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
  • 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
  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 7 months ago

Material Stiffness

The stiffness of a material, or its resistance to deformation, is characterized by its Young’s Modulus (modulus of elasticity "E"). The higher the value of "E," 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, such as glass fiber rods reinforced with epoxy, the mean value of "E" must be determined through material testing. Karamba3D expects the input for "E" to be in kilonewtons per square centimeter (kN/cm²).

When a material is stretched, it not only elongates but also contracts laterally. For instance, in steel, the lateral strain is typically 30% of the longitudinal strain. This effect influences displacement responses in beams with large height-to-span ratios, although it is generally of minor importance in standard beam structures. The shear modulus (G) describes material behavior in this context..

Specific Weight

The specific weight, represented by γ (gamma), should be provided in kilonewtons per cubic meter (kN/m³), indicating force per unit volume. Due to Earth’s gravitational acceleration (g ≈ 9.81 m/s²), according to Newton's Law (F = ma), a mass of 1 kg exerts a downward force of approximately 9.81 N. For calculating deflections of structures the assumption of f=10Nf=10Nf=10N is accurate enough. If greater precision is required, the gravity constant can be adjusted in the "karamba.ini" file. For Imperial units, the exact value for gravity is automatically set to ensure correct conversion from lbm to lbf.

Table A.2.1.1 lists specific weights for various common building materials. Material weight only affects calculations when gravity is included in a load case (refer to section 3.2.1).

Theoretical Background of Stiffness, Stress and Strain

Strain (denoted by ε) is the ratio of the elongation of a material under load to its original length. Stress (denoted by σ) is the force per unit area. In a beam cross-section, normal forces can be calculated by integrating the product of area and stress across the cross-section.

For linear elastic materials, the relationship between stress and strain is linear, governed by Hooke’s Law, which states that the force required to deform a material increases proportionally with the amount of deformation:

This law expresses the principle that greater deformation requires greater applied force.

σ=E⋅εσ = E \cdot εσ=E⋅ε

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