Fig.1

Schematic diagram of variable thickness composite material structure［17］

Fig.2

Flow chart of global and local collaborative interaction ply design and verification methods

Table 1

Strength performance parameters of prepreg with lightning protection function

Fig.3

Schematic diagram of structure of typical aircraft auxiliary fuel tank

Fig.4

Load amplitude curves under impact conditions

Fig.5

Comparison of experimental and simulated load-displacement curves

Table 2

Modulus parameters of prepreg with lightning protection function

Table 3

Load situation of auxiliary fuel tank under different loading conditions

Fig.6

Zoning of the overall structure of the auxiliary fuel tank

Table 4

Skin ply sequence information of auxiliary fuel tank

Table 5

Reinforcement ply sequence information of auxiliary fuel tank

Fig.7

Maximum stress of skin with different sizes of skin mesh

Fig.8

Comparison of maximum microstrain of skin and maximum microstrain of ribs with different ply schemes and loading

Fig.9

Optimization results of skin ply sequence for auxiliary fuel tank

Fig.10

Modeling of shell-to-solid submodel

Fig.11

Finite element model of specimen with variable thickness

Fig.12

Different intercalation methods of composite materials

Fig.13

Structural dimension diagram of specimens with variable thickness

Fig.14

Loading method for specimens with variable thickness

Table 6

Bending performance of specimens with three different intercalation methods

Fig.15

Bending strength and load-displacement curves of specimens with different intercalation methods

Fig.16

Bending loading process of specimens with variable thickness

Fig.17

Comparison of load-displacement curves obtained by forward bending test and by finite element method

Fig.18

Failure evolution process of specimens with variable thickness

Fig.20

Sub-model of variable-thickness cross-section for auxiliary fuel tank

Fig.21

Stress distribution cloud map of sub-model

Fig. 22

Global ply information of the skin of the auxiliary fuel tank

Fig.23

Strain variation curves of reinforcement bars at different angles before and after optimization

Table 7

Natural frequencies of each order before and after optimization of the auxiliary fuel tank

Fig.24

Micro strain response of skin under sawtooth wave conditions at the back peak before and after optimization

Fig.25

Variation curve of maximum microstrain under ejection and interception impacts before and after optimization

Fig.26

Time dependent curves of skin stress under ejection and interception impacts before and after optimization

Fig.27

Static test of auxiliary fuel tank of composite material