Determination of vibration-related spinal loads by numerical simulation

Area of Science:

• Biomechanics and Ergonomics
• Occupational Health and Safety
• Computational Modeling

Background:

• Long-term exposure to whole body vibrations (WBV) poses significant health risks to the lumbar spine.
• Increasing occupational WBV exposure necessitates accurate methods to assess potential spinal injury risks.
• Understanding lumbar spine loads is critical for comparing them against spinal strength to evaluate WBV health risks.

Purpose of the Study:

• To present an approach for predicting dynamic spinal loads caused by whole body vibrations using numerical simulation.
• To develop and verify a simplified, adaptable finite-element model for predicting individual spinal loads.
• To provide a tool for quantitative assessment of spinal loads under specific occupational/clinical conditions.

Main Methods:

• Development of a simplified, linearised finite-element model of the human body, adaptable to individual anthropometry and posture.
• Reduction in complexity from a detailed nonlinear finite-element model to facilitate efficient simulation.
• Verification of the model through comparison with experimental measurements on human subjects for vertical and horizontal excitations.

Main Results:

• The simplified finite-element model accurately predicts dynamic spinal loads for individual subjects.
• Model adaptability allows for prediction of individual exposure-effect relationships.
• A novel method for eliminating local skin-accelerometer vibration influence is discussed, potentially improving model verification with bone acceleration data.

Conclusions:

• Simplified finite-element models are effective for predicting integral loading measures like spinal loads.
• Quantitative spinal load assessments can be performed for individual conditions, aiding risk evaluation.
• Linearised models are suitable for limited excitation intensities, and discrete dashpot elements are recommended for modeling energy dissipation.