A corner joint was investigated using finite element met hod. Since the geometry along the width ... more A corner joint was investigated using finite element met hod. Since the geometry along the width of the corner joint is uniform and load does not change in that direction, the problem was assumed to be plane strain. In addition, it was assumed that the adherents (a luminum) and adhesive (epoxy resin) had linear properties. The joint was analysed under
NATO Science for Peace and Security Series C: Environmental Security, 2009
... phases are fully anisotropic. Kaddouri et al. (2006) and Madani et al. (2007) used the finite... more ... phases are fully anisotropic. Kaddouri et al. (2006) and Madani et al. (2007) used the finite element analysis to investigate the interaction between a crack and an interface in a ceramic/metal bi-material. They investigated the ...
Class II cavities are often a challenge for dentists. There are a lot of procedures that can be u... more Class II cavities are often a challenge for dentists. There are a lot of procedures that can be used in order to fill this type of cavity and also a lot of problems concerning marginal adaptation, especially when composite materials are used. The aims of this study are to ...
ABSTRACT Objectives: Numerical determinations of Stress Intensity Factors (SIFs) for a shaft unde... more ABSTRACT Objectives: Numerical determinations of Stress Intensity Factors (SIFs) for a shaft under mixed-mode load with a crack of different sizes in the connection zone between square and circular cross-sections. Methods: Linear-elastic Fracture Mechanics principles are used. The numerical analysis program used was ABAQUS CAE version 6.9-3. The shaft consists in a circular section and a square section, with a fillet connecting zone. Cracks of different lengths and different depths are modeled. The shaft is subjected to torsion and bending. The SIFs were determined using the contour integral method. Results: The stress distribution was determined and plotted, and the stress concentration effect of the notches was highlighted. Crack propagation was also performed, using the XFEM module of ABAQUS code. The computed SIFs were plotted along the crack front. Conclusions: Crack initiation and propagation matched the pattern obtained in experimental tests, thus validating the model. The results confirmed that the fillet zone between the two sections acts as a stress concentrator. The fillet radius determines the magnitude of stress concentration. Crack geometry has a significant influence on SIFs, as well as on the global stress distribution.
Page 1. Polyurethane foams behaviour. Experiments versus modeling Liviu Marsavina 1,2 a , Tomasz ... more Page 1. Polyurethane foams behaviour. Experiments versus modeling Liviu Marsavina 1,2 a , Tomasz Sadowski 2,b , Dan M. Constantinescu 3,c , Radu Negru 1,d 1 University Politehnica of Timisoara, Department of Strength of Materials, ROMANIA ...
International Journal of Non-Linear Mechanics, 2010
The influence of impregnation on mechanical properties of polyurethane foams at room temperature ... more The influence of impregnation on mechanical properties of polyurethane foams at room temperature has been experimentally evaluated in both static and impact loading conditions. The impregnation layer increases the flexural modulus and changes the foam behaviour at impact. For un-impregnated foam the energy absorbed to fracture is equal to the impact energy, while for the impregnated specimens the energy absorbed
The desire to establish a three-dimensional framework for use in analyzing problems of stable mix... more The desire to establish a three-dimensional framework for use in analyzing problems of stable mixed-mode crack propagation has received lately a considerable attention. The study of predicting crack paths under the most general possible hypotheses (three dimensions, arbitrary geometry of the body and of the crack, arbitrary loading) is an ambitious objective. Recently, Leblond [1] and Leblond et al. [2]
Page 1. Failure of polyurethane foams under different loading conditions Liviu Marsavina 1,2 a , ... more Page 1. Failure of polyurethane foams under different loading conditions Liviu Marsavina 1,2 a , Tomasz Sadowski 2,b , Dan M. Constantinescu 3,c , Radu Negru 1,d 1 University Politehnica of Timisoara, Department of Strength of Materials, ROMANIA ...
Dental onlays are restorations used to repair rear teeth that have a mild to moderate amount of d... more Dental onlays are restorations used to repair rear teeth that have a mild to moderate amount of decay. They can also be used to restore teeth that are cracked or fractured if the damage is not severe enough to require a dental crown. The use of onlays requires less tooth reduction than does the use of metal fillings. This allows dentists to conserve more of a patient's natural tooth structure in the treatment process. The aims of this study are to evaluate the biomechanical comportment of the dental onlays, by using the 3D photo elasticity method and to investigate the integrity of the structures and their fitting to the dental support. For this optical coherence tomography and micro-computed tomography were employed. Both methods were used to investigate 37 dental onlays, 17 integral polymeric and 20 integral ceramic. The results permit to observe materials defects inside the ceramic or polymeric onlays situate in the biomechanically tensioned areas that could lead to fracture of the prosthetic structure. Marginal fitting problems of the onlays related to the teeth preparations were presented in order to observe the possibility of secondary cavities. The resulted images from the optical coherence tomography were verified by the micro-computed tomography. In conclusion, the optical coherence tomography can be used as a clinical method in order to evaluate the integrity of the dental ceramic and polymeric onlays and to investigate the quality of the marginal fitting to the teeth preparations.
Page 1. Evaluation of Interlaminar Damage and Crack Propagation Through Digital Image Correlation... more Page 1. Evaluation of Interlaminar Damage and Crack Propagation Through Digital Image Correlation Method Dan M. Constantinescu 1,a , Marin Sandu 1,b , Liviu Marsavina 2,c , Radu Negru 2,d , Matei Miron 1 , Dragos Apostol 1 ...
The performance of engineering components and structures is strongly influenced by the interactio... more The performance of engineering components and structures is strongly influenced by the interaction between design, manufacture and materials. This paper presents the fracture of copper lamellas from a circular collector. The investigated circular collector, having 315 copper lamellas, is one of the main parts of an electric motor. The fracture of the copper lamellas was observed in normal operation. This
A corner joint was investigated using finite element met hod. Since the geometry along the width ... more A corner joint was investigated using finite element met hod. Since the geometry along the width of the corner joint is uniform and load does not change in that direction, the problem was assumed to be plane strain. In addition, it was assumed that the adherents (a luminum) and adhesive (epoxy resin) had linear properties. The joint was analysed under
NATO Science for Peace and Security Series C: Environmental Security, 2009
... phases are fully anisotropic. Kaddouri et al. (2006) and Madani et al. (2007) used the finite... more ... phases are fully anisotropic. Kaddouri et al. (2006) and Madani et al. (2007) used the finite element analysis to investigate the interaction between a crack and an interface in a ceramic/metal bi-material. They investigated the ...
Class II cavities are often a challenge for dentists. There are a lot of procedures that can be u... more Class II cavities are often a challenge for dentists. There are a lot of procedures that can be used in order to fill this type of cavity and also a lot of problems concerning marginal adaptation, especially when composite materials are used. The aims of this study are to ...
ABSTRACT Objectives: Numerical determinations of Stress Intensity Factors (SIFs) for a shaft unde... more ABSTRACT Objectives: Numerical determinations of Stress Intensity Factors (SIFs) for a shaft under mixed-mode load with a crack of different sizes in the connection zone between square and circular cross-sections. Methods: Linear-elastic Fracture Mechanics principles are used. The numerical analysis program used was ABAQUS CAE version 6.9-3. The shaft consists in a circular section and a square section, with a fillet connecting zone. Cracks of different lengths and different depths are modeled. The shaft is subjected to torsion and bending. The SIFs were determined using the contour integral method. Results: The stress distribution was determined and plotted, and the stress concentration effect of the notches was highlighted. Crack propagation was also performed, using the XFEM module of ABAQUS code. The computed SIFs were plotted along the crack front. Conclusions: Crack initiation and propagation matched the pattern obtained in experimental tests, thus validating the model. The results confirmed that the fillet zone between the two sections acts as a stress concentrator. The fillet radius determines the magnitude of stress concentration. Crack geometry has a significant influence on SIFs, as well as on the global stress distribution.
Page 1. Polyurethane foams behaviour. Experiments versus modeling Liviu Marsavina 1,2 a , Tomasz ... more Page 1. Polyurethane foams behaviour. Experiments versus modeling Liviu Marsavina 1,2 a , Tomasz Sadowski 2,b , Dan M. Constantinescu 3,c , Radu Negru 1,d 1 University Politehnica of Timisoara, Department of Strength of Materials, ROMANIA ...
International Journal of Non-Linear Mechanics, 2010
The influence of impregnation on mechanical properties of polyurethane foams at room temperature ... more The influence of impregnation on mechanical properties of polyurethane foams at room temperature has been experimentally evaluated in both static and impact loading conditions. The impregnation layer increases the flexural modulus and changes the foam behaviour at impact. For un-impregnated foam the energy absorbed to fracture is equal to the impact energy, while for the impregnated specimens the energy absorbed
The desire to establish a three-dimensional framework for use in analyzing problems of stable mix... more The desire to establish a three-dimensional framework for use in analyzing problems of stable mixed-mode crack propagation has received lately a considerable attention. The study of predicting crack paths under the most general possible hypotheses (three dimensions, arbitrary geometry of the body and of the crack, arbitrary loading) is an ambitious objective. Recently, Leblond [1] and Leblond et al. [2]
Page 1. Failure of polyurethane foams under different loading conditions Liviu Marsavina 1,2 a , ... more Page 1. Failure of polyurethane foams under different loading conditions Liviu Marsavina 1,2 a , Tomasz Sadowski 2,b , Dan M. Constantinescu 3,c , Radu Negru 1,d 1 University Politehnica of Timisoara, Department of Strength of Materials, ROMANIA ...
Dental onlays are restorations used to repair rear teeth that have a mild to moderate amount of d... more Dental onlays are restorations used to repair rear teeth that have a mild to moderate amount of decay. They can also be used to restore teeth that are cracked or fractured if the damage is not severe enough to require a dental crown. The use of onlays requires less tooth reduction than does the use of metal fillings. This allows dentists to conserve more of a patient's natural tooth structure in the treatment process. The aims of this study are to evaluate the biomechanical comportment of the dental onlays, by using the 3D photo elasticity method and to investigate the integrity of the structures and their fitting to the dental support. For this optical coherence tomography and micro-computed tomography were employed. Both methods were used to investigate 37 dental onlays, 17 integral polymeric and 20 integral ceramic. The results permit to observe materials defects inside the ceramic or polymeric onlays situate in the biomechanically tensioned areas that could lead to fracture of the prosthetic structure. Marginal fitting problems of the onlays related to the teeth preparations were presented in order to observe the possibility of secondary cavities. The resulted images from the optical coherence tomography were verified by the micro-computed tomography. In conclusion, the optical coherence tomography can be used as a clinical method in order to evaluate the integrity of the dental ceramic and polymeric onlays and to investigate the quality of the marginal fitting to the teeth preparations.
Page 1. Evaluation of Interlaminar Damage and Crack Propagation Through Digital Image Correlation... more Page 1. Evaluation of Interlaminar Damage and Crack Propagation Through Digital Image Correlation Method Dan M. Constantinescu 1,a , Marin Sandu 1,b , Liviu Marsavina 2,c , Radu Negru 2,d , Matei Miron 1 , Dragos Apostol 1 ...
The performance of engineering components and structures is strongly influenced by the interactio... more The performance of engineering components and structures is strongly influenced by the interaction between design, manufacture and materials. This paper presents the fracture of copper lamellas from a circular collector. The investigated circular collector, having 315 copper lamellas, is one of the main parts of an electric motor. The fracture of the copper lamellas was observed in normal operation. This
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