JAMES WU
DESIGN ENGINEER
08 / Research / Medical engineering / FEA

How much lighter can a jaw implant be?

A lighter TMJ implant assessed through mesh convergence, fatigue and modal analysis rather than a single stress plot.

PROJECTTMJ Implant Optimisation
INDEPENDENT WORKSimulation and optimisation
CONTEXTIndependent project
Engineering study
Finite element mesh of a mandibular implant mounted to a jaw modelInspect full-size image ↗
FIG. 01The implant and jaw model prepared for finite-element analysis.
01 / OVERVIEW

The project in a minute.

THE OUTCOME

In simulation, the Ti-6Al-4V design reduced mass by 44.6% while meeting the assessed fatigue and modal targets.

What supports this? ↓
The challenge
Reduce implant mass while keeping strength, fatigue life and resonance risk within a defensible engineering envelope.
Independent work
Simulation and optimisation. The report records Ti-6Al-4V mass changing from 0.1314 kg in generation 1 to 0.0727 kg in generation 2, alongside static, fatigue and modal analyses.
Read this in context
Academic FEA study using simplified geometry, constraints and fatigue assumptions. The 44.6% reduction compares two designed generations, not an implanted clinical device.
01Baseline load cases02Topology & material choices03Static, fatigue & modal checks
02 / THINKING

The choices behind the result.

Open a chapter to follow the work and the choices made along the way.

01 / DESIGN

Refine the geometry using strain-energy results

Generation 1 uses core hollowing and ribs; generation 2 removes low-strain-energy material to form a fishbone-like structure. Fillets and load paths guide the revisions.

Inspect the supporting evidence ↓
02 / ENGINEERING

Check numerical behaviour before comparing designs

Global refinement exposed local stress spikes, prompting targeted refinement. The final local refinement changed stress by 2.33% and maximum deformation by 0.13% in the reported comparison.

Inspect the supporting evidence ↓
03 / ENGINEERING

Keep material and fatigue assumptions visible

The study compares 316L and Ti-6Al-4V under idealised loading. Fatigue uses fully reversed R=-1 loading and an appended S–N plateau; predicted life is model-dependent, not implant certification.

Inspect the supporting evidence ↓
METHODS USEDFEAFatigueModal analysis
03 / EVIDENCE

Results, and what they mean.

Academic FEA study using simplified geometry, constraints and fatigue assumptions. The 44.6% reduction compares two designed generations, not an implanted clinical device.

SIMULATION / BASELINE NORMALISED TO 100

44.6% less mass from the first to the second titanium design.

Baseline index100
Refined design index55.4
44.6%

Generation 1 → generation 2

Ti-6Al-4V: 0.1314 → 0.0727 kg. The same geometric reduction is reported for 316L.

2.33%

Stress change after local refinement

Reported refinement comparison; maximum deformation changed by 0.13%.

R = −1

Fatigue model assumption

Idealised fully reversed loading and a constructed S–N plateau. No clinical performance claim.

Source notes & scope 1
  1. Temporomandibular Joint Implant Design & FEApp. 3–13

    Geometry, masses, mesh strategy and fatigue assumptions; later pages report modal analysis.

Mandibular implant geometry and boundary conditions↗
FIG. 02Load cases and boundary conditions framed the optimisation.
Stress result for the optimised mandibular implant↗
FIG. 03Static stress was one of several validation views.
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