Carlos Eduardo Nunes da Costa

Análise robusta da Hidroformação de tubos numa matriz com secção transversal quadrada

(Co- supervision) 28/07/2021

This master thesis deals with a statistical analysis of the hydroforming of tubes in a square cross-section die, aims to evaluate the influence of the variability of the parameters of the material and the hydroforming process on the reduction of the thickness and bulged height at the corner of the squared section of the tube.

 Eduardo Filipe Soares Carvalheiro

Estratégias de identificação de parâmetros constitutivos de chapas metálicas

(Co-supervision)  15/07/2021

The objective of this work is to develop strategies for the identification of anisotropic criteria parameters for metal sheets, using a reduced number of experimental tests. In this research, several parameter identification strategies have been developed to generate the artificial values of anisotropy coefficients and yield stresses that replace the experimental ones, for several directions. These strategies were applied for a set of materials know by their high anisotropy behavior. The main goal was to attempt to generalize the developed identification strategies for effective assessment of their robustness.

Houssem Ben Hamida

Identification du Comportement Elastoplastique des Couches Minces par Simulation Numérique Supportée par Nanoindentation Instrumentée

25/01/2020

This master thesis deals with the parameter identification and the FEA of the nanoindentation test carried out on thin films. In this work, the nanomechanical properties, such as Young modulus and hardness were determined using inverse analysis (IA) which was based on the combination of Artificial Neural Network method (ANN), experimental nanoindentation test results and finite element simulation of the indentation using Abaqus code. The experimental nanoindentation tests have been carried out with the collaboration of colleagues from the research group “B. materials and processes” at CEMMPRE at University of Coimbra. In my opinion, the involvement in this kind of research is likely some proofs of the multidisciplinary nature of my research works grounded in mechanical engineering area.

 Mohamed Tlijani

Évaluation Expérimentale et Numérique du Comportement d’un Tube sous Compression Latérale

16/01/2015

Summary:

The aim of this research is to identify the material parameters of a steel tube using an inverse method. This was achieved by analyzing the results of lateral compression tests conducted with a spherical indenter.

Experimental lateral compression tests on tubes were conducted, and the obtained experimental results were analyzed. An inverse identification algorithm was developed to determine the mechanical parameters of the tube, considering both isotropic and anisotropic behavior models. Specifically, a finite element model was built using the ABAQUS code and coupled with the optimization method (Gauss-Newton Method) to solve the inverse problem. Finally, the validation of this identification method was carried out by comparing the experimental results with those obtained through numerical simulation of the lateral crushing test using the identified parameters.

 Zoueghui Seifallah

Identification des Lois de Comportement à Partir des Essais d’Hydroformage des Tôles Minces    

09/11/2015

Summary:

The objective of this work is to identify the anisotropic constitutive laws from hydraulic bulging tests performed with circular and elliptical dies. The materials to be characterized are anisotropic metal sheets used in sheet metal forming processes.

Numerical simulations of hydraulic bulge tests using ABAQUS the finite element code, were performed to investigate the effect of the hardening coefficient n, the consolidation coefficient k, and the anisotropy coefficients (r0, r45, and r90) on the response of different hydraulic bulge tests: using circular and elliptical dies. It was shown that the responses of these tests are sensitive to the behavior parameters to be identified. Subsequently, an analytical model was developed based on membrane theory, the relationships between geometric parameters for hydraulic bulge tests and the Hill48 yield criterion, in order to transform global quantities (pressure-height at the pole) into local quantities (stress-strain) that express the behavior of the sheets. An optimization method coupled with the analytical model was used to identify the behavior model (anisotropy and hardening parameters) of two metal sheets used in stamping: a mild steel DC04 and an AISI 304 stainless steel. Finally, to validate the relevance of the identified behavior model, numerical simulations of hydraulic bulge tests and plane tensile tests were carried out using the parameters found in the parametric identification phase as input data. The comparison between the experimental results and those calculated numerically was performed. It allows to elucidate the relevance of the identification methods used and the accuracy of the identified model to predict the behavior of the sheets studied.

Zahi Khaoula

Etude et fabrication d’un dispositif pour l’essai Erichsen

2018-2019

Project Objective:

The objective of this master's thesis is to design, develop, and implement an Erichsen test device for integration with the existing tensile testing machine in the Mechanical Engineering Department at ISSATSo de Sousse.

Abdelkhalek Abounour

Etude et conception de fabrication d’un dispositif de cintrage de tubes

2018-2019

Project Objective:

Design, develop, and implement a machine capable of bending 50mm diameter tubes with a 2mm wall thickness fabricated from AISI 314 stainless steel. This will be achieved through a combination of finite element analysis (FEA) simulation and 3D CAD design.

• Finite Element Modeling and Simulation:
  • Development of a 3D CAD model of the tube and the bending machine in a suitable software (e.g., SolidWorks).
  • FEA simulation of the bending process using software like ABAQUS to analyze stress distribution, strain, and deformation under various loading conditions (force, speed).
  • Validation of the FEA model by comparing simulated results with experimental data.
• Mechanical Design and Engineering:
  • Design of the machine's components (frame, clamping system, bending die) using SolidWorks.
  • Optimization of component geometries to minimize stress concentrations and deformations.
  • Selection of appropriate materials based on mechanical properties, environmental considerations, and cost.
• Fabrication and Assembly:
  • Creation of manufacturing drawings for the machine components.
  • Selection of suitable manufacturing processes (e.g., machining, welding).
  • Quality control of fabricated components.
  • Assembly of the complete bending machine.
• Testing and Validation:
  • Preparation of test specimens (AISI 314 tubes).
  • Conducting bending tests on the fabricated machine.
  • Measurement of critical geometric parameters of the bent tubes (e.g., bend radius, ovality).
  • Statistical analysis of test results.
  • Comparison of FEA simulations with experimental results.

This project aims to develop a high-performance tube bending machine tailored to the specific requirements of bending 50mm diameter, 2mm thick AISI 314 stainless steel tubes. Through a rigorous design, simulation, and testing process. This project will contribute to advancements in metal forming techniques and provide valuable insights into the optimization of bending processes.

Boubaker Masmoudi

Optimisation des conditions de galvanoplastie pour améliorer l'adhérence des revêtements de nickel sur les surfaces des robinets de salle de bain

2017-2018

Mohamed Komti

Modélisation, simulation et optimisation d’un siège d’avion UML

2016-2017

The technological development of structures that can adapt to different service conditions is growing in several sectors of industrial activities, such as the aerospace industry. This project focused on the study of an ULM airplane seat, in particular, we aim to optimize the seat mass by using composite materials.

This study proposes a strategy and a solution to remedy and reduce the risks of seat failures, maximize structural efficiency and robustness, as well as reduce seat mass and total manufacturing cost by using composite materials such as fiberglass and carbon fiber epoxy matrix.

In this project we used  ABAQUS finite element code to simulate the impact of loads applied to the seat in service (at the moment of contact with the ground during landing) on the mechanical behavior and resistance to damage. Sensitive, damaged and relaxed areas on the seat structure are identified from the simulation result of the Tsai-Hill criterion in order to apply a mass optimization process to achieve a viable solution by influencing the number of layers adopted in each area