Probabilistic finite element analysis of residual stress formation in shrink-fit ceramic/steel gun barrels

Abstract

The development of residual stresses in a hybrid α-SiC-lining/CrMoV-steel jacket gun barrel during shrink fitting of the jacket over the lining is studied using a probabilistic finite element analysis. A particular attention is given to understanding the development of the axial compressive stress in the ceramic lining since this stress (if sufficiently high) can prevent lining failure caused by formation and growth of circumferential cracks near the barrel ends. To quantify the effect of variability in various design, materials, and processing parameters on the magnitude and the distribution of the axial residual stress, a probabilistic structural analysis approach, known as the Advanced Mean Value (AMV) method, is used which enables determination of the cumulative distribution function for failure of the lining. The results obtained are validated using the Adaptive Importance Sampling method, an efficient direct statistical sampling technique. Lastly, the corresponding sensitivity factors which quantify the effect of variability in each parameter on the magnitude of axial residual stresses in the ceramic lining are computed. The results indicate that the loss of the compressive axial stress in the lining near the barrel ends is to a greatest extent affected by the magnitude of the friction coefficient at the lining/barrel interface.

Reliability analysis of hybrid ceramic/steel gun barrels

“…3a–c, respectively. These results are obtained using the combined thermal/mechanical finite element analysis of the shrink‐fit process presented in our recent work, 19 the mean values of the materials properties listed in Table 2 and the steel‐jacket shrink‐fit heating temperature of 973 K. For brevity, details of this finite element analysis are not presented in the present paper. It should be noted that only the results pertaining to one fifth of the barrel length (the fifth adjacent to the breech end) are displayed in Fig.…”

“…The residual stresses displayed in Fig. 3a–c are introduced, as initial stresses, in the present finite element analysis of the development of thermal stresses in gun barrels during single‐shot and burst‐firing events using a SIGINI Abaqus User Subroutine 19 …”

“…In the initial condition, the ceramic lining and the steel jacket are both taken to contain residual stresses introduced during the shrink‐fit process, Fig. 3a–c,[link] and to be both at room temperature. As time progresses during a firing event, differences in temperatures and thermal expansion coefficients of the ceramic lining and the steel jacket give rise to the formation of thermal stresses.…”

“… Distributions of (a) the axial σ zz ;(b) the radial σ rr ; and(c) the circumferential σ θθ residual stresses in the hybrid ceramic/steel gun barrel induced by a shrink‐fit process 19 …”