Research Projects

RDFORMING

(2019-2022) FCT project: RDFORMING project: Robust Design of Sheet Metal Forming Processes to reduce Productivity Losses (Ref.: POCI-01-0145-FEDER-031243)

The research activities focused on the development of robust approach for measuring and modeling the sources of scatter in metal forming processes.

Building methodologies able to achieve robust design, where the effect of input variables uncertainty in tube hydroforming process (THF). Moreover, shape optimization of samples and constitutive parameter identification were performed using machine learning techniques (ML) as alternative to classical methods utilizing the gradient of objective function to minimize. Furthermore, new ring hoop tensile testing set up was designed and fabricated and optimized to carry out experimental tests without using any kind of lubrication. This innovation is very useful for several industries using thin-walled tubular materials (in automotive, aeronautical and nuclear industries) to characterize the mechanical behavior of tubes. Globally, the outcome of the work up today in this project are 7 publications:

01. New approach for the identification of anisotropy material parameters using hydraulic bulge tests_2022

https://doi.org/10.1088/1757-899X/1238/1/012003

02. Effect of input variables uncertainty in free tube hydroforming process_2021

https://dx.doi.org/10.25518/esaform21.2364

03. Machine Learning for Predicting Fracture Strain in Sheet Metal Forming_2022

https://doi.org/10.3390/met12111799

04. New Mandrel Design for Ring Hoop Tensile Testing_2021

https://doi.org/10.1007/s40799-021-00462-4

05. Mechanical design of ring tensile specimen via surrogate modelling

for inverse material parameter identification_2021

https://doi.org/10.1016/j.mechmat.2020.103673

06. Thermo-mechanical modelling of the Friction Stir Spot Welding (FSSW) process: Effect of the friction models on the heat generation mechanisms_2022

https://doi.org/10.1177/14644207211070965

07. Constitutive parameter identification of CB2001 yield function and its experimental verification using tube hydroforming tests_2020 https://doi.org/10.1016/j.ijmecsci.2020.105868

Forming processes and surface finishing

2. (2013-2018) DGRST project (National Project)

Forming processes and surface finishing, financed by the DGRST (in Tunisia). Mainly, I worked on two project axes: (i) metal forming by plastic deformation and (ii) advanced manufacturing processes. In this project, my activities focused on the forming of metallic materials and the experimental characterization of thin walled structures (metallic sheets and tubes). Carrying out tensile tests, sheet bulge tests, free tube hydroforming tests as essential activity for the mechanical material characterization used for parameter identification of models behaviour. I worked on the development of new geometries of samples used for mechanical testing for the characterization of anisotropic tubular materials (extruded AA6063 Aluminum tubes). Sample geometries of metallic Ring hoop tensile tests (RHTT) were optimized. In addition, ring hoop shear test was first proposed. Fixature features were also developed to vanish the friction between the ring samples and the fixture to directly determine the material properties during RHTT. A Patent was published related to this innovative research work.

MT4MOBI

3. (2013-2014) FCT project: Ref.: CENTRO -07-0224 -FEDER -002001(MT4MOBI)

Portuguese Foundation for Science and Technology (FCT), in the scientific area of Mechanical Engineering, in the scope of the project QREN Mais Centro SCT_2011_02_001_4637_MT4MOBI-Materials and Technologies for Greener Manufacturing & Products Applied to Mobility, working at University of Coimbra.

My research activities focused on the development and implementation of methodologies for the identification of constitutive models in the numerical simulation of sheet metal forming and tube hydroforming processes. Two distinct strategies for the parameter identification of constitutive equations have been developed. The first identification procedure uses strictly the minimum experimental data required for the constitutive parameter identification. The second strategy takes into account all the experimental data available for given material, being the over- constrained problem solved by minimization of a cost function. In this research, I proposed innovative strategies for parameter identification of materials. The realized work has a major interest from the point of view of research activity and crucial importance for the industrial applications for the identification of advanced yield criteria for sheet metal forming and tube hydroforming processes. The work was concluded by the publication of (two) 2 articles published in Q1 journals: International Journal of Mechanical Sciences:

Mechanical characterization and constitutive parameter identification of anisotropic tubular materials for hydroforming applications

(https://doi.org/10.1016/j.ijmecsci.2015.09.017 ), 30 citations

Influence of the characteristics of the experimental data set used to identify anisotropy parameters

(https://doi.org/10.1016/j.simpat.2015.02.007 ), 15 citations.

CbIMaSMef

4. (2008) Project CbIMaSMef (bilateral Scientific Project: Tunisia/Portugal) : 6/TP/08

Member of the bilateral Scientific Research project between University of Monastir, Tunisia and University of Coimbra, Portugal, entitled:” Constitutive behaviour identification methods applied for sheet metal forming”:

Reference: 6/TP/08

NuSiMOpTiMef

5. (2006) Project NuSiMOpTiMef (bilateral Scientific Project: Tunisia/Prorugal) Ref.: 1/04/TP

Member of the bilateral Scientific Research project between University of Monastir, Tunisia and University of Coimbra, Portugal, entitled: “Numerical simulations and optimization methods for sheet metal forming”:

Reference: 1/04/TP.

CMCU

6. (2001) Project CMUC (bilateral Scientific Project: Tunisia/France) Ref.: 3/01/FR

Member of Research project (CMCU: Comité Mixte de Coopération Universitaire) between (LGM/ENIM) Tunisia and (LASMIS/U.T Troyes) France.