---
type: concept
title: "Midas Civil Element Library and Section Stiffness"
created: 2026-06-02
updated: 2026-06-02
address: c-000160
aliases:
  - MIDAS Civil element library
  - midas Civil section stiffness
tags:
  - concept
  - finite-element-method
  - midas-civil
  - elements
status: current
related:
  - "[[Midas-Civil-Analysis-Reference|Midas Civil Analysis Reference]]"
  - "[[midas Civil]]"
  - "[[Beam and Frame Finite Elements]]"
  - "[[Plane Stress and Plane Strain Elements]]"
  - "[[Isoparametric Linear Solid Elements]]"
  - "[[Midas FEA Element Library]]"
sources:
  - "[[Midas-Civil-Analysis-Reference|Midas Civil Analysis Reference]]"
source_refs:
  - source: "[[Midas-Civil-Analysis-Reference|Midas Civil Analysis Reference]]"
    raw_path: ".raw/MidasCivilAnalysisReference/"
    raw_files:
      - "MidasCivilAnalysisReference_014.md"
      - "MidasCivilAnalysisReference_020.md"
      - "MidasCivilAnalysisReference_011.md"
      - "MidasCivilAnalysisReference_012.md"
    md_indices:
      - 14
      - 20
      - 11
      - 12
    match: "heuristic-heading-keyword"
    confidence: low
---

# Midas Civil Element Library and Section Stiffness

## Definition

Midas Civil element library and section stiffness is the product layer that maps structural members and continua to finite element types and their required stiffness data.

## How It Works

The analysis reference lists truss, tension-only hook, cable, compression-only gap, beam, tapered beam, plane stress, plane strain, axisymmetric, plate, and solid elements. Element input combines type, material, stiffness data, location, shape, size, and connection node numbers.

Section and stiffness requirements depend on element family. Truss, tension-only, and compression-only elements need cross-sectional area. Beam elements need section properties. Plane stress and plate elements need thickness. Plane strain, axisymmetric, and solid elements use material and geometry without a separate section input. SRC beams and composite sections require equivalent stiffness handling.

## Solver Development Notes

- Element type should determine DOF set, interpolation, local axes, required property schema, and result recovery.
- Effective shear area must be explicit because omitting it changes shear-deformation stiffness.
- Torsional stiffness should not be blindly equated with polar moment except for appropriate circular or tube sections.
- Composite and construction sections require time- or stage-dependent effective properties.

## Connections

- [[Beam and Frame Finite Elements]] covers member stiffness ideas.
- [[Plane Stress and Plane Strain Elements]] and [[Isoparametric Linear Solid Elements]] cover continuum families.
- [[Midas FEA Element Library]] is the detail-FE sibling reference.
- [[Abaqus Element Library]] is the broad production-library comparison point.