Finite Element Explosion Simulation Using Ambient Elements
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Solution Overview
Problem
Current finite element analysis methods for simulating fluid-structure interaction due to explosions require very fine meshes and small time-steps, leading to excessively long computation times and decreased productivity.
Innovation Solution
The method involves creating a finite element analysis model with a single layer of ambient elements between the blast source and structure, using empirical formulas like the Friedlander equation to determine blast pressure and nodal velocities, which allows for boundary conditions to be specified, reducing the need for fine fluid meshes and decreasing computation time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a very fine FEA mesh is used to capture the behavior of the blast wave, then the simulation accuracy is improved, but the computation time becomes excessively long
Solution Approach 1:
The patent extracts the blast wave propagation physics from the full fluid-structure interaction domain and applies it as a boundary condition on the structure surface. By using the Friedlander equation to compute blast pressure and applying it as a time-dependent pressure boundary condition, the simulation eliminates the need for fine fluid meshes while maintaining accuracy in capturing blast wave effects on the structure.
Solution Approach 2:
The patent introduces an intermediary approach by using the Friedlander equation as a mediator between the blast source and the structure. This empirical equation serves as a bridge that translates blast source characteristics into boundary conditions, avoiding the need to directly simulate the complex fluid dynamics in the blast wave propagation zone.
2Measurement precision
If a very fine FEA mesh is used to capture the blast wave behavior, then the solution accuracy is improved, but the number of solution cycles increases
Solution Approach 1:
The patent extracts the essential blast wave characteristics (pressure-time history) from the complex fluid dynamics and applies them directly as boundary conditions. This extraction approach maintains solution accuracy for the structure response while dramatically reducing the number of time steps and solution cycles required, as the fine temporal resolution is only needed for the boundary condition application, not for the entire domain.
3Reliability
If the time-step is reduced to meet explicit time integration requirements, then the simulation stability is improved, but the computation time increases
Solution Approach 1:
The patent applies local quality by concentrating the fine temporal resolution only where needed - in the boundary condition application at the structure surface - rather than throughout the entire domain. The Friedlander equation provides the precise time-dependent pressure history at the boundary, allowing the bulk of the domain to use coarser time stepping while maintaining overall stability and accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces computation time for simulating fluid-structure interaction during explosions, enhancing user productivity by simplifying the simulation process and minimizing the number of solution cycles required.
Implementation Method 1
The boundary conditions comprise pressures and nodal velocities that are determined from the empirical formula (e.g., Friedlander equation) of the blast source
Data Source
AI summary
Systems and methods of simulating an explosion in time-marching finite element analysis are disclosed in the present invention. A method is configured for increasing user (e.g., engineer or scientist) productivity by reducing computation time of simulating fluid-structure interaction due to an explosion. The method comprises a creation of a finite element analysis model that includes structure, surrounding fluid, a blast source of the explosion and a single layer of ambient elements each having a segment representing a boundary of the fluid facing the blast source. Each ambient element is associated with a particular finite element representing the fluid at the boundary. The ambient elements are configured to be situated between the blast source and the structure such that the simulation can be carried on a set of boundary conditions specified thereon. The boundary conditions comprise a set of nodal velocities that are determined from the empirical formula (e.g., Friedlander equation).