Probabilistic structural analysis to quantify uncertainties associated with turbopump blades

Abstract

and C h r i s t o s C. Chamis N a t i o n a l A e r o n a u t i c s and Space A d m i n i s t r a t i o nLewis Research Center C l e v e l a n d , Ohio 44135 SUMMARY A p r o b a b i l i s t i c s t u d y of turbopump blades has been i n p r o g r e s s a t NASA Lewis Research Center f o r o v e r t h e l a s t 3 y e a r s . The o b j e c t i v e o f t h i s study i s t o i d e n t i f y the i n f l u e n c i n g v a r i a b l e s and q u a n t i f y t h e e f f e c t s o f u n c e r t a i nt i e s i n these v a r i a b l e s on t h e s t r u c t u r a l response of c r i t i c a l s t r u c t u r a l components. T h i s paper r e p o r t s t h e e f f e c t s of u n c e r t a i n t i e s i n two o f t h e i d e n t i f i e d v a r i a b l e s which a r e geometry and m a t e r i a l p r o p e r t i e s . The q u a n t if i e d e f f e c t s o f t h e v a r i a b l e s w i 11 p r o v i d e a more r e 1 i a b l e ground t o e v a l u a t e t h e t o l e r a n c e l i m i t s on t h e d e s i g n .A methodology based on p r o b a b i l i s t i c approach has been developed t o q u a n t i f y t h e e f f e c t s o f t h e random u n c e r t a i nt i e s . The r e s u l t s of t h i s s t u d y i n d i c a t e t h a t t h e u n c e r t a i n t i e s o n l y i n geomet r y have s i g n i f i c a n t e f f e c t s on t h e s t r u c t u r a l response.

Integrated Design Method Research on Performance and Reliability of Ship Steam Turbine

“…Its technical ideas shown in Figure I The engineering case in the ship performance and reliability integration design is given in the paper with ship steam turbine as a typical mechanical and electrical product. Strength performance design parameters are calculated based on finite element method [9,11,14,15] . The Natural frequency and each order vibration frequency of according performance unit are calculated based on the Energy method and pilkey model.…”

Probabilistic finite element analysis in heat transfer to a nuclear fuel rod bumper support

“…Chamis [14] developed a probabilistic structural analysis method using different distributions such as the Weibull, normal, log-normal, etc., distributions to describe the uncertainties in the structural and load parameters or primitive variables. Nagpal et al [15] presented a probabilistic study of turbopump blades of the Space Shuttle main engine (SSME). They found that random variations or uncertainties in geometry have statistically significant influence on the response variable and random variations in material properties have statistically insignificant effects.…”

Probabilistic finite element analysis in fluid mechanics

“…to describe the uncertainties in the structural and load parameters or primitive variables. Nagpal et al (1987) presented a probabilistic study of turbopump blades of the Space Shuttle Main Engine (SSME). They found that random variations or uncertainties in geometry have statistically significant influence on the response variable and random variations in material properties have statistically insignificant effects.…”