Wind Load

Wind load is the force exerted by wind on a structure.

It's a type of pressure that varies with wind speed, height, and the shape of the object. SimSolid can apply wind loads based on user-defined parameters, such as wind speed and direction, to simulate the effects of wind on buildings, signs, or other structures.

Theory of Wind Loads

In structural analysis, wind load denotes the force imposed by wind on a structure.

Wind load is influenced by factors like height above the ground and velocity. These forces can profoundly impact the stability and structural integrity of structures and buildings. SimSolid plays a crucial role in modeling wind loads on structures by considering key factors such as wind speed, air density, directionality, frictional drag, and shape factor. By incorporating these parameters, SimSolid facilitates the evaluation of pressure exerted on surfaces exposed to the wind, contributing to accurate calculations of structural deflection.

A pivotal influence on wind load considerations is the wind profile. SimSolid supports two distinct profiles: Uniform and Logarithmic. These profiles serve as mathematical models, elucidating the uniform distribution or logarithmic progression of wind speed concerning the height above the ground (H) within the atmospheric boundary layer.

Figure 1.


In the Logarithmic wind profile, the interpolation points along the logarithmic curve between the height above the ground (H) and wind speed (V) are calculated by the following equation.
V ( z ) = u κ ln ( H + 1 ) MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOvaiaacI cacaWG6bGaaiykaiabg2da9maalaaabaGaamyDaaqaaGGaaiab=P7a RbaaciGGSbGaaiOBaiaacIcacaWGibGaey4kaSIaaGymaiaacMcaaa a@4294@
Where,
u
Shear velocity (Default = ~0.5)
κ MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaaccaGae8NUdS gaaa@37AA@
Von Karman constant (Default = ~0.41)
H
Height above ground where velocity was measured
The wind pressure for surfaces that are normal to the wind direction is calculated by the following equation.
P w i n d = 1 2 ρ a i r V 2 C MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiuamaaBa aaleaacaWG3bGaamyAaiaad6gacaWGKbaabeaakiabg2da9maalaaa baGaaGymaaqaaiaaikdaaaGaeqyWdi3aaSbaaSqaaiaadggacaWGPb GaamOCaaqabaGccaWGwbWaaWbaaSqabeaacaaIYaaaaOGaam4qaaaa @44A8@
Where,
P w i n d MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiuamaaBa aaleaacaWG3bGaamyAaiaad6gacaWGKbaabeaaaaa@3ABA@
Wind pressure
ρ a i r MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqyWdi3aaS baaSqaaiaadggacaWGPbGaamOCaaqabaaaaa@3AAA@
Air density
V
Speed of the wind
C
Shape factor

For the surfaces which are parallel to the wind direction includes frictional drag ( C f MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4qamaaBa aaleaacaWGMbaabeaaaaa@37D2@ ) is calculated by, the following equation.

P w i n d = 1 2 ρ a i r C f V 2 C MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiuamaaBa aaleaacaWG3bGaamyAaiaad6gacaWGKbaabeaakiabg2da9maalaaa baGaaGymaaqaaiaaikdaaaGaeqyWdi3aaSbaaSqaaiaadggacaWGPb GaamOCaaqabaGccaWGdbWaaSbaaSqaaiaadAgaaeqaaOGaamOvamaa CaaaleqabaGaaGOmaaaakiaadoeaaaa@4691@
The default value of friction drag coefficient is set to 0.01.

Tip: The Enable Shielding checkbox provides capability to protect components from wind load that are obstructed by other parts. When unchecked, wind load is exerted on all components, regardless of whether the surfaces facing the wind source are obstructed by other parts within the assembly.

Create Wind Profile

Define the wind profile using one of the following methods

Wind profile is one of the essential inputs when applying wind load to the structure. There are multiple methods for creating wind profile in SimSolid.
  1. In the Project Tree, click the structural analysis in which the wind load BC will be applied.
  2. On the Analysis Workbench, click (Wind load).
  3. Click Create profile and create a wind profile in one of the following ways.
    ToDo this
    Import from external CSV
    1. In the dialog, click Import CSV.
    2. Browse to the desired file and click Open.
    Note: The file contents must have a header row followed by two or more rows of data. Each row has two to three values. Values must be separated with commas. The first is speed and the second is height above ground.
    Speed
    Height above ground
    0
    0
    10
    4
    38
    9
    47
    13
    61
    18
    Create from standard template function
    1. In the dialog, click Standard.
    2. In the Function type drop-down, select the desired template.
    3. For Uniform, specify Speed (V) and Height above ground (H).
    4. For Logarithmic, define Shear velocity (u), von-Karman constant (k) and Height above ground (H).
    5. Click OK.
    Create manually
    1. In the dialog, click Add row. A new row will appear in the dialog's table.
    2. Click in the row under Point #, Speed, or Height above ground to activate a text box.
    3. Enter desired values.
  4. Click OK.

Create Wind Load

Apply wind load based on wind profile for structural analysis

  1. In the Project Tree, click on a structural analysis to open the Analysis Workbench, then select Structural linear or Structural non-linear.
  2. On the Analysis Workbench, click Pressure > Wind load.
    The Wind Load dialog opens.
  3. Click Create profile and create a wind profile in one of the following ways.
    ToDo this
    Import from external CSV
    1. In the dialog, click Import CSV.
    2. Browse to the desired file and click Open.
    Note: The file contents must have a header row followed by two or more rows of data. Each row has two to three values. Values must be separated with commas. The first is speed and the second is height above ground.
    Speed
    Height above ground
    0
    0
    10
    4
    38
    9
    47
    13
    61
    18
    Create from standard template function
    1. In the dialog, click Standard.
    2. In the Function type drop-down, select the desired template.
    3. For Uniform, specify Speed (V) and Height above ground (H).
    4. For Logarithmic, define Shear velocity (u), von-Karman constant (k) and Height above ground (H).
    5. Click OK.
    Create manually
    1. In the dialog, click Add row. A new row will appear in the dialog's table.
    2. Click in the row under Point #, Speed, or Height above ground to activate a text box.
    3. Enter desired values.
  4. Click OK.
  5. Click the Ground tab to place the origin of the wind load. Coordinates can be either manually entered or it can be placed by dragging the origin point from the modeling window.
  6. Optional: Define Wind direction and Height axis in their respective tabs.
  7. Optional: Enter values for Air density, Friction coefficient, and Shape factor.
    By default, they are set to 1.2 kg/m3, 0.01, and 1 respectively.
  8. Optional: To protect parts from the wind load that are obstructed by other parts, select the Enable shielding checkbox.
    Note: Without Enable Shielding, wind load is exerted on all components, regardless of whether their surfaces facing the wind source are obstructed by other parts within the assembly.
  9. Click OK.