameters of rotary motion at the port "R" | ||
| Turn angle, rad | Fir | Value of the turn angle at the port "R" | Вещественное |
| Angular speed, rad/s | Wr | Value of the angular speed at the port "R" | Вещественное |
| Angular acceleration, rad/s2 | Epsr | Value of the angular acceleration at the port "R" | Вещественное |
| Torque, Nm | Tr | Torque with which the connected blocks act on port "R" | Вещественное |
Examples
Examples of block application: