The Cross-section Solver provides comprehensive analysis of structural cross-sections, calculating geometric properties, elastic properties, plastic properties, and warping characteristics using the sectionproperties library.

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Input Parameters

Most parameters are optional, but enough information must be provided to create a stable structure with:
  • Both stiffnesses (EA and EI)
  • Length specification
  • At least 1-2 supports
  • At least one strength load case/combination
  • At least one serviceability load combination

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Core Configuration

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sectionsData
array
required
Array of section dictionaries following sectionproperties Documentation format with additional ClearCalcs-specific entries.Note: You may see std_* parameters in past examples. These don’t do anything currently and are simply passed through. They were intended for cross-section design linking.
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sectionsData[n]['type']
string
required
String describing the section type. Full names from sectionproperties documentation are available, plus abbreviated names.
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sectionsData[n]['mirror']
string
Mirror the section about an axis. Options: "x", "y", or "null"
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sectionsData[n]['rot']
number
Rotate section counterclockwise by specified degrees. Use null for no rotation.
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materialsData
object
Dictionary of material names and their properties.Default: {"default": {"E": 1, "nu": 0, "fy": 1, "color": "#000", "lineWeight": 3}}Properties include:
  • E: Elastic modulus
  • nu: Poisson’s ratio
  • fy: Yield strength
  • color: Line color
  • lineWeight: Line weight for display

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Analysis Configuration

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analysisType
string
default:"none"
Type of analysis to perform:
  • "none": No analysis (geometry only)
  • "elastic": Elastic analysis only
  • "warping": Elastic + warping analysis
  • "plastic": Elastic + plastic analysis
  • "frame": Optimized analysis for frame properties
  • "full": Complete analysis (elastic + warping + plastic)
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checkGeom
string
default:"none"
Geometry validity checking:
  • "check": Issue error messages for problems
  • "clean": Try to fix geometry issues automatically
  • "none": No geometry checking

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Mesh and Output Configuration

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defaultMeshFactor
number
default:"100"
Maximum mesh size = gross area / this factor
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meshColor
string
default:"#AAA"
Color for mesh lines in output
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meshWeight
integer
default:"1"
Line weight for mesh lines
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zeroTol
float
default:"1e-16"
Tolerance below which results are rounded to zero. Engineering applications typically use 1e-6.
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lenUnit
string
required
Unit for length outputs. Must be valid mathjs unit (e.g., ‘m’ for SI, ‘ft’ for US)
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forceUnit
string
required
Unit for force outputs. Must be valid mathjs unit (e.g., ‘N’ for SI, ‘kip’ for US)

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Output Properties

All outputs are accessible via solverRefId.propertyName where solverRefId is your solver’s reference ID.

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Always Available (All Analysis Types)

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lines
array
All lines making up the cross-section (excluding mesh)
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dimensions
array
Default dimensions for cross-section diagrams. Includes all input dimensions.
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domain
array
2×2 array of outer domain extents: [[xmin, ymin], [xmax, ymax]]
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points
array
n×2 array of all points/nodes: [[x1, y1], [x2, y2], ...]
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facets
array
n×2 array of all elements: [[node0, node1], ...]
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holes
array
Points located within empty regions
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control_points
array
Points located within filled regions
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shift
array
Amount by which each geometry was shifted

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Elastic Results

Available for elastic, warping, plastic, and full analysis types:

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Basic Properties

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A
number
Gross area
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cx, cy
number
Centroid location (X, Y coordinates)
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rx, ry
number
Radius of gyration about centroidal axes
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r11, r22
number
Radius of gyration about principal axes
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phi
number
Angle of major principal axis

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Stiffness Properties

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EA
number
Axial stiffness
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EQx, EQy
number
First moment of area about global axes
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EIxx, EIyy, EIxy
number
Second moment of area about centroidal axes
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EI11, EI22, EI12
number
Second moment of area about principal axes
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EIxxg, EIyyg, EIxyg
number
Second moment of area about global axes

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Section Moduli

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EZxxp, EZxxm
number
Elastic section modulus for positive/negative bending about centroidal X-axis
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EZyyp, EZyym
number
Elastic section modulus for positive/negative bending about centroidal Y-axis
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EZxx, EZyy
number
Minimum elastic section modulus (min of positive/negative)
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EZ11p, EZ11m, EZ22p, EZ22m
number
Elastic section modulus about principal axes
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EZ11, EZ22
number
Minimum elastic section modulus about principal axes

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Same Stiffness Outputs

When all sections have identical stiffness, additional properties without ‘E’ prefix are available: Qx, Qy, Ixx, Iyy, Ixy, I11, I22, I12, Ixxg, Iyyg, Ixyg, Zxxp, Zxxm, Zyyp, Zyym, Zxx, Zyy, Z11p, Z11m, Z22p, Z22m, Z11, Z22

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Plastic Properties

Available for plastic and full analysis types:
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cxp, cyp
number
Plastic centroid location
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c11p, c22p
number
Plastic centroid location on principal axes
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fySxx, fySyy
number
Plastic section modulus about centroidal axes
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fyS11, fyS22
number
Plastic section modulus about principal axes

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Same Yield Stress Outputs

When all sections have identical yield stress: Sxx, Syy, S11, S22

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Warping Properties

Available for warping and full analysis types:

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Shear Centers

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x0, y0
number
Shear center location
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x011, y022
number
Shear center on principal axes
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x0t, y0t
number
Taffetz shear center location

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Monosymmetry Constants

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betaxp, betaxm, betayp, betaym
number
Monosymmetry constants for positive/negative bending about centroidal axes
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beta11p, beta11m, beta22p, beta22m
number
Monosymmetry constants about principal axes

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Advanced Properties

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EJ
number
St Venant’s torsion constant
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EIw
number
Warping constant
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EAsx, EAsy
number
Shear area about centroidal axes
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EAs11, EAs22
number
Shear area about principal axes

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Same Stiffness Outputs

When all sections have identical stiffness: J, Iw, Asx, Asy, As11, As22

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Frame Properties

For analysisType: "frame" - optimized subset for frame analysis:
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A
number
Gross area
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phi
number
Angle of major principal axis
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EA
number
Axial stiffness
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EJ
number
St Venant torsion constant
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EQx, EQy
number
First moment of area about global axes
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EIxx, EIyy, EIxy
number
Second moment of area about centroidal axes

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Example Usage

{
  "type": "remote",
  "referenceId": "section_analysis",
  "solver": "crossSection",
  "inputs": {
    "sectionsData": [
      {
        "type": "rectangular",
        "b": 200,
        "h": 300,
        "material": "steel"
      }
    ],
    "materialsData": {
      "steel": {
        "E": 200000,
        "nu": 0.3,
        "fy": 250,
        "color": "#1f77b4",
        "lineWeight": 2
      }
    },
    "analysisType": "full",
    "lenUnit": "mm",
    "forceUnit": "N"
  }
}

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Best Practices

  1. Analysis Type Selection: Choose the minimum analysis type needed for your calculations to optimize performance
  2. Unit Consistency: Ensure lenUnit and forceUnit match your template’s unit system
  3. Geometry Validation: Use checkGeom: "clean" for robust geometry handling
  4. Material Properties: Define realistic material properties for accurate results
  5. Mesh Control: Adjust defaultMeshFactor based on section complexity and required accuracy

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Performance Considerations

  • "frame" analysis type is fastest and most reliable for basic frame properties
  • "full" analysis provides complete results but takes longer
  • Complex geometries may require geometry cleaning (checkGeom: "clean")
  • Large defaultMeshFactor values create finer meshes but slower analysis
When using complex geometries, test with checkGeom: "check" first to identify potential issues before using "clean" mode.