Model Description and Configuration

• The knee brace model consists of several solid bodies representing components such as the ratchet, screws, pawl, struts, and other critical parts. Each component's geometry and material were carefully defined for accurate simulation results.
• The assembly was configured to represent the knee brace under default parameters, allowing uniform material application and structural evaluation across the model.

2. Material Selection and Properties

• Material Chosen: 7075-T6 aluminum alloy was selected primarily for its high strength-to-weight ratio, which provides durability and minimizes weight for enhanced comfort during use.
• Mechanical Properties: The aluminum alloy exhibits a yield strength of 5.05×10^8 N/m, a tensile strength of 5.7×10^8 N/m2, an elastic modulus of 7.2×10^10 N/m2, and a Poisson's ratio of 0.33. These properties support the model's resistance to high stress and enable realistic deformation predictions under applied loads.
• The material was defined as linear elastic isotropic to simplify the analysis while accurately representing deformation behavior.

3. Loads and Fixtures

• Loading Conditions: A concentrated force of 132.4 N was applied to the faces of the brace where the knee would exert pressure during usage. This load simulates realistic stresses on the brace during weight-bearing and movement.
• Fixtures: Specific faces of the brace were fixed to replicate anchoring points during actual use. These fixtures create boundary conditions that prevent movement at specific points, thus replicating the restraint the brace would experience when strapped onto a knee.
• Reaction forces and moments were calculated at these fixtures to determine stability under load and identify potential weak points in the design.

4. Interactions Between Components

• Global Bonded Interactions: The assembly components were defined to behave as bonded entities at their contact points, simulating a fully integrated structure.
• Component Interactions: Specific free and bonded interactions were set for various parts within the assembly to ensure that elements such as the screws, ratchets, and covers maintain structural integrity without slipping under load.

5. Mesh Configuration and Quality

• Meshing Approach: A solid mesh was applied using a blended curvature-based mesh with a maximum element size of 10.7233 mm and a minimum of 0.536167 mm. The mesh was configured to prioritize high quality, yielding 305,166 nodes and 174,225 elements.
• Quality Metrics: The model's mesh achieved high quality, with 95.3% of elements having an aspect ratio below 3, ensuring accurate simulation results. The mesh quality was verified to ensure it was fine enough to capture stress gradients while maintaining computational efficiency accurately.

6. Analysis Results

• Von Mises Stress: The analysis revealed that stresses were concentrated on key load-bearing areas, with a maximum von Mises stress of 4.138×10^7N/m2 in specific nodes, which falls within the material's yield strength, indicating structural safety.
• Displacement: Maximum displacement of 0.3579 mm occurred at a particular node under load, demonstrating the brace's capability to endure strain without significant deformation, aligning with clinical expectations for knee support during flexion and extension.
• Strain Distribution: Equivalent strain ranged from 1.610×10^-9 to 5.096×10−4, concentrated at points of contact and areas under direct force, validating the structural resilience and flexibility of the design.

Stress Plot



Strain Plot



Displacement Plot



Fatigue Check Plot