Transactions of Nanjing University of Aeronautics & Astronautics
网刊加载中。。。

使用Chrome浏览器效果最佳,继续浏览,你可能不会看到最佳的展示效果,

确定继续浏览么?

复制成功,请在其他浏览器进行阅读

Design, Analysis, Fabrication, and Test for Low‑Cost and Out‑of‑Autoclave Composite Airship Gondolas  PDF

  • ZHU Qiang 1,2
  • TONG Mingbo 1
  • XIAO Peng 2
  • LIU Chong 2
  • QIU Chen 2
  • MA Jingjing 2
  • JIN Tao 2
1. College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, P. R. China; 2. China Special Vehicle Research Institute, Jingmen 448000, P. R. China

CLC: V222

Updated:2022-07-08

DOI:10.16356/j.1005-1120.2022.03.005

  • Full Text
  • Figs & Tabs
  • References
  • Authors
  • About
CN CITE
OUTLINE

Abstract

Out-of-autoclave(OoA) processing has the advantages of low cost, light weight and environmental protection, and has become a hot spot in the field of composite materials worldwide. This paper investigates the application of OoA processing in the gondola of the AS700 civil manned airship. The production cost of gondolas is reduced by selecting low cost materials such as glass fiber, PVC foam and OoA processing. The porosity of parts is reduced and controlled at about 2% by optimizing the edge breathing of prepreg during curing. The maximum tensile strain of the glass fiber is 4 593 με; its maximum compressive strain is 3 680 με; and its maximum shear strain is 4 884 με. The maximum Von Mises stress of the foam is 0.70 MPa. These settings all meet the margin requirement of safety. Finally, the ultimate load test of the gondola is carried out to verify the safety of the gondola structure. Our study presents critical parameters for the gondola design, including load, structure, strength, and manufacturing process test, and provides certain references for the design of similar products.

0 Introduction

With the development of composite technology, composite materials have been increasingly applied to aviation structures

1-4. Autoclave forming process has been widely used in aerospace structural parts because it can produce low porosity parts by applying high pressures and well-defined thermal curing cycles5. Vacuum bag-only (VBO) is an out-of-autoclave (OoA) processing, which has advantages in low cost and parts limitation, and has attracted the interest of aerospace industry recently6-7. However, the low applied pressure of 1×105 Pa in VBO prepreg processing8 leads to parts with a relatively low fiber volume fraction and more defects in the form of voids9.

The ratio of the void volume to the material volume, commonly known as the void volume ratio or the void volume fraction, is a key parameter to characterize the quality of parts

10. Mechanical properties such as the interlaminar shear strength, material toughness and moisture uptake are greatly affected by the void content11. The increase of porosity will lead to significant deterioration of mechanical properties of parts12-13. Generally, the porosity of aerospace structural parts needs to be controlled below 2%11.

Main drivers of the porosity formation are the length of the part or its distance from the vacuum source

14, the quality of vacuum available during processing15, material characteristics such as the percentage of initial impregnation of the tow16-18, textile architecture and air permeability19-20, as well as resin characteristics21-22. Other factors such as high moisture uptake10, prepreg out time23, as well as local defects24, can also influence the final porosity content of a part produced by OoA.

Naresh et al.

25 suggested that thermo-mechanical compaction of prepregs was one of the key stages in VBO manufacturing process, and the compaction stage and the first dwell period in a cure cycle were the most critical steps, during which the elimination of voids was possible. Serrano et al.11investigated the influence of the pre-cure compaction time and cure cycle on the porosity level, and demonstrated that the pre-cure compaction played an important role in the manufacturing of “void-free” laminates. Grunenfelder et al.26emphasized the need for adequate edge-breathing in VBO cure. Yuan et al.27 found that increasing temperature platform properly was conducive to the air out before the resin gelated and the decrease of porosity of parts. Kim et al.28 pointed out that the production of high-quality parts using OoA prepreg required out-time and humidity control and/or appropriate thermal control to ensure adequate flow time and to fully impregnate the prepreg during processing. Some researchers29-30 carried out experimental studies on the influence of ambient relative humidity, vacuum level, room temperature hold time, and part length on porosity. Increased relative humidity and reduced vacuum levels both increased void contents. For the same vacuum hold times, a longer flow distance for air evacuation increased porosity and created a porosity gradient along the evacuation direction. Porosity was fully eliminated in the case of exposure to 0% relative humidity and a long (24 h) vacuum hold.

The new generation of OoA prepreg can produce parts

2431-34 with the same quality as the autoclave through VBO processing, such as sandwich panels parts33, skin panel35, space launch vehicle fairing36, aircraft cabin frame37, aft cooling duct38, the fuselage of advanced composite cargo aircraft39, etc.

Gondolas are the important part of airships, but little relevant literature has focused on them. Based on the AS700 civil manned airship, the engineering application of low-cost composites and OoA processing in the airship gondola is carried out in this paper. First, the gondola design and the finite element model analysis results are introduced. Next, the fabrication of the gondola is described. And then the test results are analyzed. Finally, the material selection and process selection for low-cost design are recommended.

1 Design

1.1 Layout

AS700 civil manned airships can be used in tourism, aerogeophysical prospecting, aerial survey, aerial photography, emergency rescue, etc. For tourism, the gondola is located in the lower abdomen of the airship and carries two pilots and eight passengers, or one pilot and nine passengers.

According to its function, the gondola can be divided into the cockpit, the passenger compartment and the fuel compartment, as shown in Fig.1. Components in the cockpit include the driver’s seats, a dashboard, the center console, the side console, the top control panel, the front windshield, etc., and the ballast system is arranged at the bottom. The passenger compartment includes passenger seats, doors and the sightseeing glass. Steel cables and wire harness channels are installed below the floor. The landing gear is arranged at the rear of the bottom. The fuel tank is arranged in the fuel compartment, and the engine and the steering system are installed on the side. The gondola is about 7.2 m long, 1.9 m wide and 2 m high. When the fuel tank is full, the total mass on the gondola is about 3 000 kg. The gondola design should meet the requirements of aesthetics and low cost except for the conventional design requirements and airworthiness provisions.

Fig.1  Layout of the gondola

1.2 Structural design

According to the general layout and load distribution of the gondola, the gondola framework structure is arranged. The gondola framework is composed of the frame (common frame and reinforcing frame), the top ring beam, the window frame, the door frame and the floor beam. The reinforcing frame adopts metal structure to bear concentrated load, and the other structures adopt foam sandwich composite structure to reduce structural weight and obtain structural stiffness. In order to facilitate molding and reduce the deformation of parts, the foam sandwich structure uses symmetrical ply

40as far as possible. The door frame and the window frame are integrated with the skin, and the sandwich structure of skin is smoothly transferred to the laminate structure of door frame and window frame. The two-component epoxy resin adhesive is used for cementation between the composite parts. The theoretical cementation gap is 1 mm and cementation is carried out at room temperature. The theoretical mass of the gondola is 340 kg.

2 Model Results and Analysis

According to the airworthiness provisions, there are nearly 30 load conditions for the gondola. They are divided into three groups:Structural mass inertia force (including overload coefficient), landing gear load and propeller load. The overload coefficient includes flight maneuver overload, gust load overload and emergency landing overload. This paper does not discuss the emergency landing conditions, but introduces three severe conditions:The combination of the maximum continuous power of the engine and the designed maneuvering conditions(load condition No.1), the landing gear horizontal landing(load condition No.2), and the landing gear sideslip landing(load condition No.3). The loads of each condition are shown in Tables 1—3. The coordinate system is shown in Fig.1, the x-axis is along the longitudinal direction of the gondola, the y-axis along the vertical direction of the gondola, and the z-axis is along the lateral direction of the gondola. The total gravity Gt includes the gravity of the gondola (3 332 N) and the gravity of the cargo carried on the gondola (29 400 N). In Table 1, the dynamic overload coefficient fd is 1.53, mass inertia force on the gondola Fd=GtfdMx1 refers to the torque in the propeller plane, and x1 refers to the local shafting parallel to the x-axis with the propeller loading point as the origin. The allowable value of the composite and foam design σa is measured by the test. According to the airworthiness clause, the safety factor of the composite material fs is 1.5, and the environmental factor of the composite material fe is 1.25 besides the safety factor. The shell element is used in the laminate structure and the foam. In model analysis, the primary performance metric is margin of safety υ, which is computed as

Table 1  Load on the gondola in load condition No.1
Load conditionFd/NLoad in the plane of propeller(Unilateral)
Fx/NFy/NFz/NMx1/(Nm)
1 50 078 -4 750 0 0 -1 112
Table 2  Load on the gondola in load condition No.2
Load conditionGt/NLanding gear load/N
xyz
2 32 732 20 370 25 463 0
Table 3  Load on the gondola in load condition No.3
Load conditionGt/NLanding gear load/N
xyz
3 32 732 0 41 932 23 063
υ= σaσmfsfe-1 (1)

where σm is the maximum calculated stress.

The calculation results of load condition No.1 are shown in Table 4, and the cloud diagram of the glass fiber tensile strain is shown in Fig.2. The maximum stress of the composite panel appears near the top skin of the frame, and the minimum margin of safety is 1.54. The maximum stress of foam appears on the boundary of frame web, and the minimum margin of safety is 5.91. Overall, the glass fiber and foam have greater residual strength under this condition.

Table 4  Calculation results of load condition No.1
ParameterMaximumMargin of safety
Tensile strain of glass fiber/με 1 825 1.54
Compression strain of glass fiber/με 1 088 2.53
Shear strain of glass fiber/με 1 476 2.52
Von mises stress of foam/MPa 0.11 5.91
Shear stress of foam/MPa 0.06 10.33
Overall displacement/mm 7.55

Fig.2  Cloud diagram of the glass fiber tensile strain under load condition No.1

The calculation results of load condition No.2 are shown in Table 5, and the cloud diagram of the glass fiber tensile strain is shown in Fig.3. The calculation results of condition No.3 are shown in Table 6, and the cloud diagram of the glass fiber tensile strain is shown in Fig.4. For load conditions No.2 and No.3, the maximum stress of composite panel both appears in the skin near the landing gear joint, and the minimum margin of safety for load condition No.2 is 0.01, while the minimum margin of safety for load condition No.3 is 0.04. The maximum stress of the foam both appears on the skin boundary near the landing gear diagonal strut joint, and the minimum margin of safety for load condition No.2 is 0.09, while the minimum margin of safety for load condition No.3 is 0.65. Compared with those of load condition No.2, the area of structure with higher stress and shear stress in load condition No.3 is larger. Under the two conditions, the margin of safety for the glass fiber and the foam are both small. Since the load calculation is conservative, the local element mesh is large.The structural safety will be verified through the limit load test.

Table 5  Calculation results of load condition No.2
ParameterMaximumMargin of safety
Tensile strain of glass fiber/με 4 593 0.01
Compression strain of glass fiber/με 2 914 0.32
Shear strain of glass fiber/με 3 513 0.48
Von mises stress of foam/MPa 0.70 0.09
Shear stress of foam/MPa 0.40 0.70
Overall displacement/mm 10.93

Fig.3  Cloud diagram of the glass fiber tensile strain under load condition No.2

Table 6  Calculation results of load condition No.3
ParameterMaximumMargin of safety
Tensile strain of glass fiber/με 3 967 0.17
Compression strain of glass fiber/με 3 680 0.04
Shear strain of glass fiber/με 4 884 0.06
Von mises stress of foam/MPa 0.46 0.65
Shear stress of foam/MPa 0.27 1.52
Overall displacement/mm 7.39

Fig.4  Cloud diagram of the glass fiber tensile strain under load condition No.3

3 Fabrication

3.1 Manufacturing of composite parts

In order to reduce the void content, the impregnation rate of prepreg resin is improved by optimizing the curing temperature curve to reduce the flow-induced void content. By optimizing the VBO layup of parts, the air entrapment in the curing process, and the gas-induced void content are reduced. Using small samples to analyze the void content of different processes, the curing temperature curve of parts is obtained, as shown in Fig.5. By adding dry fiberglass strands at the edge of the layer to improve the edge breathing of prepreg, the void content of parts can be effectively reduced and the quality of parts can be improved. The VBO layup of parts is shown in Fig.6.

Fig.5  Curing curve of prepreg

Fig.6  VBO layup schematic

In addition to optimizing the edge breathing of prepreg during curing, the following aspects should be paid attention to:

(1) When the prepreg is taken out from the cold storage, the packaging bag cannot be opened. It needs to be placed at room temperature for several hours until the prepreg is heated to room temperature.

(2) It is necessary to vacuum in the process of laying when there are many layers.

(3) As shown in Fig.7, the stepped edge with dry fiberglass strands can make the air flow between the layers faster.

Fig.7  Stepped edge with dry fiberglass strands

(4) Multiple vacuum valves need to be arranged for parts with large area.

(5) The thickness of the tool plate need to be uniform to ensure that the temperatures rise of different parts of prepreg plies rise uniformly.

(6) The air tightness of the mold is tested. The vacuum should be more than 9.2×104 Pa and the pressure drop should not exceed 2×103 Pa in 5 min.

Through the above measures, the void content of the parts can be effectively reduced to about 2% by micro-photograph image analysis. The void content of aerospace structures is acceptable at levels below 2%

11. Fig.8 shows the tool with lay-up and vacuum bag

Fig.8  Tool with lay-up and vacuum bag

3.2 Assembly

The gondola is assembled by assembly frame, and the assembly sequence is from bottom to top, from inside to outside. The order is the bottom skin, the frame, the floor beam, the floor, the side skin and the top plate. Most parts are located by face and pin holes on the assembly frame. After positioning, the parts are assembled by cementation or screw connection. When the cementation gap is greater than the design value, the composite gasket is added to reduce the gap. Each skin and frame is arranged with four pin holes for positioning, and three pin holes can be inserted smoothly during assembly, which shows that the manufacturing accuracy of parts is high.

4 Test

4.1 Test process

In order to verify the safety of gondola structure and the rationality of strength calculation method, the above three severe conditions were tested, and the test loads were set as the loads in Tables 1—3 multiplied by the safety factor of 1.5. Fig.9 shows the gondola test.

Fig.9  Actual gondola within the test fixture

The gondola was fixed and restrained with the longitudinal steel beam through the top joint. The landing gear load and the propeller load were loaded by the hydraulic actuator, and other loads were loaded by the counterweight. Several strain gauges were arranged on the outside of the gondola skin, the frame and the beam to monitor the stress of the structure. The test data were collected and stored in real time through the data acquisition box, and the actuator was loaded by the coordinated loading system. Data acquisition and actuator loading were carried out by the operator in the control room.

For each load condition, the pre-test of 40% limit load was carried out to eliminate the test gap. debug The test equipment was debugged, and unloaded to 0 after loading. Then, the structure was loaded step by step to 67% ultimate load for 30 s to observe whether there was harmful deformation. Then, the structure was loaded step by step to 100% ultimate load for 3 s to observe whether the structure was damaged and then unloaded to 0.

4.2 Test results and analysis

Three test conditions were loaded successfully, and no harmful deformation and damage were found, which indicated the safety of the gondola structure. The tensile, compressive and shear strain values of the composite measured by the strain gauge under load condition No.2 were compared with the predicted values of the finite element model, as shown in Figs.1012.The error statistics are shown in Table 7. Although the predicted compression strain values of the three strain gauges differ greatly from the test values, the other errors are less than 30%. The poor correlation of some data is due to the position error of the strain gauge, the strain gauge in the high strain gradient region,the stiffness error of the finite element model and statically indeterminate constraints.

Fig.10  Comparison of tensile strain under load condition No.2

Fig.11  Comparison of compression strain under load condition No.2

Fig.12  Comparison of shear strain under load condition No.2

Table 7  Error between simulation value and test value
Strain gaugenumberError/%
Tensile strainCompression strainShear strain
S1 11 8 10
S2 8 82 27
S3 13 15 10
S4 16 124 29
S5 7 12 1
S6 4 87 7
S7 9 14 6
S8 11 4 9

5 Cost Analysis

The gondola design always implements the requirements of low-cost design, and comprehensively considers the aspects of material selection, process, weight, mechanical properties and porosity.

(1) In the manufacturing process of composite parts, raw materials and labor account for a large majority of costs, with contributions from equipment, tooling, energy and consumables being comparatively small

41. Compared with carbon fiber prepreg and PMI foam, the cost of gondola materials for glass fiber prepreg and PVC foam can be reduced by about 50%. The quality inspection of glass fiber parts can be used visually, while the qualiy inspection of carbon fiber parts requires ultrasonic testing and porosity test plates. Although the resin infusion process using dry fiber and pure resin is better than VBO prepreg curing for economy and environment, the weight is unacceptable.So it is not used.

(2) The selection of VBO prepreg curing rather than autoclave curing is based on the following considerations. First, the cost of autoclave curing in equipment, mold and energy is higher than that of VBO prepreg curing

41. At the same time, due to the large length and size of the gondola skin, it is easier for VBO oven curing to form parts as a whole, thas the assembly frame is simplified and the expensive and time-consuming assembly is reduced42. As the gondola parts are made of foam sandwich structure, the VBO prepreg adopts low pressure technology, and the defective rate can be reduced by reducing the defects caused by autoclave, such as honeycomb core crushing and panel depression. Compared with autoclave curing process, VBO prepreg process has the same weight, slightly poor mechanical properties and porosity, but acceptable.

(3) VBO prepreg cure improves the autoclave cuing in several environmental performance metrics (greenhouse gas emissions, resource use, ecosystem quality and human health) by between 10% and 20% (as measured using each category’s appropriate unit), primarily through reductions in energy consumption

41. With the development trend of energy conservation, emission reduction and green aircraft, the research and application of VBO prepreg forming process is the direction of development in the future.

6 Conclusions

The AS700 civil manned airship gondola is designed and fabricated using low-cost composites and OoA processing. The cost of product development and batch production can be effectively reduced by selecting glass fiber prepreg, PVC foam and OoA processing. The composite parts are manufactured by the layer method, and they are only compacted and cured in the oven under vacuum pressure. The porosity of the parts can be reduced to about 2% by optimizing the edge breathing of the prepreg during the curing process, which meets the requirement of engineering application. During the assembly process, the positioning hole of the part fits well with the positioning pin of the mold frame, indicating that the part has high precision.

Three severe load conditions are selected to carry out the limit load test. The test shows that the gondola structure has no harmful deformation under 67% limit load and no damage under 100% limit load, which verifies the safety of the structure.

Considering the impact load of the landing gear, the reinforcing frame connected with the landing gear adopts metal materials. The metal frame and the composite skin adopt cementation and bolt connection, which brings about structural weight gain and cost increase. Further research is needed to ensure that the reinforcing frame adopt composite materials can meet the requirements of the whole life cycle.

This paper introduces the load, structure, strength, manufacturing process and test of the manned airship gondola, and demonstrates that it is feasible to choose low cost materials such as glass fiber and PVC foam, and use OoA processing to produce manned airship gondolas. The research results of this paper are consistent with the development prospect of low cost and green production of aircraft, and can provide certain references for the design of similar products.

Contributions Statement

Mr. ZHU Qiang designed the study,complied the gondola structure design,OoA processing research and experimental organization, and wrote the manuscript. Prof. TONG Mingbo contributed to the discussion and revision of the study. Mr. XIAO Peng contributed to the discussion and background of the study. Mr. LIU Chong contributed to the discussion and gondola fabrication. Mr. QIU Chen contributed to the gondola test. Ms. MA Jingjing contributed to the finite element analysis. Mr. JIN Tao contributed to the discussion. All authors commented on the manuscript draft and approved the submission.

Acknowledgements

This work was supported in part by China Special Vehicle Research Institute and the Priority Academic Program Development of Jiangsu Higher Education Institutions.

Conflict of Interest

The authors declare no competing interests.

References

1

ZHAO An’anYANG WenkaiYU Feiet al. RTM process for large-scale and high-performance composite components‍[J]. Journal of Nanjing University of Aeronautics & Astronautics2020521): 39-47. (in Chinese) [Baidu Scholar] 

2

YE CongjieGU XingjingYUAN Jianfenget al. Mechanical behavior of RTM composite cross joints‍[J].Journal of Nanjing University of Aeronautics & Astronautics2021533): 381387. (in Chinese) [Baidu Scholar] 

3

CHEN XZHANG XLI C Pet al. Uncertain modal analysis of unmanned aircraft composite landing gear‍[J]. Transactions of Nanjing University of Aeronautics and Astronautics2020375): 694701. [Baidu Scholar] 

4

SHI Z YDUAN N MLI Xet al. Analysis and control of surface delamination defects during milling of orthogonal aramid fiber-reinforced composites laminates‍[J]. Transactions of Nanjing University of Aeronautics and Astronautics2020373): 353359. [Baidu Scholar] 

5

NELE LCAGGIANO ATETI R. Autoclave cycle optimization for high performance composite parts manufacturing‍[J]. Procedia CIRP201657241-246. [Baidu Scholar] 

6

CENTEA TGRUNENFELDER L KNUTT S R. A review of out-of-autoclave prepregs‑Material properties, process phenomena, and manufacturing considerations‍[J]. Composites Part A—Applied Science and Manufacturing201570132-154. [Baidu Scholar] 

7

MEREDITH JBILSON EPOWE Ret al. A performance versus cost analysis of prepreg carbon fibre epoxy energy absorption structures‍[J]. Composite Structures2015124206-213. [Baidu Scholar] 

8

HYUN D KKIM DSHIN J Het al. Cure cycle modification for efficient vacuum bag only prepreg process‍[J]. Journal of Composite Materials2021558):1039-1051. [Baidu Scholar] 

9

HELMUS RCENTEA THUBERT Pet al. Out-of-autoclave prepreg consolidation: Coupled air evacuation and prepreg impregnation modeling‍[J]. Journal of Composite Materials20165010): 1403-1413. [Baidu Scholar] 

10

GRUNENFELDER L KNUTT S R. Void formation in composite prepregs—Effect of dissolved moisture‍[J]. Composites Science and Technology20107016): 2304-2309. [Baidu Scholar] 

11

SERRANO LOLIVIER PCINQUIN J. Compaction behavior of out-of-autoclave prepreg materials‍[C]//Proceedings of AIP Conference Proceedings. [S.l.]AIP Publishing LLC2017. [Baidu Scholar] 

12

LIU LZHANG B MWANG D Fet al. Effects of cure cycles on void content and mechanical properties of composite laminates‍[J]. Composite Structures2006733): 303-309. [Baidu Scholar] 

13

OLIVIER PCOTTU J PFERRET B. Effects of cure cycle pressure and voids on some mechanical properties of carbon-epoxy laminates‍[J]. Composites1995267): 509-515. [Baidu Scholar] 

14

KAY JFERNLUND G. Processing conditions and voids in out of autoclave prepregs‍[C]//Proceedings of the SAMPE 2012 Conference of the Society for the Advancement of Materials and Process Engineering. [S.l.]SAMPE20121-12. [Baidu Scholar] 

15

CENTEA THUBERT P. Out-of-autoclave prepreg consolidation under deficient pressure conditions‍[J]. Journal of Composite Materials20144816): 2033-2045. [Baidu Scholar] 

16

CENTEA THUBERT P. Measuring the impregnation of an out-of-autoclave prepreg by micro-CT‍[J]. Composites Science and Technology2011715):593-599. [Baidu Scholar] 

17

CENDER T ASIMACEK PADVANI S G. Gas permeability of partially saturated fabrics‍[C]//Proceedings of 2013 International Conference on Composite Materials. Montreal, Canada[s.n.]2013. [Baidu Scholar] 

18

SHIM S BSEFERIS J C. Thermal and air permeation properties of a carbon fiber toughened epoxy based prepreg system‍[J]. Journal of Applied Polymer Science1997651): 5-16. [Baidu Scholar] 

19

CENTEA THUBERT P. Modelling the effect of material properties and process parameters on tow impregnation in out-of-autoclave prepregs‍[J]. Composites Part A: Applied Science and Manufacturing2012439): 1505-1513. [Baidu Scholar] 

20

ARAFATH A R AFERNLUND GPOURSARTIP A. Gas transport in prepregs: Model and permeability experiments‍[C]//Proceedings of 2009 International Conference on Composite Materials. Edinburgh, U K[s.n.]2009. [Baidu Scholar] 

21

KAY JFAHRANG LHSIAO Ket al. Effect of process conditions on porosity in out-of-autoclave prepreg laminates‍[C]//Proceedings of ICCM-18 Conference. Jeju Island, Korea[s.n.]2011. [Baidu Scholar] 

22

FARHANG LFERNLUND G. Void evolution and gas transport during cure in out-of-autoclave prepreg laminates[C]//Proceedings of 2011 International SAMPE Technical Conference. [S.l.]SAMPE201123-26. [Baidu Scholar] 

23

GRUNENFELDER L KCENTEA THUBERT Pet al. Effect of room-temperature out-time on tow impregnation in an out-of-autoclave prepreg‍[J]. Composites Part A—Applied Science and Manufacturing201345119-126. [Baidu Scholar] 

24

LUCAS SHOWARD SSENGER J. Vacuum bag only processing: Improving prepreg out-time and porosity for large composite structure[C]//Proceedings of SAMPE 2010 Conf. Seattle, USASociety for the Advancement of Material and Process Engineering2010. [Baidu Scholar] 

25

NARESH KSALEM AKHAN K Aet al. Thermo‑mechanical compaction‑creep and void analysis of prepregs using XCT‑aided geometrical models‍[J]. Applied Composite Materials2021283):659-684. [Baidu Scholar] 

26

GRUNENFELDER L KFISHER CCABBLE Cet al. Defect control in out-of-autoclave manufacturing of structural elements‍[C]//Proceedings of the SAMPE 2012 Technical Conference. North Charleston, USA[s.n.]2012. [Baidu Scholar] 

27

YUAN ChaoCHENG WenliCHEN Jing. Research of out of autoclave composite porosity‍[J]. Fiber Reinforced Plastics/Composites20191289-93. (in Chinese) [Baidu Scholar] 

28

KIM DCENTEA TNUTT S R. Modelling and monitoring of out-time and moisture absorption effects on cure kinetics and viscosity for an out-of-autoclave (OoA) prepreg‍[J]. Composites Science and Technology2017138201-208. [Baidu Scholar] 

29

HSIAO KKAY JFERNLUND G. Gas transport and water evaporation in out-of-autoclave prepregs‍[C]//Proceedings of the 26th Annual Technical Conference of the American Society for Composites/the 2nd Joint US-Canada Conference on Composites.[S.l.]American Society for Composites2011. [Baidu Scholar] 

30

KAY JFERNLUND G. Processing conditions and voids in out of autoclave prepregs‍[C]//Proceedings of the SAMPE 2012 Conference of the Society for the Advancement of Materials and Process Engineering. [S.l.][s.n.]20121-12. [Baidu Scholar] 

31

ALPAY Y OUYGUR IKILINCEL M. On the optimum process parameters of infrared curing of carbon fiber-reinforced plastics‍[J]. Polymers and Polymer Composites2020286): 433-439. [Baidu Scholar] 

32

REPECKA LBOYD J. Vacuum-bag-only-curable prepregs that produce void-free parts‍[C]//Proceedings of the 47th International SAMPE Symposium and Exhibition. Long Beach, USASociety for the Advancement Material & Process Engneering20021862-1874. [Baidu Scholar] 

33

GRIMSLEY B WSUTTER J KBURKE E Ret al. Elevated temperature, residual compressive strength of impact-damaged sandwich structure manufactured out-of-autoclave:‍ NF1676L-13288[R].[S.l.]:[s.n.],2012. [Baidu Scholar] 

34

HARO ALEHMAN BYOSHIOKA Ket al. Rapid out-of-autoclave composite manufacturing for aerospace-grade prepregs‍[J]. SAMPE Journal2015512): 7-14. [Baidu Scholar] 

35

JIN B CLI XMIER Ret al. Parametric modeling, higher order FEA and experimental investigation of hat-stiffened composite panels‍[J]. Composite Structures2015128207-220. [Baidu Scholar] 

36

LANE S AHIGGINS JBISKNER Aet al. Out-of-autoclave composite fairing design, fabrication, and test‍[J]. Journal of Manufacturing Science and Engineering20111333): 031020. [Baidu Scholar] 

37

BERNETICH K R. Evaluation of detail part fabrication using out-of-autoclave prepreg‍[C]//Proceedings of the 54th International SAMPE Symposium and Exhibition. [S.l.][s.n.]201017-20. [Baidu Scholar] 

38

BOND G GHAHN G LJOST K Met al. Prepreg non-autoclave manufacturing technology‑program overview and co-cure enablers for disruptive, pervasive use‍[J]. SAMPE Journal2012485): 8-15. [Baidu Scholar] 

39

RUSSELL J DSHENK BHOLZWARTH Ret al. Advanced composite cargo aircraft‍[C]//Proceedings of the 41st International SAMPE Technical Conference. Witchita, USASociety for the Advancement of Material and Process Engineering2009. [Baidu Scholar] 

40

SOLTANI S AVALI HBHASIN Aet al. Effect of nonwoven fabric type and stacking sequence on distortion of flat panels made of out-of-autoclave carbon-fiber epoxy prepreg‍[C]//Proceedings of the 2014 Technical Conference of the Society for the Advancement of Materials and Process Engineering (SAMPE Tech 2014). La Jolla, USADestech Publications2014. [Baidu Scholar] 

41

WITIK R AGAILLE FTEUSCHER Ret al. Economic and environmental assessment of alternative production methods for composite aircraft components‍[J]. Journal of Cleaner Production20122991102. [Baidu Scholar] 

42

BOYD JMASKELL R K. Product design for low cost manufacturing of composites for aerospace applications‍[C]//Proceedings of the 46th International SAMPE Symposium and Exhibition: A Materials and Processes Odyssey. [S.l.][s.n.]2001898-907. [Baidu Scholar] 

WeChat

Mobile website