Karamba3D v3
  • Welcome to Karamba3D
  • New in Karamba3D 3.1
  • See Scripting Guide
  • See Manual 2.2.0
  • 1 Introduction
    • 1.1 Installation
    • 1.2 Licenses
      • 1.2.1 Cloud Licenses
      • 1.2.2 Network Licenses
      • 1.2.3 Temporary Licenses
      • 1.2.4 Standalone Licenses
  • 2 Getting Started
    • 2 Getting Started
      • 2.1 Karamba3D Entities
      • 2.2 Setting up a Structural Analysis
        • 2.2.1 Define the Model Elements
        • 2.2.2 View the Model
        • 2.2.3 Add Supports
        • 2.2.4 Define Loads
        • 2.2.5 Choose an Algorithm
        • 2.2.6 Provide Cross Sections
        • 2.2.7 Specify Materials
        • 2.2.8 Retrieve Results
      • 2.3 The Karamba3D Menu
      • 2.4 User Settings
      • 2.5 Physical Units
      • 2.6 Asynchronous Execution of Karamba3D Components
      • 2.7 Quick Component Reference
  • 3 In Depth Component Reference
    • 3.0 Settings
      • 3.0.1 License
    • 3.1 Model
      • 3.1.1 Assemble Model
      • 3.1.2 Disassemble Model
      • 3.1.3: Modify Model
      • 3.1.4: Connected Parts
      • 3.1.5: Activate Element
      • 3.1.6 Create Linear Element
        • 3.1.6.1 Line to Beam
        • 3.1.6.2 Line to Truss
        • 3.1.6.3 Connectivity to Beam
        • 3.1.6.4: Index to Beam
      • 3.1.7 Create Surface Element
        • 3.1.7.1: Mesh to Shell
        • 3.1.7.2: Mesh to Membrane
      • 3.1.8: Modify Element
      • 3.1.9: Point-Mass
      • 3.1.10: Disassemble Element
      • 3.1.11: Make Element-Set
      • 3.1.12: Orientate Element
      • 3.1.13: Dispatch Elements
      • 3.1.14: Select Elements
      • 3.1.15: Support
    • 3.2: Load
      • 3.2.1: General Loads
      • 3.2.2: Beam Loads
      • 3.2.3: Disassemble Mesh Load
      • 3.2.4 Load-Case-Combinations
        • 3.2.5.1 Load-Case-Combinator
        • 3.2.5.2 Disassemble Load-Case-Combinaton
        • 3.2.5.3 Load-Case-Combination Settings
    • 3.3: Cross Section
      • 3.3.1: Beam Cross Sections
      • 3.3.2: Shell Cross Sections
      • 3.3.3: Spring Cross Sections
      • 3.3.4: Disassemble Cross Section
      • 3.3.5: Eccentricity on Beam and Cross Section
      • 3.3.6: Modify Cross Section
      • 3.3.7: Cross Section Range Selector
      • 3.3.8: Cross Section Selector
      • 3.3.9: Cross Section Matcher
      • 3.3.10: Generate Cross Section Table
      • 3.3.11: Read Cross Section Table from File
    • 3.4: Joint
      • 3.4.1: Beam-Joints
      • 3.4.2: Beam-Joint Agent
      • 3.4.3: Line-Joint
    • 3.5: Material
      • 3.5.1: Material Properties
      • 3.5.2: Material Selection
      • 3.5.3: Read Material Table from File
      • 3.5.4: Disassemble Material
    • 3.6: Algorithms
      • 3.6.1: Analyze
      • 3.6.2: AnalyzeThII
      • 3.6.3: Analyze Nonlinear WIP
      • 3.6.4: Large Deformation Analysis
      • 3.6.5: Buckling Modes
      • 3.6.6: Eigen Modes
      • 3.6.7: Natural Vibrations
      • 3.6.8: Optimize Cross Section
      • 3.6.9: BESO for Beams
      • 3.6.10: BESO for Shells
      • 3.6.11: Optimize Reinforcement
      • 3.6.12: Tension/Compression Eliminator
    • 3.7 Results
      • 3.7.1 General Results
        • 3.7.1.1 ModelView
        • 3.7.1.2 Result Selector
        • 3.7.1.3 Deformation-Energy
        • 3.7.1.4 Element Query
        • 3.7.1.5 Nodal Displacements
        • 3.7.1.6 Principal Strains Approximation
        • 3.7.1.7 Reaction Forces
        • 3.7.1.8 Utilization of Elements
        • 3.7.1.9 ReactionView
      • 3.7.2 Results on Beams
        • 3.7.2.1 BeamView
        • 3.7.2.2 Beam Displacements
        • 3.7.2.3 Beam Forces
        • 3.7.2.4 Node Forces
      • 3.7.3 Results on Shells
        • 3.7.3.1 ShellView
        • 3.7.3.2 Line Results on Shells
        • 3.7.3.3 Result Vectors on Shells
        • 3.7.3.4 Shell Forces
        • 3.7.3.5 Shell Sections
    • 3.8 Export
      • 3.8.1 Export Model to DStV
      • 3.8.2 Json/Bson Export and Import
      • 3.8.3 Export Model to SAF
      • 3.8.4 Export/Import Model to and from Speckle (WIP)
    • 3.9 Utilities
      • 3.9.1: Mesh Breps
      • 3.9.2: Closest Points
      • 3.9.3: Closest Points Multi-dimensional
      • 3.9.4: Cull Curves
      • 3.9.5: Detect Collisions
      • 3.9.6: Get Cells from Lines
      • 3.9.7: Line-Line Intersection
      • 3.9.8: Principal States Transformation
      • 3.9.9: Remove Duplicate Lines
      • 3.9.10: Remove Duplicate Points
      • 3.9.11: Simplify Model
      • 3.9.12: Element Felting
      • 3.9.13: Mapper
      • 3.9.14: Interpolate Shape
      • 3.9.15: Connecting Beams with Stitches
      • 3.9.16: User Iso-Lines and Stream-Lines
      • 3.9.17: Cross Section Properties
      • 3.9.18 Surface To Truss
    • 3.10 Parametric UI
      • 3.10.1: View-Components
      • 3.10.2: Rendered View
  • Troubleshooting
    • 4.1: Miscellaneous Questions and Problems
      • 4.1.0: FAQ
      • 4.1.1: Installation Issues
      • 4.1.2: Purchases
      • 4.1.3: Licensing
      • 4.1.4: Runtime Errors
      • 4.1.5: Definitions and Components
      • 4.1.6: Default Program Settings
    • 4.2: Support
  • Appendix
    • A.1: Release Notes
      • Work in Progress Versions
      • Older Versions
      • Version 2.2.0
      • Version 2.2.0 WIP
      • Version 1.3.3
      • Version 1.3.2 build 190919
      • Version 1.3.2 build 190731
      • Version 1.3.2 build 190709
      • Version 1.3.2
    • A.2: Background information
      • A.2.1: Basic Properties of Materials
      • A.2.2: Additional Information on Loads
      • A.2.3: Tips for Designing Statically Feasible Structures
      • A.2.4: Performance Optimization in Karamba3D
      • A.2.5: Natural Vibrations, Eigen Modes and Buckling
      • A.2.6: Approach Used for Cross Section Optimization
    • A.3: Workflow Examples
    • A.4: Bibliography
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On this page
  • Concentrated Load
  • Block Load
  • Gap Load
  • Imperfection
  • Polylinear Load
  • Trapezoidal Load
  1. 3 In Depth Component Reference
  2. 3.2: Load

3.2.2: Beam Loads

Previous3.2.1: General LoadsNext3.2.3: Disassemble Mesh Load

Last updated 7 months ago

The group of loads described in this section works on beams and - with some limitations - on truss elements. The latter are considered as shear rigid with hinges at their ends: Beam-loads on trusses transform into transverse forces at their end-points. All beam load-components feature the "BeamID"- and "LCase"-input-plug:

  • "BeamId" determines the element on which to apply the load. A regular expression like '&"id1"|"id2"|...' selects multiple elements.

  • "LCase" specifies the name of the load's load-case.

The parameter "t" serves to specify the load-position along elements: t=0 refers to the starting point, t=1 to the end-point.

Karamba3D offers these types of beam-loads:

Concentrated Load

Use the 'Concentrated'-option to specify forces and moments at arbitrary positions along the element. Vectors 'Force' and 'Moments' let one set the direction and size of the corresponding external loads. Fig 3.2.2.1 shows a cantilever with a span of 3m under a concentrated transverse load of 1kN. The load sits at a distance of 0.75 x 3.00 = 2.25m from the supports and causes a linear bending moment diagram.

The radio buttons in the sub-menu 'Orientation' determine the reference coordinate system of the 'Force'- and 'Moment'-vectors: either local to the element or global.

Block Load

Fig. 3.2.2.2 shows the application of uniformly distributed transverse loads an on a cantilever beam. The span of the cantilever is two meters. The loads act between t0=0.25 and t1=0.75. With the default values t0=0 and t1=1 distributed block-loads cover the whole beam length. The graphical output in fig. 3.2.2.2 shows the support reactions well as the bending-moment-diagram (in orange) for My.

In combination with the radio buttons in sub-menu "Orientation" the vectors at the input-plugs "Force" and "Moment" sets the external loads to be applied - see fig. 3.1.2.8 for the meaning of the different types of orientation.

There are limitations for distributed rotational loads: In case they rotate about the element's local Y- or Z-direction they need to be specified over the whole length. This does not apply to distributed torsional moments when the Orientation is set to 'Local to element'.

The input-plug “LCase” which designates the load case defaults to “0”.

Gap Load

Fig 3.2.2.3 shows a fully fixed beam under a translational gap load of 0.1m in local z-direction. The displaced shape shows, that in order to maximize the shear force Vz at the location of the gap-load one should place transverse external loads either to the left or right side of the gap only.

Imperfection

There exists no such thing as an ideally straight column positioned perfectly vertical. The deviation of a real column from its ideal counterpart is called imperfection. This term comprises geometric and material imperfections.

The “Imperfection” variant of the “Loads” multi-component allows to specify geometric imperfections (see fig. 3.2.2.4). “psi0” takes the vector of the initial inclination of the beam axis about the axes of the local element coordinate system in radians. With “kappa0” one can specify the initial curvature. A positive component of curvature means that the rotation of the middle axis about the corresponding local coordinate axis increases when moving in longitudinal beam direction. Small inclinations and curvatures are assumed.

In fig. 3.2.2.4 one can see displacements and reaction forces of an initially straight beam with a second order theory normal force of NII=10kNN^{II} = 10 kNNII=10kN, an initial inclination of 0.1rad0.1 rad0.1rad about the local y-axis and an initial curvature of 0.1rad/m0.1 rad/m0.1rad/m.

Imperfection loads do not add directly to the beam displacements. They act indirectly and only in the presence of a normal force NIIN^{II}NII. An initial inclination ψ0\psi_0ψ0​ causes transverse loads ψ0⋅NII\psi_0 \cdot N^{II}ψ0​⋅NII at the elements endpoints. An initial curvature κ0\kappa_0κ0​ results in a uniformly distributed line load of magnitude κ0⋅NII\kappa_0 \cdot N^{II}κ0​⋅NII and transverse forces at the elements endpoints that make the overall resultant force zero. For details see e.g. [10].

Polylinear Load

Distributed loads consisting of an arbitrary number of linear segments can be defined via the "Polylinear" option (see fig. 3.2.2.5). The input-plug "Dir" specifies the direction of the load. The vector supplied there gets scaled to unity and has no impact on the load magnitudes. The latter get set by lists of values connected to the "Force" or "Moment" inputs. For each value supplied there needs to be a corresponding location parameter "ts". In case there are more location parameters than force or moment-values the longest list principle applies like in fig. 3.2.2.5.

In case of subsequent identical t-values and different corresponding load-values a step in the distributed load results.

Trapezoidal Load

The 'Trapezoidal'-option makes it more convenient to specify trapezoidal loads as compared to 'Polylinear'. Teh parameter input is simlar to that of block-loads. The four parameters t0, t1, t2 and t3 specify the trapezoids shape.

The input-plug “BeamId” receives the identifier of the beam on which the load shall act. Multiple beams can be specified via a regular expression (e.g. '&"id1"|"id2"...'). See section for how to attach identifiers to beams. By default beams are named after their index in the FE-model. There are three options for the orientation of the load: “local to element”, “global” and “global proj.”. Their meaning corresponds to the options available for mesh-loads (see fig. 3.2.1.8).

With Gap-loads it is possible to prescribe rotation or displacement discuntinuities at arbitrary element-positions. When using unit vectors, the resulting displacement shapes represent influence lines (see e.g. ).

3.1.6
https://en.wikipedia.org/wiki/Influence_line
53KB
PointLoad_OnBeam.gh
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PointLoad_OnTruss.gh
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BlockLoad_Translational_OnBeam.gh
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BlockLoad_Translational_OnTruss.gh
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BlockLoad_Rotational_OnBeam.gh
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Uniformly_Distributed_Line_Load.gh
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Eccentricity_On_Beam_BeamLoads.gh
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GapLoadRotational_OnBeam.gh
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GapLoadTranslational_OnBeam.gh
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GapLoadTranslational_OnTruss.gh
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Imperfection_Spring.gh
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PolyLinearLoad_Translational_OnBeam.gh
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TrapezoidLoad_Translational_OnBeam.gh
Fig 3.2.2.1: Cantilever beam with concentrated transverse load: support reactions and My-diagram
Fig. 3.2.2.2: Cantilever beam with constant transverse load: support reactions and My-diagram
Fig. 3.2.2.3: Fully fixed beam with gap-load wz=0.1[m]
Fig. 3.2.2.4: Imperfection Load
Fig. 3.2.2.5: Cantilever beam under poly-linear transverse distributed load
Fig. 3.2.2.6: Cantilever beam under trapezoidal transverse distributed load