Model Formulation for the Rupture Mechanism of Syringes Produced in A Typical Syringe Plant

Abstract— In a previous research work, attempt was made to improve upon the productivity of the syringe plant of First Medical & Sterile Product, Port Harcourt, Nigeria, by using time and motion study. The innate requirement for quality assurance and integrity of the manufactured products medically when put to use sensitize the consciousness of the researchers to delve into the design and rupture mechanism of the syringe barrel. Two design models were proposed. These are cylindrical barrel with flat ends and cylindrical barrel with hemispherical ends. Stress and force analysis projected the cylindrical barrel with flat ends as more suitable design on the basis of crack propagation, bursting or mode of failure by rupture. For the cylindrical barrel, force equilibrium to prevent bursting in transverse direction was confirmed to be 5.4711N while force equilibrium to stop bursting in the longitudinal direction was 89.01N. The force equilibrium was established on the basis of equality of the stress force and pressure force of the enclosed fluid.

The results of cylindrical barrel with hemispherical ends was catastrophic in the sense that equilibrium of stresses and forces to avoid crack propagation or busting could only hold in the longitudinal direction. So to say that, equilibrium of stresses and forces failed in transverse directions, resulting in longitudinal rupture or bursting of the cylinder. The numerical values of the stress force and fluid pressure force being 99.95N and 94.48N respectively.

To this end the design and rupture mechanism of the syringe barrel of First Medical & Sterile Product had been established with cylindrical barrel having flat ends being the approved design.