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Kasper, H. J.

Publications and source records attributed to Kasper, H. J..

13 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Thrust chamber life prediction

The reusable life of the Space Shuttle main engine (SSME) is influenced by the cyclic life of the regeneratively liquid cooled main combustion chamber (MCC). During an operational duty cycle the MCC liner is subjected to a large transient thermal gradient that imparts a high thermal cyclic strain to the liner hot gas wall. Life predictions of such chambers have usually been based on low cycle fatigue (LCF) evaluations. Hot-fire testing, however, has shown significant mid-channel wall deformation and thinning during accrued cyclic testing. This phenomenon is termed cyclic creep and appears to be significantly accelerated at elevated temperatures. An analytical method that models the cyclic creep phenomenon and its application to thrust chamber life prediction is presented. The chamber finite element geometry is updated periodically to account for accrued wall thinning and distortion. Failure is based on the tensile instability failure criterion. Cyclic life results for several chamber life enhancing coolant channel designs are compared to the typically used LCF analysis that neglects cyclic creep. The results show that the usable cyclic creep life is approximately 30 to 50% of the commonly used LCF life.

Kasper, H. J.↗
NASA NTRS1983

Cryogenic fluid management experiment trunnion fatigue verification

A subcritical liquid hydrogen orbital storage and transfer experiment was designed for flight in the Shuttle cargo bay. The Cryogenic Fluid Management Experiment (CFME) includes a liquid hydrogen tank supported in a vacuum jacket by two fiberglass epoxy trunnion mounts. This composite material was selected for the trunnions since it provides desirable strength, weight and thermal characteristics for supporting cryogenic tankage. An experimental program was conducted to provide material property and fatigue data for S-glass epoxy composite materials at ambient and liquid hydrogen temperatures and to verify structural integrity of the CFME trunnion supports.

Bailey, W. J.↗
NASA NTRS1982

A simplified design procedure for life prediction of rocket thrust chambers

An analytical procedure for predicting thrust chamber life is developed. The hot-gas-wall ligaments separating the coolant and combustion gas are subjected to pressure loading and severe thermal cycling. The resulting stresses interact during plastic straining causing incremental bulging of the ligaments during each firing cycle. This mechanism of plastic ratcheting is analyzed and a method using a yield surface for combined bending and membrane loading developed for determining the incremental permanent deflection and progressive thinning near the center of the ligaments. Fatigue and tensile instability are analyzed as possible failure modes. Results of the simplified analyses compare favorably with available experimental data and finite element analysis results for OFHC (Oxygen Free High Conductivity) copper. They are also in reasonably good agreement with experimental data for NARloy Z, a copper-zirconium-silver alloy developed by the Rocketdyne Division of Rockwell International.

Porowski, J. S.↗
NASA NTRS1979

Effect of low-stiffness closeout overwrap on rocket thrust-chamber life

Three rocket thrust chambers with copper liners and a thrust level of 20.9 kN were cyclically test fired to failure. Two of the liners were made from oxygen free, high conductivity (OFHC) copper and from annealed Amzirc. The milled coolant channels were closed out with a thin copper closeout over which a fiberglass composite was wrapped to provide hoop strength only. Experimental data are presented, along with the results of a preliminary analysis that was performed before fabrication to evaluate the life extending potential of a thin copper closeout with a fiberglass overwrap.

Kasper, H. J.↗
NASA NTRS1979

Some effects of cyclic induced deformation in rocket thrust chambers

A test program to investigate the deformation process observed in the hot gas wall of rocket thrust chambers was conducted using three different liner materials. Five thrust chambers were cycled to failure using hydrogen and oxygen as propellants at a chamber pressure of 4.14 MN/sq m. The deformation was observed nondestructively at midlife points and destructively after failure occurred. The cyclic life results are presented with an accompanying discussion about the types of failure encountered. Data indicating the deformation of the thrust chamber liner as cycles are accumulated are presented for each of the test thrust chambers.

Hannum, N. P.↗
NASA NTRS1978

Investigation of the effect of ceramic coatings on rocket thrust chamber life

Two cylindrical rocket thrust chamber cylinders were coated with a 0.203 mm layer of zirconium oxide using a process that employed electrodeposition of metal to a spray-coated mandrel. The cylinders were cyclically tested using hydrogen-oxygen propellants at a nominal chamber pressure of 4.14 MN/sq m to show the effect of the coating on life. Both cylinders failed prematurely due to causes unrelated to the coatings. Post destructive analysis showed no cooling passage wall deformation. Where erosion of the coating occurred, the coating thickness stabilized at 0.061 mm within 80 cycles and remained well adhered throughout the tests. The hot-gas-side metal wall temperature and the theoretical maximum effective strain were reduced by 80 and 92%, respectively, where the coating was 0.203 mm thick and by 40 and 50%, respectively, where the coating was 0.061 mm thick compared to an uncoated cylinder. The 50 and 92% reductions in maximum effective strain resulted in theoretical lives of 1900 cycles and greater than 10,000 cycles, respectively, compared to 300 cycles for the uncoated cylinder.

Quentmeyer, R. J.↗
NASA NTRS1978

Investigation of the effect of ceramic coatings on rocket thrust chamber life

Cylindrical rocket thrust chamber cylinders were coated with a 0.203 mm (0.008 in.) layer of zirconium oxide using a process that employed electrodeposition of metal to a spray coated mandrel. The cylinders were cyclically tested using hydrogen oxygen propellants at a nominal chamber pressure of 4.14 MN/sq m (600 psia) to show the effect of the coating on life. Both cylinders failed prematurely due to causes unrelated to the coatings. Post destructive analysis showed no cooling passage wall deformation. Where erosion of the coating occurred, the coating thickness stabilized at 0.061 mm (0.0024 in.) within 80 cycles and remained well adhered throughout the tests.

Quentmeyer, R. J.↗
NASA NTRS1977

Graphical method for predicting life of a rocket thrust chamber with half-hard zirconium-copper liner and electroformed nickel closeout

A method for estimating the life of a regeneratively cooled rocket thrust chamber was developed and is based on the hot-gas wall temperature and the temperature difference between the hot-gas wall and the outside surface of the closeout. This method permits a quick estimate of the life of a thrust chamber when design changes or test-cycle variations are considered. Strain range and life are presented graphically as functions of these temperature parameters for a typical high-performance rocket thrust chamber with a half-hard zirconium-copper liner and an electroformed nickel closeout.

Kasper, H. J.↗
NASA NTRS1976

Experimental and theoretical investigation of fatigue life in reusable rocket thrust chambers

During a test program to investigate low-cycle thermal fatigue, 13 rocket combustion chambers were fabricated and cyclically test fired to failure. Six oxygen-free, high-conductivity (OFHC) copper and seven Amzirc chambers were tested. The chamber liners were fabricated of copper or copper alloy and contained milled coolant channels. The chambers were completed by means of an electroformed nickel closeout. The oxidant/fuel ratio for the liquid oxygen and gaseous hydrogen propellants was 6.0. The failures in the OFHC copper chambers were not typical fatigue failures but are described as creep rupture enhanced by ratcheting. The coolant channels bulged toward the chamber centerline, resulting in progressive thinning of the wall during each cycle. The failures in the Amzirc alloy chambers were caused by low-cycle thermal fatigue. The lives were much shorter than were predicted by an analytical structural analysis computer program used in conjunction with fatigue life data from isothermal test specimens, due to the uneven distribution of Zr in the chamber material.

Hannum, N. P.↗
NASA NTRS1976

Experimental and theoretical investigation of fatigue life in reusable rocket thrust chambers

During a test program to investigate low-cycle thermal fatigue, 13 rocket combustion chambers were fabricated and cyclically test fired to failure. Six oxygen-free, high-conductivity (OFHC) copper and seven Amzirc chambers were tested. The failures in the OFHC copper chambers were not typical fatigue failures but are described as creep rupture enhanced by ratcheting. The coolant channels bulged toward the chamber centerline, resulting in progressive thinning of the wall during each cycle. The failures in the Amzirc alloy chambers were caused by low-cycle thermal fatigue. The zirconium in this alloy was not evenly distributed in the chamber materials. The life that was achieved was nominally the same as would have been predicted from OFHC copper isothermal test data.

Hannum, N. P.↗
NASA NTRS1974

Centaur Standard Shroud (CSS) full jettison test dynamic analysis

During the space power facility jettison tests, the non-domed half of the Centaur standard shroud was allowed to completely separate from its hinge connection and was caught in a horizontal catch net. A rigid body dynamic analysis that was performed to predict the half shroud prior to and after net contact is presented. Analytical predictions of the longitudinal and circumferential bending moments imposed on the half shroud by the catch net and the net pressure on the half shroud corrugated skin are also presented.

Kasper, H. J.↗