MITC4 Shell Element

This API is a package designed for nonlinear finite element simulations with the MITC4 shell element. The nonlinear analysis is based on the Updated Lagrangian Configuration (co-rotational approach). The package includes the computation of the Stiffness Matrix, the Geometrical (or Initial Stress) Stiffness Matrix, and the Internal Force Vector.

Developed in C++ for Linux and Windows operating systems.

Buckling Analysis with the MITC4 Shell Element

4o

Get to know the MITC4 Shell Element Class

Description of the element's Class; its constructor and Public Methods that can be used.

Mesh Convergence & Aircraft Wing Results

Hemispherical Shell Benchmark: A rigorous convergence test with mesh refinement for testing element's accuracy with warped shell element configurations under large rotations analysis.

Designed to push the limits of element performance under extreme warping, transverse shear, and bending loads.

The MITC4 shell element API achieves fast convergence with mesh refinement.

Explore the gallery for an in-depth analysis of the mesh convergence results and post-processing in our GUI.

Click on the gallery below for the MITC4 Shell API convergence results and post-processing on our GUI for the Hemispherical Shell example.

Aircraft Wing linear elastic simulation with the MITC4 shell API

An application example of the MITC4 Shell API is presented through the linear elastic simulation of an aircraft wing. The wing is fixed at the root (fuselage) and subjected to impulse loading at the landing gear attachment point.

This simulation utilized our free C++ linear elastic template, with pre-processing and post-processing performed using our GUI. The results are showcased in the image gallery below.

Constituents of the API

Stiffness Matrix

Stiffness matrix for the MITC4 shell element. Required for linear and nonlinear analysis.

B-Matrix

Shell element with 4 nodes and full in-plane quadrature rule. User-defined number of integration points along the thickness direction of the shell. Reissner-Mindlin formulation with ANS to alleviate transverse shear locking. Ideal for thin shell simulations.

Geometric Stiffness Matrix

Geometric (Initial Stresses) Stiffness matrix for the MITC4 shell element. It is required for nonlinear analysis with implicit time integration scheme, buckling analysis, etc.

Internal Force (available soon)

Internal Force vector for the MITC4 shell element. Critical for nonlinear analysis for both explicit and implicit time integration schemes.

Strain Tensor

Strain tensor at all integration points of the element. The strain tensor can be used for different type of constitutive models.

Axes Rotation at the GPs (available soon)

Rotation of local axes at the Gauss Points. Important for nonlinear co-rotational analysis, e.g. rotation of planar plastic anisotropic axes, rotation of composites ply axes at the GPs.

Compile, Install & Use of the API

// STIFFNESS

//

// loop in the elements

for (iel = 0; iel < melems; ++iel) {

.

.

.

// instance of the API: Calls the Constructor for this element

NonlinearShellMITC4 stif(xyz_in,vnor_in,thick_in,xlocal_in,ylocal_in,zetCoord,zetWeigt,stresses,DMatrix_all);

StiffnessTotal = stif.Calculate_StiffnessMITC4();

}

Extract of the free template distributed with the API for the calculation of the stiffness of the element.

NonlinearShellMITC4 is the Class of the API

stif is one Instance of the Class

Calculate_StiffnessMITC4() is a method of the API's Class to calculate the stiffness matrix of the element

The free template provided with the API leverages OpenMP for multi-threading the element loop, significantly accelerating the computation of the total stiffness matrix.

cmake_minimum_required(VERSION 3.22)

project(Linear_Elastic_ShellMITC4)

set(CMAKE_CXX_STANDARD 20)

#

# Include for the header files

set(INCLUDE_DIRS ".../path to the include folder")

include_directories(${INCLUDE_DIRS})

# Specify the name of the library (API)

set(LIBRARY_NAME libNonlinearShellMITC4.so)

set(MYLIB_LIBRARY_DIR ".../path to the library folder")

# Find OpenMP (crucial if multi-threading OpenMP is to be used)

find_package(OpenMP REQUIRED)

# Create the executable

add_executable(${PROJECT_NAME} main.cpp Nodes.cpp Elements.cpp IO_APIs_Shells.cpp

Utils.cpp FaceLoad.cpp)

# Link against the shared library

target_link_directories(${PROJECT_NAME} PUBLIC ${MYLIB_LIBRARY_DIR})

# Link OpenMP to your executable

target_link_libraries(${PROJECT_NAME} PUBLIC armadillo NonlinearShellMITC4 OpenMP::OpenMP_CXX)

CMakeLists.txt file for the linear elastic free template distributed with the API (Linux)

API Subscription

Full Support. Seamless Integration. Free Updates.

When you subscribe to our APIs, you’re not just getting cutting-edge tools - you’re gaining a dedicated partner committed to your success. Every subscription includes:

  • Comprehensive Documentation – Easy-to-follow, regularly updated, and project-focused.

  • Personalized Training – Get up to speed quickly with tailored guidance.

  • Direct Expert Support – One-on-one help to solve issues fast and effectively.

  • Guaranteed Compatibility – We’ll work with you to ensure the APIs run smoothly on your system.

  • Free Updates – All improvements and new features are yours at no extra cost for the duration of your subscription.

Your workflow matters. I’ll make sure everything runs reliably, so you can focus on results - not troubleshooting.

Academic (Individual) subscription

30-days: £9.99

Terms & Conditions for Academic Software License

Fill the form for subscribing this API.

Fill and submit this form before subscribing this API. Our team will then coordinate with you for the installation of the API and for generating the license for your machine.

We will not be able to sell you the API if the Terms & Conditions are not accepted upon submission of this form.

1-year: £39.99

3-years: £79.99

Academic/Individual Subscription

1-year: £99.9

Terms & Conditions for Industry Software License

Available with Business subscription

We have a comprehensive pre-processor and post-processor GUI for our APIs. The pre-processor imports mesh data and generates the input data for the API. The post-processor enables the visualisation of results. More details for the GUI can be found here.

A 36-month business subscription includes one complimentary GUI license. Even with multiple API licenses subscribed, the customer is eligible for only one free GUI license.

Small Business subscription

(revenue less or equal than $1,000,000.0 USD/year)

Large Business subscription

(revenue greater than $1,000,000.0 USD/year)

Fill the form for subscribing this API.

Fill and submit this form before subscribing this API. Our team will then coordinate with you for the installation of the API and for generating the license for your machine.

We will not be able to sell you the API if the Terms & Conditions are not accepted upon submission of this form.

3-years: £199.9

1-year: £199.9

3-years: £399.9

Business Subscription