Karamba3D v1.3.3
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English 英文
  • Welcome to Karamba3D
  • 1: Introduction
    • 1.1: Installation
    • 1.2: Licenses
      • 1.2.1: Cloud Licenses
      • 1.2.2: Network Licenses
        • 1.2.2.1: Network license (archived)
      • 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: Physical Units
      • 2.4: Quick Component Reference
  • 3: In Depth Component Reference
    • 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: Line to Beam
      • 3.1.7: Connectivity to Beam
      • 3.1.8: Index to Beam
      • 3.1.9: Mesh to Shell
      • 3.1.10: Modify Element
      • 3.1.11: Point-Mass
      • 3.1.12: Disassemble Element
      • 3.1.13: Make Beam-Set 🔷
      • 3.1.14: Orientate Element
      • 3.1.15: Select Element
      • 3.1.16: Support
    • 3.2: Load
      • 3.2.1: Loads
      • 3.2.2: Disassemble Mesh Load
      • 3.2.3: Prescribed displacements
    • 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: Beam-Joint Agent 🔷
      • 3.3.6: Beam-Joints 🔷
      • 3.3.7: Eccentricity on Beam and Cross Section 🔷
      • 3.3.8: Modify Cross Section 🔷
      • 3.3.9: Cross Section Range Selector
      • 3.3.10: Cross Section Selector
      • 3.3.11: Cross Section Matcher
      • 3.3.12: Generate Cross Section Table
      • 3.3.13: Read Cross Section Table from File
    • 3.4: Material
      • 3.4.1: Material Properties
      • 3.4.2: Material Selection
      • 3.4.3: Read Material Table from File
      • 3.4.4: Disassemble Material 🔷
    • 3.5: Algorithms
      • 3.5.1: Analyze
      • 3.5.2: AnalyzeThII 🔷
      • 3.5.3: Analyze Nonlinear WIP
      • 3.5.4: Large Deformation Analysis
      • 3.5.5: Buckling Modes 🔷
      • 3.5.6: Eigen Modes
      • 3.5.7: Natural Vibrations
      • 3.5.8: Optimize Cross Section 🔷
      • 3.5.9: BESO for Beams
      • 3.5.10: BESO for Shells
      • 3.5.11: Optimize Reinforcement 🔷
      • 3.5.12: Tension/Compression Eliminator 🔷
    • 3.6: Results
      • 3.6.1: ModelView
      • 3.6.2: Deformation-Energy
      • 3.6.3: Nodal Displacements
      • 3.6.4: Principal Strains Approximation
      • 3.6.5: Reaction Forces 🔷
      • 3.6.6: Utilization of Elements 🔷
      • 3.6.7: BeamView
      • 3.6.8: Beam Displacements 🔷
      • 3.6.9: Beam Forces
      • 3.6.10: Resultant Section Forces
      • 3.6.11: ShellView
      • 3.6.12: Line Results on Shells
      • 3.6.13: Result Vectors on Shells
      • 3.6.14: Shell Forces
    • 3.7: Export 🔷
      • 3.7.1: Export Model to DStV 🔷
    • 3.8 Utilities
      • 3.8.1: Mesh Breps
      • 3.8.2: Closest Points
      • 3.8.3: Closest Points Multi-dimensional
      • 3.8.4: Cull Curves
      • 3.8.5: Detect Collisions
      • 3.8.6: Get Cells from Lines
      • 3.8.7: Line-Line Intersection
      • 3.8.8: Principal States Transformation 🔷
      • 3.8.9: Remove Duplicate Lines
      • 3.8.10: Remove Duplicate Points
      • 3.8.11: Simplify Model
      • 3.8.12: Element Felting 🔷
      • 3.8.13: Mapper 🔷
      • 3.8.14: Interpolate Shape 🔷
      • 3.8.15: Connecting Beams with Stitches 🔷
      • 3.8.16: User Iso-Lines and Stream-Lines
  • Troubleshooting
    • 4.1: Miscellaneous Questions and Problems
      • 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
      • 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: Hints on Reducing Computation Time
      • A.2.5: Natural Vibrations, Eigen Modes and Buckling
      • A.2.6: Approach Used for Cross Section Optimization
    • A.3: Bibliography
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On this page
  • Material Stiffness
  • Table A.2.1.1: Young's Modulus of materials (E-values) for some popular building materials
  • Specific Weight
  • Theoretical Background of Stiffness, Stress and Strain

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  1. Appendix
  2. A.2: Background information

A.2.1: Basic Properties of Materials

PreviousA.2: Background informationNextA.2.2: Additional Information on Loads

Last updated 4 years ago

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Material Stiffness

The stiffness i.e. resistance of a material against deformation is characterized by its Young’s Modulus or modulus of elasticity “E”. The higher its value the stiffer the material.

Table A.2.1.1: Young's Modulus of materials (E-values) for some popular building materials

Type of material

steel

21000

aluminum

7000

reinforced concrete

3000

glass fiber

7000

wood (spruce)

1000

For composite materials – like in the case of rods made from glass fiber and epoxy – it is necessary to defer a mean value for “E” using material tests. Karamba3D expects the input for “E” to be in kilo Newton per square centimeter (kN/cm2kN/cm^2kN/cm2).

If one stretches a piece of material it not only gets longer but also thinner: it contracts laterally. In case of steel for example lateral strain amounts to 30% of the longitudinal strain. In case of beams with a large ratio of cross section height to span this effect influences the displacement response.

In common beam structures however this effect is of minor importance. The shear modulus “G” describes material behavior in this respect.

Specific Weight

The value of “gamma” is expected to be in kilo Newton per cubic meter (kN/cm3kN/cm^3kN/cm3). This is a force per unit of volume. Due to Earths gravitational acceleration (a=g=9.81kgm/s2a=g=9.81 kg m/s^2a=g=9.81kgm/s2) and according to Newtons law (f=m⋅af=m \cdot af=m⋅a) a mass m of one kilogram acts downwards with a force of f=9.81Nf=9.81Nf=9.81N. For calculating deflections of structures the assumption of f=10Nf=10Nf=10N is accurate enough. If you want a more precise value change the entry “gravity” in the -file. In case of Imperial units the exact value for “gravity” is automatically set – otherwise the conversion from lbm to lbf does not work properly.

Table A.2.1.1 gives specific weights of a number of typical building materials. The weight of materials only takes effect if gravity is added to a load case (see section ).

Theoretical Background of Stiffness, Stress and Strain

Strain is the quotient between the increase of length of a piece of material when loaded and its initial length. Usually one uses the Greek letter εεε for strains. Stress is force per unit of area. From the stress in a beam cross-section one can calculate the normal force that it withstands by adding up (integrating) the product of area and stress in each point of the cross-section. Stress is normally symbolized by the Greek letter σσσ . Linear elastic materials show a linear dependence between stress and strain. The relation is called Hooke’s Law and looks like this:

σ=E⋅εσ = E \cdot εσ=E⋅ε

Hooke’s law expresses the fact that the more you deform something the more force you have to apply.

E[kN/cm2]E [kN/cm^2]E[kN/cm2]
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3.2.1