• Title/Summary/Keyword: autofrettage process

Search Result 29, Processing Time 0.036 seconds

Cycling life prediction method considering compressive residual stress on liner for the filament-wound composite cylinders with metal liner (금속재 라이너를 갖는 복합재 압력용기의 라이너 압축잔류응력을 고려한 반복수명 예측 방법에 대한 연구)

  • Park, Ji-Sang;Jeung, Sang-Su;Chung, Jae-Han
    • Composites Research
    • /
    • v.19 no.1
    • /
    • pp.22-28
    • /
    • 2006
  • In manufacturing process of composite cylinders with metal liner, the autofrettage process which induces compressive residual stress on the liner to improve cycling life can be applied. In this study, a finite element analysis technique is presented, which can predict accurately the compressive residual stress on the liner induced by autofrettage and stress behavior after. Material and geometrical non-linearity is considered in the finite element analysis, and the Von-Mises stress of a liner is introduced as a key parameter that determines pressure cycling life of composite cylinders. Presented methodology is verified through fatigue test of liner material and pressure cycling test of composite cylinders.

Increments of Elastic Lad Carrying Capacity of Compound Cylinder by Using Modified-Shrink-Fit Method (修正죔맞춤 방법 을 이용한 複合圓통 의 彈性負荷能力 의 증대)

  • 정성종;홍창선
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.7 no.3
    • /
    • pp.335-343
    • /
    • 1983
  • Modified-Shrink-Fit(MSF) method of compound cylinder is studied to increase elastic load carrying capacity (ELCC) of pressure vessel. The autofrettage and the shrink-fit processes are used to study the MSF process. Theoretical analyses based on the Tresca yield criterion, Hencky's total strain theory and elastic linearly strain-hardening material are carried out to derive closed form solutions. Experimental results are compared with theoretical results with various diameter ratios between outer (SM45C) and inner (SM20C) bloc cylinder. For various diameter ratios, increments of ELCC have errors in strains vs. internal loading pressures between experimental and theoretical results. But experimental results show good agreements with theoretical results in reyield pressurizing state. The increments of ELCC of compound cylinder manufactured by the MSF process is proved by measuring the residual stresses.

Development of an Automated Design System of CNG Composite Vessel using Steel Liner Manufactured by D.D.I Process (D.D.I 공정으로 제조된 금속라이너를 이용한 CNG 복합재 압력용기의 설계 자동화 시스템 개발)

  • Kim, Eui-Soo;Kim, Ji-Hoon;Park, Yoon-So;Kim, Chul;Choi, Jae-Chan
    • 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.

Elasto-plastic Analysis of a hydrogen pressure vessel of Composite materials (복합재료 수소 압력용기의 탄소성 해석)

  • Do, Ki-Won;Han, Hoon-Hee;Ha, Sung-Kyu
    • Proceedings of the KSME Conference
    • /
    • 2008.11a
    • /
    • pp.275-280
    • /
    • 2008
  • To improve the durability of a hydrogen pressure vessel which is applied high-pressure, it needs the autofrettage process which induces compressive residual stress in the Aluminum liner. This study presents the elasto-plastic analysis to predict the behavior of structure accurately, and the Tsai-Wu failure criterion is applied to predict failure of pressure vessel of Aluminum liner and composite materials. Generally, plastic analysis is more complex than elastic analysis and has much time to predict. To complement its weakness, the AxicomPro(EXCEL program), applied radial return algorithm and nonlinear classical laminate theory (CLT), is developed for predicting results with more simple and accurate than the existing finite element analysis programs.

  • PDF

A Study on Analysis Method to Evaluate Influence of Damage on Composite Layer in Type3 Composite Cylinder (Type3 복합재료 압력용기의 복합재층 손상에 따른 영향성 평가를 위한 해석기법에 관한 연구)

  • Lee, Kyo-Min;Park, Ji-Sang;Lee, Hak-Gu;Kim, Yeong-Seop
    • Composites Research
    • /
    • v.23 no.6
    • /
    • pp.7-13
    • /
    • 2010
  • Type3 cylinder is a composite pressure vessel fully over-wrapped with carbon/epoxy composite layers over an aluminum liner, which is the most ideal and safe high pressure gas container for CNG vehicles due to the lightweight and the leakage-before-burst characteristics. During service in CNG vehicle, if a fiber cut damage occurs in outer composite layers, it can degrade structural performance, reducing cycling life from the original design life. In this study, finite element modeling and analysis technique for the composite cylinder with fiber-cut crack damage is presented. Because FE analysis of type3 cylinder is path dependant due to plastic deformation of aluminum liner in autofrettage process, method to introduce a crack into FE model affect analysis result. A crack should be introduced after autofrettage in analysis step considering real circumstances where crack occurs during usage in service. For realistic simulation of this situation, FE modeling and analysis technique introducing a crack in the middle of analysis step is presented and the results are compared with usual FE analysis which has initial crack in the model from the beginning of analysis. Proposed analysis technique can be used effectively in the evaluation of influence of damage on composite layers of type3 cylinder and establish inspection criteria of composite cylinder in service.

A Study on Filament Winding Process of A CNG Composite Pressure vessel (CNG 복합용기의 필라멘트 와인딩 공정에 관한 연구)

  • Kim, C.;Kim, E. S.;Kim, J. H.;Choi, J. C.;Park, Y. S.
    • 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.

  • PDF

A Study on filament Winding Process of A CNG Composite Pressure Vessel (필라멘트 와인딩 압력용기의 최적설계와 CNG자동차 연료 충진용기 개발)

  • Kim, Eui-Soo;Kim, Ji-Hoon;Park, Yoon-So;Kim, Chul;Choi, Jae-Chan
    • 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.

  • PDF

Analysis of Steel/composite Cylinder by GUI Program (GUI를 이용한 특수강/복합재 이중구조 후육실린더 해석)

  • Kim, Chi-Wan;Kim, Wie-Dae
    • Composites Research
    • /
    • v.25 no.4
    • /
    • pp.126-132
    • /
    • 2012
  • It is useful to have a quick analysis program in early design process for feasibility studies of composite cylinder because it takes long time and is not cost effective by commercial programs. In this paper, a GUI program is developed to calculate the stress distribution in a fast manner with the properties, the orientation angle and the stacking sequence of composite material using LabVIEW. The stress distributions of an autofrettaged cylinder and a composite cylinder with internal pressure are compared with the results by MSC Nastran/patran. The stress distribution of steel/composite cylinder is compared with the values of existing studies, and is proved. Furthermore, by calculating the stress distribution of an autofrettaged steel/composite cylinder, the stress distribution is estimated, and the program will be useful in an early design phase for feasibility studies.

Suggestions for Safety Improvement of CNG Bus Based on Accident and Failure Analysis (CNG버스 사고원인 분석에 근거한 안전성 향상 방안에 대한 연구)

  • Yoon, Jae-Kun;Yoon, Kee-Bong
    • Journal of the Korean Institute of Gas
    • /
    • v.12 no.2
    • /
    • pp.69-76
    • /
    • 2008
  • Three failure cases of CNG composite vessels were reported since after January 2005. The 1st and 2nd accidents were indebted to vessel defect and installation mistake. The 3rd was caused by gas leak at pipe connections. In this paper various aspects were studied based on information of the three failure analysis, which must be improved for better safety of the CNG bus system. Overpressure region caused by vessel explosion was theoretically predicted and also assessed by PHAST program. Explosion of 120 l vessel under 20 MPa is equivalent to 1.2 kg TNT explosion. The predicted value by PHAST was more serious than theoretical one. However, actual consequence of explosion was much less than both of the predicted consequences. Since the CNG vessel was designed by the performance based design methodology, it is difficult to verify whether the required process and tests were properly conducted or not after production. If material toughness is not enough, the vessel should be weak in brittle fracture at early in the morning of winter season since the metal temperature can be lower than the transition temperature. If autofrettage pressure is not correct, fatigue failure due to tensile stress during repeated charging is possible. One positive aspect is that fire did not ocurred after vessel failure. This may be indebted to fast diffusion of natural gas which hindered starting fire.

  • PDF