Reliability analysis of hybrid ceramic/steel gun barrels

Proceedings of the Institution of Mechanical Engineers, Part L:

DeLong

Derossett

2002

The development of residual stresses in a hybrid a-SiC lining/CrMoV steel jacket gun barrel during shrink tting of the jacket over the lining is studied using a probabilistic nite element analysis. Particular attention is given to understanding the development of the axial compressive stress in the ceramic lining, since this stress (if suf ciently 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, material and process 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, enabling determination of the cumulative distribution function for failure of the lining. The results obtained are validated using the adaptive importance sampling (AIS) method, an ef cient 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 affected to the greatest extent by the magnitude of the friction coef cient at the lining/barrel interface.

Section: Resultsmentioning

confidence: 99%

Section: Advanced Mean Value Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Proceedings of the Institution of Mechanical Engineers, Part L:

DeLong

Derossett

2002

“…Computational algorithm. The conventional displacement-based, Lagrangian-type, isothermal, transient, non-linear dynamics finite-element analysis was used in this portion of the work (Grujicic et al, 1990(Grujicic et al, , 1993(Grujicic et al, , 1995(Grujicic et al, , 2002(Grujicic et al, , 2008(Grujicic et al, , 2010b(Grujicic et al, , 2013a(Grujicic et al, , 2014dGrujicic and Cheeseman, 2014a).…”

Section: Modeling and Computational Analysismentioning

confidence: 99%

Process and product-performance modeling for mechanical fastening by flow drilling screws

International Journal of Structural Integrity

Snipes

Ramaswami

2016

Purpose – The purpose of this paper is to propose a computational approach to establish the effect of various flow drilling screw (FS) process and material parameters on the quality and the mechanical performance of the resulting FS joints. Design/methodology/approach – Toward that end, a sequence of three distinct computational analyses is developed. These analyses include: (a) finite-element modeling and simulations of the FS process; (b) determination of the mechanical properties of the resulting FS joints through the use of three-dimensional, continuum finite-element-based numerical simulations of various mechanical tests performed on the FS joints; and (c) determination, parameterization and validation of the constitutive relations for the simplified FS connectors, using the results obtained in (b) and the available experimental results. The availability of such connectors is mandatory in large-scale computational analyses of whole-vehicle crash or even in simulations of vehicle component manufacturing, e.g. car-body electro-coat paint-baking process. In such simulations, explicit three-dimensional representation of all FS joints is associated with a prohibitive computational cost. Findings – Virtual testing of the shell components fastened using the joint connectors validated the ability of these line elements to realistically account for the strength, ductility and toughness of the three-dimensional FS joints. Originality/value – The approach developed in the present work can be used, within an engineering-optimization procedure, to adjust the FS process and material parameters (design variables) in order to obtain a desired combination of the FS-joint mechanical properties (objective function).

“…To further demonstrate the full utility of the newly developed ply/lamina length-scale CMC material model (referred to hereafter as the component-level material model), the material model developed in the Derivation of the homogenized material model section is used in the current section to analyze, using a transient non-linear dynamics finite-element analysis, the structural/damage response of a prototypical gas turbine engine component, a turbine shroud, to impact by a foreign object. [31][32][33][34][35][36][37][38][39][40] Such an analysis involves the same finite-element steps (a)-(h) identified in Section II. Since most of these steps are identical to the ones presented in Section II, only the ones which had to be modified/augmented are discussed in the following subsection.…”

Section: Foreign Object Damage Of Cmc Turbine Shroudsmentioning

confidence: 99%

Multi-length-scale derivation of the room-temperature material constitutive model for SiC/SiC ceramic-matrix composites

Proceedings of the Institution of Mechanical Engineers, Part L:

Snipes

Galgalikar

et al. 2015

In the present work, multi-length-scale physical and numerical analyses are used to derive a SiC/SiC ceramic matrix composite (CMC) material model suitable for use in a general room-temperature, finite element-based, structural/ damage analysis of gas turbine engine components. Due to its multi-length-scale character, the material model incorporates the effects of fiber/tow (e.g. the volume fraction of the filaments, thickness of the filament coatings, decohesion properties of the coating/matrix interfaces, quality, as quantified by the Weibull distribution parameters, of the filament, coating, and matrix materials, etc.) and ply/lamina (e.g. the 0 /90 cross-ply vs. plain-weave architectures, the extent of tow crimping in the case of the plain-weave plies, cohesive properties of the inter-ply boundaries, etc.) length-scale microstructural/architectural parameters on the mechanical response of the CMCs. To identify and quantify the contribution of the aforementioned parameters on the material response, detailed numerical procedures involving the representative volume elements and the virtual mechanical tests are developed and utilized. The resulting homogenized turbine-engine component-level material model is next integrated into a user-material subroutine and used, in conjunction with a commercial finite element program, to analyze the foreign object damage experienced by a toboggan-shaped turbine shroud segment. The results obtained clearly revealed the role different fiber/tow and ply/lamina microstructural parameters play in the structural/damage response of the gas-turbine CMC components.