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Influence of porosity on the behavior of cement orthopaedic of total hip prosthesis
Ali, Benouis,Boualem, Serier,Smail, Benbarek Techno-Press 2015 Biomaterials and Biomechanics in Bioengineering Vol.2 No.4
This paper presents three-dimensional finite element method analyses of the distribution of equivalents stress of Von Mises. Induced around a cavity located in the bone cement polymethylmethacrylate (PMMA). The presences and effect of its position in the cement was demonstrated, thus on the stress level and distribution. The porosity interaction depending on their positions, and their orientations on the interdistances their mechanical behaviour of bone cement effects were analysed. The obtained results show that micro-porosity located in the proximal and distal zone of the prosthesis is subject to higher stress field. We show that the breaking strain of the cement is largely taken when the cement, containing the porosities very close adjacent to each other.
Influence of porosity on the behavior of cement orthopaedic of total hip prosthesis
Ali, Benouis,Boualem, Serier,Smail, Benbarek Techno-Press 2015 Biomaterials and biomedical engineering Vol.2 No.4
This paper presents three-dimensional finite element method analyses of the distribution of equivalents stress of Von Mises. Induced around a cavity located in the bone cement polymethylmethacrylate (PMMA). The presences and effect of its position in the cement was demonstrated, thus on the stress level and distribution. The porosity interaction depending on their positions, and their orientations on the interdistances their mechanical behaviour of bone cement effects were analysed. The obtained results show that micro-porosity located in the proximal and distal zone of the prosthesis is subject to higher stress field. We show that the breaking strain of the cement is largely taken when the cement, containing the porosities very close adjacent to each other.
Numerical analysis of crack propagation in cement PMMA: application of SED approach
Benouis Ali,Boulenouar Abdelkader,Benseddiq Noureddine,Serier Boualem 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.55 No.1
Finite element analysis (FEA) combined with the concepts of linear elastic fracture mechanics (LEFM) provides a practical and convenient means to study the fracture and crack growth of materials. In this paper, a numerical modeling of crack propagation in the cement mantle of the reconstructed acetabulum is presented. This work is based on the implementation of the displacement extrapolation method (DEM) and the strain energy density (SED) theory in a finite element code. At each crack increment length, the kinking angle is evaluated as a function of stress intensity factors (SIFs). In this paper, we analyzed the mechanical behavior of cracks initiated in the cement mantle by evaluating the SIFs. The effect of the defect on the crack propagation path was highlighted.
Ali Benouis,Mohammed El Sallah Zagane,Abdelmadjid Moulgada,Murat Yaylacı,Djafar Ait Kaci,Merve Terzi,Mehmet Emin Özdemir,Ecren Uzun Yaylacı 국제구조공학회 2024 Structural Engineering and Mechanics, An Int'l Jou Vol.89 No.5
This study examines crack behavior within orthopedic cement utilized in total hip replacements through the finite element method. Its main goal is to compute stress intensity factors (SIF) near the crack tip. The analysis encompasses two load types, static and dynamic, applied to a crack starting from the interface between the cement and bone. Specifically, it investigates SIFs under mixed mode conditions during three activities: normal walking, climbing upstairs, and downstairs. The results highlight that a crack originating from a micro-interface under substantial loading can cause cement damage, leading to prosthetic loosening. Stress intensity factors in modes I, II, and III are influenced by the crack tip’s orientation and location in the bone cement, with a 90° orientation yielding notably higher values across all three modes.
El Sallah, Zagane Mohammed,Ali, Benouis,Abderahmen, Sahli Techno-Press 2020 Biomaterials and Biomechanics in Bioengineering Vol.5 No.1
Total hip prosthesis is used for the patients who have hip fracture and are unable to recover naturally. To de-sign highly durable prostheses one has to take into account the natural processes occurring in the bone. Finite element analysis is a computer based numerical analysis method which can be used to calculate the response of a model to a set of well-defined boundary conditions. In this paper, the static load analysis is based, by se-lecting the peak load during the stumbling activity. Two different implant materials have been selected to study appropriate material. The results showed the difference of maximum von Misses stress and detected the frac-ture of the femur shaft for different model (Charnley and Osteal) implant with the extended finite element method (XFEM), and after the results of the numerical simulation of XFEM for different was used in deter-mining the stress intensity factors (SIF) to identify the crack behavior implant materials for different crack length. It has been shown that the maximum stress intensity factors were observed in the model of Charnley.
Behavior of structures repaired by hybrid composite patches during the aging of the adhesive
Habib Achache,Rachid Zahi,Djaafar Ait Kaci,Ali Benouis 국제구조공학회 2024 Structural Engineering and Mechanics, An Int'l Jou Vol.91 No.2
The objective of this study is to analyze, using the finite element method, the durability of damaged and repaired structures under the effect of mechanical loading coupled with environmental conditions (water absorption and/or temperature). The study is based on the hybrid patch repair technique, considering several parameters based on the J integral to observe the behavior of the adhesive in transferring load from a damaged plate to the repair patch. The results clearly show that water absorption and increased temperature cause degradation of the mechanical properties of the adhesive, leading to an increase in its plasticization, which is beneficial for the assembly’s strength. However, the degradation of the adhesive’s properties due to aging in the repair results in poor load transfer from the damaged area to the patch. The findings of this study allowed the authors to conclude that the [0°]8 sequence consistently offers the best performance, with the lowest J integral values and superior crack resistance. The lowest the J integral for the [0°]8 stacking sequence is typically 3-7% lower than that of the [0/- 45/45/90]S and [0/-45/90/45]S sequences at elevated temperatures. At 60°C, the J integral increases by approximately 3-6% compared to 40°C and 20, depending on the aging duration and stacking sequences.
Study of the fracture behavior of different structures by the extended finite element method (X-FEM)
Zagane Mohammed El Sallah,Moulgada Abdelmadjid,Sahli Abderahmane,Baltach Abdelghani,Benouis Ali Techno-Press 2023 Advances in materials research Vol.12 No.4
The fracture mechanics make it possible to characterize the behavior with cracking of structures using parameters quantifiable in the sense of the engineer, in particular the stress field, the size of the crack, and the resistance to cracking of the material. Any structure contains defects, whether they were introduced during the production of the part (machining or molding defects for example). The aim of this work is to determine numerically by the finite element method the stress concentration factor Kt of a plate subjected to a tensile loading containing a lateral form defect with different sizes: a semicircle of different radii, a notch with different opening angles and a crack of different lengths. The crack propagation is then determined using the extended finite element technique (X-FEM). The modeling was carried out using the ABAQUS calculation code.
Numerical modeling of the damaged cement orthopedic in three variants of total hip prostheses
Cherfi Mohamed,Zagane Mohammed El Sallah,Moulgada Abdelmadjid,Ait Kaci Djafar,Benouis Ali,Zahi Rachid,Sahli Abderahmen 국제구조공학회 2024 Structural Engineering and Mechanics, An Int'l Jou Vol.91 No.3
Numerical modeling using the finite element method (FEM) offers crucial insights into the mechanical behavior of prostheses, including stress and strain distribution, load transfer, and stress intensity factors. Analyzing cracking in PMMA surgical cement (polymethylmethacrylate) for total hip prostheses (THP) is essential for understanding the loosening phenomenon, as the rupture of orthopedic cement is a primary cause. By understanding various failure mechanisms, significant advancements in cemented total prostheses can be achieved. This study performed a numerical analysis using a 3D FEM model to evaluate stress levels in different THP models, aiming to model damage in the orthopedic cement used in total hip arthroplasty. Utilizing ABAQUS software, FEM, and XFEM, the damage in three types of THPs-Charnley (CMK3), Osteal (BM3), and THOMPSON was modeled under stumbling loading conditions. XFEM allowed for the consideration of crack propagation between the cement and bone, while the GEARING criterion employed a user-defined field subroutine to model damage parameters. The study’s findings can contribute to improving implant fixation techniques and preventing postoperative complications in orthopedic surgery.