Objectives

This work can be divided into four different objectives:

  • Study of the propagation of stress waves;
  • Automatic model creetion in ABAQUS/CAE using Python;
  • Undertand the impact of different interlayer interfaces on stress wave propagation;
  • Apply optimisation algorithms to solve for maximum protection to weight ratio.
  • Stress Wave Validation

    This step was needed to be performed in order to validate theoretical stress wave speed with the one calculated in ABAQUS/CAE. Both elastic and plastic stress wave speeds were validated according to the time a certain stress pulse took to travel a number of finite elements.

    ABAQUS/CAE - Python Interface

    Replacing manual input with a python script significantly incresed testing and simulation productivity. Such script would command the whole model generation procedure, submit simulation and save/record output data. Available Input parameters include:

  • Plate Length (mm)
  • Plate Width (mm)
  • Number of Plates/Layers
  • Plates Thickness (mm)
  • Projectile Length (mm)
  • Projectile Diameter (mm)
  • Projectile Mass (kg)
  • (Image from "Abaqus Scripting User’s Manual, Version 6.11. 2011.")

    Optimisation Algorithm

    Using the ABAQUS/CAE Python interface, a script was written not only to make the model generation effortless, but also to command a series of iterations on a Particle Swarm Optimisation algorithm. ABAQUS would load random configurations, simulate them, generate output data such as weight and maximum stress and slowly converge to acceptable solutions.

    Project Gallery

    A compilation of pictures relevant for this dissertation including ABAQUS/CAE model pictures and charts.

    Conclusion

    A Python script is a very powerful tool and enables the user to effortlessly change a multitude of parameters used in the ballistic model configuration. The optimisation procedure not only was successfully implemented, but it was also possible to enhance its performance! The front plate absorbs a bigger amount of energy under the form of plastic strain. The interlayer plate absorbs some of the energy under the form of elastic strain. The tested configurations returned solutions where Place C absorbed the least ammount of energy.

    ABAQUS/CAE

    Finite Element Analysis; CAE

    Python Programming

    Scripts and Algorithms

    Optimisation

    Automation of Processes and application of Particle Swarm Optimisation Algorithm.

    Data Processing

    Process ABAQUS/CAE output data through MATLAB scripts to create plots, charts and data reports.

    Autonomy

    Taking iniative to study, develop and test different ideas on my own.

    Problem Solving

    Using tools I learned throught my studies to search and study new possible solutions.