• • Under mass-inertial confinement (mass ratio >45:1), composite propellant (AP/Al/RDX/binder) exhibits burning with maximum pressure <50 MPa and reaction fraction <1%, whereas PBX (HMX/CL-20) undergoes violent explosion with pressure up to 2 GPa and reaction fraction >50%, highlighting material-specific response critical for munition safety.
• • Mass-inertial confinement enhances early pressurization by suppressing cavity growth; when pressure remains below cylinder yield strength (1090 MPa for 30CrMnSiA steel), confinement dominates pressurization, but above yield, combined inertial and structural effects lead to cylinder rupture and mass block upsetting, dictating structural response thresholds.
• • The experimental setup enables simultaneous PDV measurement of cylinder radial expansion and mass block axial velocity, providing time-resolved data on reaction growth; for propellant, no cylinder deformation occurred, while for PBX, significant radial expansion and eventual breakup were observed, correlating with violence levels.
• • Reaction violence is governed by the interplay of material reactivity and confinement: propellant's low reactivity (<1% reaction) under strong confinement remains benign, whereas PBX's high energy release (>50% reaction) overcomes confinement, leading to catastrophic failure—emphasizing the need for material-specific risk assessment in explosive containment design.