A suitable procedure for determining the fatigue threshold of human cortical bone tissue under mode I loading

Area of Science:

• Biomaterials Science
• Mechanical Engineering
• Orthopedic Research

Background:

• Human cortical bone exhibits complex fatigue behavior crucial for skeletal integrity.
• Understanding fatigue fracture mechanics is vital for designing long-lasting implants and prosthetics.

Purpose of the Study:

• To characterize hydrated human cortical bone under Mode I fatigue-fracture.
• To determine coefficients of the modified Paris law and the fatigue threshold.
• To validate experimental procedures using a cohesive zone model.

Main Methods:

• High-cycle fatigue tests using the double cantilever beam method under displacement control.
• An equivalent crack-length-based procedure for data reduction.
• Formulation and application of a cohesive zone model for high-cycle fatigue.

Main Results:

• Successfully identified coefficients for a modified Paris law specific to human femoral cortical bone.
• Determined the strain energy release rate at the fatigue threshold.
• Validated the experimental procedure and data reduction method.

Conclusions:

• The proposed modified Paris law accurately represents the fatigue behavior of human femoral cortical bone.
• The study provides critical parameters for predicting bone fatigue life.
• The cohesive zone model effectively validates the experimental approach.