• Journal of the Korean Society of Propulsion Engineers
• /
• v.16 no.3
• /
• pp.90-96
• /
• 2012

In order to determine optimal design length of adhesive joint of a composite rocket motor case, stress analysis of joint part according to changes of adhesive length was done. Adhesive length has a range of 50 mm to 300 mm as design variables. The ratio of adhesive length without any stress gradient to initial non-stressed adhesive length was determined as evaluation criteria for selection of adhesive length, which called "stress gradient length ratio". The numerical result showed that stress gradient length ratio of joint part with adhesive length of more than 200 mm was increased very slowly with increase of adhesive length. It means that adhesive length of about 200 mm could be the optimal dimension to ensure the structural safety of joint part against internal pressure of 2,500 psi.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.18 no.3
• /
• pp.191-204
• /
• 1998

One of the key issues in acoustic emission (AE) during hydroproof test of filament-wound composite rocket motor cases is the determination of the optimal component of elastic wave to be monitored. To solve this problem, broadband ultrasonic wave was generated into a symmetrically filament-wound composite motor case, and was received at 105 different locations after the propagation through the composite case with different distances and directions. By analysis of the received signals, characteristics of elastic wave propagation such as frequency components, the maximum propagating distance, and velocity surface were investigated. This analysis was performed for two different conditions of the motor case; air-filled and hydraulically pressurized. Based on these information, the effect of hydraulic pressure on the wave propagation characteristics was investigated and furthermore, the optimal component of elastic wave for AE during hydroproof test of the motor case was successfully determined.

• Composites Research
• /
• v.14 no.6
• /
• pp.24-31
• /
• 2001

Filament wound structures such as pressure tanks, pipes and motor cases of rockets are widely used in the aerospace application. The determination of a proper winding angle and thickness is very important to decrease manufacturing difficulties and to increase structural efficiency. In this study, possible winding angles considering the slippage between a fiber and a mandrel surface are calculated using the semi-geodesic path equation. In addition, finite element analysis using ABAcUS are performed to predict the behavior of filament wound structures considering continuous change of winding angle along the dome part. The water-pressuring tests of 3rd stage motor case are performed to verify the analysis procedure. The strain gages are attached on the surface in the fiber direction. Progressive failure analysis is performed to predict the burst pressure and the weakest region of the motor case. The effect of reinforcement is also studied to increase its performance.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2004.10a
• /
• pp.278-281
• /
• 2004

The purpose of this paper is to show a reliable analytical method to predict the deflections of F/W Composite Motor Case. Structural analysis and testing of a Carbon/Epoxy Composites Motor Case for Pressure Loadings were performed. This paper presents the development of 3-D layered axi-symmetric solid element for finite element analysis. Finite element analyses were preformed considering fiber angle variation in longitudinal and thickness direction by ANSYS. The analytical results agree well with experimental results.

• Journal of Aerospace System Engineering
• /
• v.11 no.5
• /
• pp.42-49
• /
• 2017

The solid rocket motor(SRM) consists of a motor case, igniter, propellants, nozzle, insulation, controller, and driving device. The liquid rocket propulsion systems(LRPSs) cools the nozzle by the fuel and oxidizer but SRM does not cool the nozzle. The nozzle of SRM is high temperature condition and high velocity condition so occurs the erosion by combustion gas. This erosion occurs the change of nozzle throat and reduces thrust performance of rocket. The material of Rocket nozzle is minimization of erosion and insulation effect and endure the shear force, high temperature and high pressure. The purpose of this study is to investigate the erosion characteristics of solid rocket nozzles by each combustion time. Through the structure inspection of Graphite and C-C composite, identify the characteristics of the microstructure before and after erosion.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.11a
• /
• pp.664-667
• /
• 2010

Solid rocket propulsion systems are generally used for tactical missiles due to the structural and operational simplicity. Nevertheless, various kinds of design factors including outer diameter, length, weight, loading efficiency of propellant grain effects to thrust performance. Dual thrust is beneficial to range extension and terminal velocity increasement. But loading efficiency becomes low in case to obtain dual thrust performance by burning surface control. So, It is predicted to be reasonable to obtain dual thrust performance with high/low burning rate propellants. This study is on internal ballistic analysis and ground test to confirm dual thrust performance.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.1
• /
• pp.205-213
• /
• 2003

The fiber reinforced composite material is widely used in the multi-industrial field where the weight reduction of the infrastructure is demanded because of their high specific modulus and specific strength. It has two main merits which are to cut down energy by reducing weight and to prevent explosive damage preceding to the sudden bursting which is generated by the pressure leakage condition. Therefore, Pressure vessels using this composite material in comparison with conventional metal vessels can be applied in the field such as defense industry, aerospace industry and rocket motor case where lightweight and the high pressure are demanded. In this paper, for nonlinear finite element analysis of E-glass/epoxy filament winding composite pressure vessel receiving an internal pressure, the standard interpretation model is developed by using the ANSYS, general commercial software, which is verified as the accuracy and useful characteristic of the solution based on Auto LISP and ANSYS APDL. Both the preprocessor for doing exclusive analysis of filament winding composite pressure vessel and postprocessor that simplifies result of analysis have been developed to help the design engineers.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.656-660
• /
• 2002

The fiber reinforced composite material is widely used in the multi-industrial field where the weight reduction of the infrastructure is demanded because of their high specific modulus and specific strength. Pressure vessels using this composite material in comparison with conventional metal vessels can be applied in the field where lightweight and the high pressure is demanded from the defense and aerospace industry to rocket motor case due to the merits which are energy curtailment by the weight reduction and decrease of explosive damage precede to the sudden explosion which is generated by the pressure leakage condition. In this paper, for nonlinear finite element analysis of E-glass/epoxy filament winding composite pressure vessel receiving an internal pressure, the standard interpretation model is developed by using the ANSYS 5.7.1, the general commercial program, which is verified as the accuracy and useful characteristic of the solution based on Auto LISP and ANSYS APDL. Both the preprocessor for doing exclusive analysis of filament winding composite pressure vessel and postprocessor that simplifies result of analysis have been developed to help the design engineers.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.933-937
• /
• 2002

The fiber reinforced composite material is widely used in the multi-industrial field where the weight reduction of the infrastructure is demanded because of their high specific modulus and specific strength. Pressure vessels using this composite material in comparison with conventional metal vessels can be applied in the field where lightweight and the high pressure are demanded from the defense and aerospace industry to rocket motor case due to the merits which are energy cutdown the weight reduction and decrease of explosive damage preceding to the sudden explosion which is generated by the pressure leakage condition). In this paper, for nonlinear finite element analysis of E-glass/epoxy filament winding composite pressure vessel receiving an internal pressure, the standard interpretation model is developed by using the ANSYS, general commercial software, which is verified as the accuracy and useful characteristic of the solution based on Auto LISP and ANSYS APDL. Both the preprocessor for doing exclusive analysis of filament winding composite pressure vessel and postprocessor that simplifies result of analysis have been developed to help the design engineers.

• Journal of Advanced Marine Engineering and Technology
• /
• v.22 no.2
• /
• pp.139-145
• /
• 1998

Filament winding method is widely used for composite fabrications using low viscosity liquid for-mation and processing asymmetrical structures of pressure vessel pipe rocket motor case etc. The filament winding method is affected by several parameters such as pot life of process time viscosi-ty of resin filament winding temperature and schedules curing condition and post curing condi-tion of resin. To develope high functional composite materials the rotation(5, 15, 20, 30rpm) of the winding machine was controlled by D.C motor. And the wiper to give proper tension was equipped between strand and resin bath. The resin is hooked by the design wiper. The adequate cure schedule was found by DSC. NOL ring test is carried out to investigate the basic physical properties such as design technology. The void contents in filament winding is generally higher than that of the prepreg laminated plate. These high contents of void can make a crack in resin in spite of low deformation. These problem was solved by giving tension in processing. To improve the characteristics of fiber volume fraction void contents resin/fiber bonding the winding speedc is changed under constant tension. It was found that resin impregnation was not different from in fiber contents void contents at the range of 0.5~1kg tension but it was found that resin was not impregnated at the above of 1.5kg tension. In burst test a pure PE liner was failed at a nozzle part under the $14kg/\textrm{cm}^2$ pressure but a pressure vessel of CNG was failed at a cylinder part under the $200kg/\textrm{cm}^2$ pressure.