Theoretical model and parameter optimization of embryo eggshell perforation under impact

Area of Science:

• Agricultural Engineering
• Biomedical Engineering
• Animal Science

Background:

• In-ovo vaccination requires precise eggshell perforation.
• Suboptimal perforation parameters cause shell damage, impacting hatching safety.
• Minimizing mechanical damage during perforation is essential for embryo survival.

Purpose of the Study:

• To determine optimal eggshell perforation parameters for in-ovo vaccination.
• To minimize mechanical damage (hole deformation, crack propagation) during perforation.
• To evaluate the impact of perforation parameters on hatching outcomes.

Main Methods:

• Designed an impact perforation experimental device for embryo eggs.
• Established a Pogorelov-Griffith bending-fracture coupled model.
• Employed single-factor experiments, orthogonal experiments, and GA-BP neural network optimization for punch diameter (D), impact velocity (V), and impact force (F).
• Utilized a mechanical damage score (S) based on hole deviation (DI) and crack length (CL) as the primary indicator.
• Conducted simulated in-ovo manipulation experiments to assess biological impacts.

Main Results:

• Parameter influence on mechanical damage score (S) followed the order: D > V > F.
• Increased punch diameter significantly worsened hole deformation and crack propagation.
• Optimal impact velocity window identified between 2.2-2.3 m/s.
• Impact force stabilized near 1.5-1.6 N.
• GA-BP model demonstrated high predictive accuracy for S (R²=0.91, RMSE=0.02).

Conclusions:

• Recommended optimal parameters: D = 2.0 mm, V = 2.25 m/s, F = 1.6 N.
• This parameter set resulted in the lowest mechanical damage score (S), reduced dye penetration, minimal shell membrane damage, lower contamination rates, and highest hatch-of-viable.
• Mechanical damage score (S) is a viable indicator for screening low-damage perforation parameters.
• The identified parameter window provides crucial data for optimizing eggshell perforation in in-ovo vaccination.