Mandibular Scaffold FEA and Optimization
Budget / Salary₹1,500–12,000
TypeFreelance project
LocationRemote
Posted43 minutes ago
# Design and Finite Element Simulation of Biodegradable Shape-Memory Polymer Composite Scaffolds for Patient-Specific Mandibular Reconstruction Following Cancer Resection
## 1. Introduction
Mandibular cancer, particularly oral squamous cell carcinoma, may require surgical removal of a portion of the lower jaw. This procedure, known as segmental mandibulectomy, can result in significant bone defects that affect chewing, speech, facial appearance and quality of life. Conventional mandibular reconstruction techniques involve bone grafts, vascularised fibular flaps and metallic fixation plates. However, mechanical mismatch, stress concentration, long-term implant retention and additional surgical interventions remain important challenges.
Biodegradable shape-memory polymers (BSMPs) offer a promising approach for developing temporary biomedical scaffolds. These materials can be programmed into a temporary shape and recover their original shape when exposed to an appropriate external stimulus, such as temperature. Unlike permanent metallic implants, biodegradable polymers can gradually degrade under physiological conditions.
The present research proposes the design and finite element simulation of a patient-specific biodegradable shape-memory polymer composite scaffold using a polycaprolactone (PCL)-based polymer reinforced with hydroxyapatite (HA). The scaffold will be designed to provide temporary mechanical support while creating a porous architecture suitable for bone tissue ingrowth. Its mechanical performance will be investigated using ANSYS Workbench.
## 2. Problem Statement
Conventional mandibular reconstruction systems primarily depend on permanent metallic fixation devices or biological bone grafts. Although these methods provide structural support, mechanical mismatch between reconstruction materials and natural bone may cause stress concentration and altered load distribution.
Biodegradable scaffolds provide an alternative approach, but their mechanical properties may decrease during degradation before sufficient regenerated bone develops. Furthermore, the combined influence of shape-memory behaviour, scaffold porosity, degradation and physiological mandibular loading requires further systematic investigation.
Therefore, this research aims to develop and computationally investigate a patient-specific biodegradable shape-memory polymer scaffold that can maintain adequate mechanical stability during early healing and progressively transfer mechanical loads to regenerated bone.
## 3. Research Aim and Objectives
**Aim:** To design and simulate a patient-specific biodegradable shape-memory polymer composite scaffold for mandibular reconstruction following cancer resection using finite element analysis.
**Objectives:**
1. To develop a three-dimensional mandibular model with a segmental resection defect using CT/CBCT imaging data.
2. To design different porous scaffold configurations using SolidWorks.
3. To develop a PCL-based shape-memory polymer composite material model reinforced with hydroxyapatite.
4. To investigate temperature-dependent shape recovery and nonlinear mechanical behaviour.
5. To evaluate stress distribution, deformation and strain under physiological mandibular loading.
6. To investigate the influence of scaffold porosity, pore size and strut thickness.
7. To simulate degradation-dependent changes in mechanical properties.
8. To investigate progressive load transfer between the degrading scaffold and regenerated bone.
9. To optimise scaffold architecture for improved mechanical stability.
## 4. Proposed Materials
The primary material will be a PCL-based biodegradable shape-memory polymer composite reinforced with hydroxyapatite.
PCL provides a biodegradable polymer base and can be engineered into shape-memory polymer networks. Hydroxyapatite is a bioactive ceramic commonly investigated in bone tissue engineering because of its similarity to the mineral component of natural bone.
The following materials will be considered:
- PCL-based shape-memory polymer: Primary scaffold material.
- PCL/HA composite: Proposed bioactive composite.
- Conventional PCL: Reference material.
- Cortical and cancellous bone: Supporting anatomical materials.
- Regenerated bone: Material representing progressive bone ingrowth.
The shape-memory behaviour, thermal transition, mechanical properties and degradation characteristics will be determined experimentally before final numerical implementation.
## 5. Research Methodology
The research will be conducted in the following stages.
### Stage I: Three-Dimensional Anatomical Modelling
An anonymised CT/CBCT scan of a human mandible will be obtained with appropriate ethical approval. The mandibular anatomy will be reconstructed using 3D Slicer or Mimics. Cortical bone, cancellous bone and the segmental resection region will be identified. A healthy mandibular model and a cancer-resection model will be developed for comparative investigation.
### Stage II: CAD Design of Porous Scaffolds
Different scaffold geometries will be developed in SolidWorks to fit the mandibular defect. Four configurations will be considered: regular grid, honeycomb, gyroid and functionally graded porous structures.
The major design variables will include pore size, porosity, strut thickness and scaffold dimensions. Preliminary porosity levels of 50%, 60%, 70% and 80% will be investigated. Pore dimensions and strut thicknesses will be selected according to manufacturing feasibility and experimental requirements.
### Stage III: Material Modelling
The PCL-based shape-memory polymer composite will be characterised using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), compression testing and shape-recovery experiments.
The required material properties will include elastic modulus, Poisson's ratio, density, thermal expansion coefficient, viscoelastic relaxation parameters and temperature-dependent mechanical behaviour.
A temperature-dependent viscoelastic constitutive model will be developed using a Generalised Maxwell representation and Prony-series parameters. A suitable custom constitutive model may be implemented through the ANSYS UserMat facility if required.
### Stage IV: Finite Element Model Development
The developed CAD geometry will be imported into ANSYS Workbench. Separate material properties will be assigned to cortical bone, cancellous bone, the biodegradable polymer composite and regenerated bone.
Appropriate contact conditions will be established between the scaffold and surrounding bone. Bonded contact will initially be considered as an idealised baseline condition, followed by interface sensitivity analysis.
Three-dimensional solid elements will be used for meshing. Local mesh refinement will be applied around scaffold struts, pore junctions and scaffold-bone interfaces. Mesh convergence will be evaluated using at least three mesh densities.
### Stage V: Static Structural Analysis
Static structural analysis will be performed to investigate scaffold performance under physiological mandibular loading conditions. Vertical and oblique occlusal loads will be considered, along with unilateral and bilateral mastication scenarios.
Anatomically justified support conditions will be applied at the mandibular condyles and relevant muscle attachment regions.
The principal output parameters will include Von Mises stress, maximum principal stress, total deformation, equivalent strain and scaffold-bone interface stress.
### Stage VI: Shape-Memory Simulation
A separate specimen model will first be developed to simulate the shape-memory process. The numerical investigation will include initial heating, mechanical deformation, cooling under constraint, removal of the programming load and subsequent thermal activation.
Shape fixity ratio, shape recovery ratio, residual deformation and stress evolution will be calculated. The numerical results will be validated against experimental shape-memory tests before applying the model to the complete mandibular scaffold.
### Stage VII: Degradation and Bone Regeneration Modelling
Degradation-dependent mechanical behaviour will be investigated through different computational stages representing initial, early, intermediate and advanced degradation.
An initial empirical relationship may be expressed as:
E(t) = E₀ exp(-kt)
where E(t) represents elastic modulus at time t, E₀ is the initial elastic modulus and k is an experimentally calibrated degradation parameter.
At each stage, scaffold properties will be updated using experimental degradation data. A corresponding regenerated-bone region will be introduced through a simplified progressive bone-ingrowth model.
The analysis will investigate stress redistribution, deformation and progressive load transfer from the degrading scaffold to regenerated bone. This computational representation will investigate mechanical load sharing rather than independently predict biological regeneration.
### Stage VIII: Optimisation and Validation
ANSYS DesignXplorer or an appropriate optimisation method will be used to optimise pore geometry, porosity and strut thickness. The objective will be to minimise excessive stress concentration and deformation while maintaining adequate structural support.
The numerical model will be validated through compression testing, cyclic mechanical testing, shape-recovery experiments and in-vitro degradation studies. Experimental load-displacement results will be compared with the corresponding numerical predictions.
## 1. Introduction
Mandibular cancer, particularly oral squamous cell carcinoma, may require surgical removal of a portion of the lower jaw. This procedure, known as segmental mandibulectomy, can result in significant bone defects that affect chewing, speech, facial appearance and quality of life. Conventional mandibular reconstruction techniques involve bone grafts, vascularised fibular flaps and metallic fixation plates. However, mechanical mismatch, stress concentration, long-term implant retention and additional surgical interventions remain important challenges.
Biodegradable shape-memory polymers (BSMPs) offer a promising approach for developing temporary biomedical scaffolds. These materials can be programmed into a temporary shape and recover their original shape when exposed to an appropriate external stimulus, such as temperature. Unlike permanent metallic implants, biodegradable polymers can gradually degrade under physiological conditions.
The present research proposes the design and finite element simulation of a patient-specific biodegradable shape-memory polymer composite scaffold using a polycaprolactone (PCL)-based polymer reinforced with hydroxyapatite (HA). The scaffold will be designed to provide temporary mechanical support while creating a porous architecture suitable for bone tissue ingrowth. Its mechanical performance will be investigated using ANSYS Workbench.
## 2. Problem Statement
Conventional mandibular reconstruction systems primarily depend on permanent metallic fixation devices or biological bone grafts. Although these methods provide structural support, mechanical mismatch between reconstruction materials and natural bone may cause stress concentration and altered load distribution.
Biodegradable scaffolds provide an alternative approach, but their mechanical properties may decrease during degradation before sufficient regenerated bone develops. Furthermore, the combined influence of shape-memory behaviour, scaffold porosity, degradation and physiological mandibular loading requires further systematic investigation.
Therefore, this research aims to develop and computationally investigate a patient-specific biodegradable shape-memory polymer scaffold that can maintain adequate mechanical stability during early healing and progressively transfer mechanical loads to regenerated bone.
## 3. Research Aim and Objectives
**Aim:** To design and simulate a patient-specific biodegradable shape-memory polymer composite scaffold for mandibular reconstruction following cancer resection using finite element analysis.
**Objectives:**
1. To develop a three-dimensional mandibular model with a segmental resection defect using CT/CBCT imaging data.
2. To design different porous scaffold configurations using SolidWorks.
3. To develop a PCL-based shape-memory polymer composite material model reinforced with hydroxyapatite.
4. To investigate temperature-dependent shape recovery and nonlinear mechanical behaviour.
5. To evaluate stress distribution, deformation and strain under physiological mandibular loading.
6. To investigate the influence of scaffold porosity, pore size and strut thickness.
7. To simulate degradation-dependent changes in mechanical properties.
8. To investigate progressive load transfer between the degrading scaffold and regenerated bone.
9. To optimise scaffold architecture for improved mechanical stability.
## 4. Proposed Materials
The primary material will be a PCL-based biodegradable shape-memory polymer composite reinforced with hydroxyapatite.
PCL provides a biodegradable polymer base and can be engineered into shape-memory polymer networks. Hydroxyapatite is a bioactive ceramic commonly investigated in bone tissue engineering because of its similarity to the mineral component of natural bone.
The following materials will be considered:
- PCL-based shape-memory polymer: Primary scaffold material.
- PCL/HA composite: Proposed bioactive composite.
- Conventional PCL: Reference material.
- Cortical and cancellous bone: Supporting anatomical materials.
- Regenerated bone: Material representing progressive bone ingrowth.
The shape-memory behaviour, thermal transition, mechanical properties and degradation characteristics will be determined experimentally before final numerical implementation.
## 5. Research Methodology
The research will be conducted in the following stages.
### Stage I: Three-Dimensional Anatomical Modelling
An anonymised CT/CBCT scan of a human mandible will be obtained with appropriate ethical approval. The mandibular anatomy will be reconstructed using 3D Slicer or Mimics. Cortical bone, cancellous bone and the segmental resection region will be identified. A healthy mandibular model and a cancer-resection model will be developed for comparative investigation.
### Stage II: CAD Design of Porous Scaffolds
Different scaffold geometries will be developed in SolidWorks to fit the mandibular defect. Four configurations will be considered: regular grid, honeycomb, gyroid and functionally graded porous structures.
The major design variables will include pore size, porosity, strut thickness and scaffold dimensions. Preliminary porosity levels of 50%, 60%, 70% and 80% will be investigated. Pore dimensions and strut thicknesses will be selected according to manufacturing feasibility and experimental requirements.
### Stage III: Material Modelling
The PCL-based shape-memory polymer composite will be characterised using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), compression testing and shape-recovery experiments.
The required material properties will include elastic modulus, Poisson's ratio, density, thermal expansion coefficient, viscoelastic relaxation parameters and temperature-dependent mechanical behaviour.
A temperature-dependent viscoelastic constitutive model will be developed using a Generalised Maxwell representation and Prony-series parameters. A suitable custom constitutive model may be implemented through the ANSYS UserMat facility if required.
### Stage IV: Finite Element Model Development
The developed CAD geometry will be imported into ANSYS Workbench. Separate material properties will be assigned to cortical bone, cancellous bone, the biodegradable polymer composite and regenerated bone.
Appropriate contact conditions will be established between the scaffold and surrounding bone. Bonded contact will initially be considered as an idealised baseline condition, followed by interface sensitivity analysis.
Three-dimensional solid elements will be used for meshing. Local mesh refinement will be applied around scaffold struts, pore junctions and scaffold-bone interfaces. Mesh convergence will be evaluated using at least three mesh densities.
### Stage V: Static Structural Analysis
Static structural analysis will be performed to investigate scaffold performance under physiological mandibular loading conditions. Vertical and oblique occlusal loads will be considered, along with unilateral and bilateral mastication scenarios.
Anatomically justified support conditions will be applied at the mandibular condyles and relevant muscle attachment regions.
The principal output parameters will include Von Mises stress, maximum principal stress, total deformation, equivalent strain and scaffold-bone interface stress.
### Stage VI: Shape-Memory Simulation
A separate specimen model will first be developed to simulate the shape-memory process. The numerical investigation will include initial heating, mechanical deformation, cooling under constraint, removal of the programming load and subsequent thermal activation.
Shape fixity ratio, shape recovery ratio, residual deformation and stress evolution will be calculated. The numerical results will be validated against experimental shape-memory tests before applying the model to the complete mandibular scaffold.
### Stage VII: Degradation and Bone Regeneration Modelling
Degradation-dependent mechanical behaviour will be investigated through different computational stages representing initial, early, intermediate and advanced degradation.
An initial empirical relationship may be expressed as:
E(t) = E₀ exp(-kt)
where E(t) represents elastic modulus at time t, E₀ is the initial elastic modulus and k is an experimentally calibrated degradation parameter.
At each stage, scaffold properties will be updated using experimental degradation data. A corresponding regenerated-bone region will be introduced through a simplified progressive bone-ingrowth model.
The analysis will investigate stress redistribution, deformation and progressive load transfer from the degrading scaffold to regenerated bone. This computational representation will investigate mechanical load sharing rather than independently predict biological regeneration.
### Stage VIII: Optimisation and Validation
ANSYS DesignXplorer or an appropriate optimisation method will be used to optimise pore geometry, porosity and strut thickness. The objective will be to minimise excessive stress concentration and deformation while maintaining adequate structural support.
The numerical model will be validated through compression testing, cyclic mechanical testing, shape-recovery experiments and in-vitro degradation studies. Experimental load-displacement results will be compared with the corresponding numerical predictions.
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