CESAR is a finite element software for structural analysis designed and verified by the IFSTTAR institute (formerly known as LCPC - Central Bridges and Roadworks Laboratory). Under continuous development since 1983 in order to meet civil engineering standards, CESAR is dedicated to underground works, civil works, soils mechanics, hydrogeology and environmental challenges.
Since 2003, itech joined the software’s development team and brings its expertise in designing powerful and accessible user interfaces. Thus, the close collaboration between IFSTTAR and itech brings CESAR as a highly featured and professional software both in 2D and 3D.
CESAR implements several calculation algorithms so that non-linear analysis can be carried out in an efficient and robust manner.
CESAR comes with both simple and advanced constitutive models for soil and rock including Mohr-Coulomb, Hoek-Brown and Hardening Soil Model. User will also take high benefice from the constitutive laws lab, allowing an advanced soil behaviour modelling.
Other materials like concrete or steel are also embedded.
CESAR processes seepage analysis in saturated or non-saturated porous media. The diffusion problems are analyzed under steady- or transient state.
The results can be integrated in the total/effective stress problems. This sequential analysis is fitted for common models.
The results of a Finite Elements analysis (stresses, displacements fields) reflect the mechanical equilibrium of the model. However limit state or safety-factor analysis is often required for the design of geostructures. CESAR integrates:
The consolidation analysis is used to simulate the phenomenon of how excess pore water pressure changes with the changes in load/boundary conditions.
In CESAR, this full coupled stress-flow analysis integrates the behaviour of non-linear materials constitutive models. This process provides more accurate results than the same analysis with elastic materials or uncoupled assumptions.
CESAR computes, by means of direct integration, the response of a structure submitted to a dynamic load; it enables proceeding with a step-by-step resolution of the dynamic equilibrium equation.
Another methods consists of computing, by means of modal superposition (eigenvalues seeking is included), the response of a structure submitted to a dynamic load. Two types of problems have been considered herein:
The process in which the response of the soil influences the motion of the structure and the motion of the structure influences the response of the soil is termed as soil-structure interaction (SSI).
CESAR integrates Finite Elements families for a correct modelling of this SSI:
More, contact elements and algorithms can be associated to the shell, beam and volumes interfaces so that debonding, slipping or simple friction is correctly modeled.
Heat analysis is useful for the simulation of several phenomena in Civil Engineering: fire in tunnels, temperature elevation in a road pavement… CESAR is fitted to model several boundary conditions and heat transfers.
Easily coupled with the mechanical algorithms, the temperature gradients, results of the heat analysis, provide correct modelling of the induced stress fields.
Plasticity criteria for soils
Plasticity criteria for other materials
A numerical toolbox of constitutive models has been designed and integrated in the software CESAR-LCPC, proposing elastic laws, plasticity and hardening criteria. Thus adapted to the project context and geomaterials types, they show value added to geotechnical engineers for a better analysis of earthworks behaviour.
CESAR is equipped with a large set of CAD tools so that user feels comfortable as it is similar to his CAD software environment.
Also, because several structures are suited for parametric design, we integrate assistance for the model generation, from geometry (tunnels as example) to results analysis. Our tools are based on XML files and PYTHON scripts.
The workflow of CESAR has been designed so that user will easily have an overview of the model status: geometry, mesh, material properties, boundary conditions and loading sets.
The “Tree view” window is the heart of the model. User will see here at once all the analysis carried on the model in the “Calculation tree”. He can also access and check the properties of the model in the “Data tree”
CESAR includes a wide set of efficient meshing procedures. All the algorithms allow definition of mesh refinement by giving density of all the segments:
Finite Elements library
Analysis of the foundation behaviour influenced by the choice f the constitutive model: from elastic linear isotropic, to non-linear elastoplastic mechanism associated with anisotropic criterion
CESAR new version 6. Overview of consitutive models proposed as standard library or user-defined with a specific toolbox.
Workflow of CESAR new version 6.
Example of modelling the construction works of an embankment.