阅读说明：本技术 一种显示复合材料低速冲击损伤的紫外荧光示踪层 (ultraviolet fluorescent tracing layer for displaying low-speed impact damage of composite material ) 是由 王迎芬 潘翠红 周洪飞 孙占红 于 2019-08-02 设计创作，主要内容包括：本发明是一种显示复合材料低速冲击损伤的紫外荧光示踪层,该方法为在复合材料本体近表层铺覆一层或多层紫外荧光树脂预浸料,在紫外荧光树脂预浸料外表面铺覆遮挡层,与其他树脂基复合材料一同固化成型制成树脂基复合材料制件,功能是通过该紫外荧光预浸料复合材料层受到低速冲击后的状态变化,来辨别复合材料相应冲击受损区域、冲击能量的大小及冲击后剩余压缩强度；本发明能够在遭受低速冲击、造成内部损伤时,在表面能及时显示出内部的损伤情况,使地面保障人员可及时发现潜在危险,保障飞行器安全。(The invention relates to an ultraviolet fluorescent tracing layer for displaying low-speed impact damage of a composite material, which is characterized in that one or more layers of ultraviolet fluorescent resin prepreg are paved on the near surface layer of a composite material body, a shielding layer is paved on the outer surface of the ultraviolet fluorescent resin prepreg, and the ultraviolet fluorescent resin prepreg and other resin-based composite materials are cured and molded together to prepare a resin-based composite material part; the invention can display the internal damage condition on the surface in time when suffering from low-speed impact and causing internal damage, so that ground support personnel can find potential danger in time and the safety of the aircraft is guaranteed.)

1. An ultraviolet fluorescent tracer layer for displaying low-speed impact damage of a composite material, which is characterized in that: the tracing layer (2) is a resin prepreg which is paved on the near surface layer of the composite material body (1) and has an ultraviolet fluorescence reflection function, the shielding layer (3) is paved on the surface of the tracing layer (2), and the tracing layer (2) and the composite material body (1) are cured and molded together with the resin matrix composite material.

2. The ultraviolet fluorescent tracer layer for indicating low-speed impact damage of composite material according to claim 1, wherein: the tracing layer (2) and the composite material body (1) adopt the same resin matrix and reinforced fibers, and ultraviolet fluorescent powder is added when the resin matrix of the tracing layer (2) is prepared.

3. The ultraviolet fluorescent tracer layer for indicating low-speed impact damage of composite material according to claim 1, wherein: the resin matrix of the resin prepreg of the tracer layer (2) is epoxy resin, bismaleimide resin, phenolic resin or polyimide resin.

4. The ultraviolet fluorescent tracer layer for indicating low-speed impact damage of composite material according to claim 2, wherein: the reinforcement of the resin prepreg of the tracing layer (2) is carbon fiber, glass fiber, aramid fiber or natural plant fiber; the reinforcing fibers are in the form of unidirectional fibers, laid fabrics, plain weave, satin weave or twill weave.

5. The ultraviolet fluorescent tracer layer for indicating low-speed impact damage of composite material according to claim 1, wherein: the tracing layer (2) is laid with 1-10 layers.

6. The ultraviolet fluorescent tracer layer for indicating low-speed impact damage of composite material according to claim 1, wherein: the shielding layer (3) and the composite material body (1) adopt the same resin matrix and the same reinforced fibers.

7. The ultraviolet fluorescent tracer layer for indicating low-speed impact damage of composite material according to claim 1, wherein: the shielding layer (3) is made of resin film with the same resin matrix as the composite material body (1).

8. The ultraviolet fluorescent tracer layer for indicating low-speed impact damage of composite material according to claim 1, wherein: the shielding layer (3) is made of aircraft paint.

9. The ultraviolet fluorescent tracer layer for indicating low-speed impact damage of composite material according to claim 1, wherein: the curing and forming method comprises autoclave forming, vacuum bag forming and compression molding.

Technical Field

The invention discloses an ultraviolet fluorescent tracing layer for displaying low-speed impact damage of a composite material, and belongs to the technical field of composite material manufacturing.

background

The composite material has excellent performances of high specific strength, high specific stiffness, corrosion resistance, fatigue resistance and the like, and is widely applied to the field of aerospace, and the using amount of the composite material becomes a mark for measuring the structural advancement of an aircraft. However, composite materials are very sensitive to out-of-plane low-speed impacts, and when a composite laminate is subjected to a high-energy out-of-plane low-speed impact (low-speed impact generally refers to an impact event processed in a quasi-static manner, the upper limit of impact speed is tens of meters/second, and the impact speed depends on the rigidity of a target, material characteristics and the quality and rigidity of an impact object. At the moment, the compression strength after impact can be reduced by 60 percent at most, and the safety of the airplane is seriously threatened. The durability and damage tolerance performance of composite out-of-plane low speed impacts has therefore been one of the major concerns of research.

There are 2 approaches to solve the problem of low-speed impact outside the composite material surface. Firstly, a composite material system with high damage tolerance performance is researched and developed, pits/cracks on the surface of a lower-layer plate are more obviously visible under the same out-of-plane low-speed impact energy, and the compression performance after impact is improved as much as possible; secondly, the impact position of the laminate is positioned by adopting monitoring means, auxiliary materials and the like, and then detailed nondestructive testing is carried out aiming at the position. The monitoring means comprises a strain gauge, a grating optical fiber, a piezoelectric plate and the like, and the auxiliary material comprises surface layer ceramic (patent number CN102990990A), surface layer (publication number CN101503014A) and the like. By adopting monitoring means such as strain gauges, grating optical fibers and piezoelectric patches, a large number of sensors and wires need to be arranged on the airplane structure, whether the structure is damaged or not is monitored in real time, the system is complex, and the weight of the airplane structure is increased. In addition, the bonding strength of the strain gauge and the like is obviously influenced by the environment, and the reliability is not high. The adoption of auxiliary materials such as surface ceramics, surface high-toughness paving layers and the like can cause the problems of mismatched thermal expansion coefficients with the paving layers of the member body, incompatibility of two-phase matrixes and the like, and easily cause the problems of thermal deformation and the like of the member, and the preparation process is relatively complex and has low reliability.

Disclosure of Invention

The invention provides an ultraviolet fluorescent tracing layer for displaying low-speed impact damage of a composite material, aiming at the defects of the prior art, wherein one or more layers of ultraviolet fluorescent resin prepreg are paved on the near surface layer of a target composite material body, a shielding layer is paved on the outer surface of the ultraviolet fluorescent resin prepreg, and the ultraviolet fluorescent resin prepreg and other resin-based composite materials are cured and molded together to prepare a resin-based composite material part.

The purpose of the invention is realized by the following technical scheme:

The ultraviolet fluorescent tracing layer for displaying the low-speed impact damage of the composite material is characterized in that: the tracing layer 2 is a resin prepreg which is paved on the near surface layer of the composite material body 1 and has an ultraviolet fluorescence reflection function, the shielding layer 3 is paved on the surface of the tracing layer 2, and the tracing layer 2 and the composite material body 1 are cured and molded together with a resin matrix composite material workpiece.

Further, the tracer layer 2 and the composite material body 1 adopt the same resin matrix and reinforcing fibers, and ultraviolet fluorescent powder is added when the resin matrix of the tracer layer 2 is prepared. The reinforcement of the resin prepreg of the tracer layer 2 is carbon fiber, glass fiber, aramid fiber or natural plant fiber; the reinforcing fibers are in the form of unidirectional fibers, laid fabrics, plain weave, satin weave or twill weave.

Further, the resin matrix of the resin prepreg of the trace layer 2 is epoxy resin, bismaleimide resin, phenol resin, or polyimide resin.

Further, the shielding layer 3 and the composite material body 1 adopt the same resin matrix and reinforcing fibers. Or the shielding layer 3 is made of resin film with the same resin matrix as the composite material body 1.

Further, the shielding layer 3 is made of aircraft paint.

The curing and forming method comprises autoclave forming, vacuum bag forming and compression molding.

when the resin matrix composite body 1 is impacted by the impact head 4 at a low speed, the shielding layer 3 on the back of the resin matrix composite body 1 can crack, and the inside of the resin matrix composite body 1 can crack and break fibers, and the like, and at the moment, the ultraviolet lamp is used for irradiating the back of the resin matrix composite body 1, so that the region of impact damage can be displayed by quickly finding out light rays transmitted from the shielding layer 3, and the impact damage can be quickly reinforced or repaired, and the requirement of visual detection is met.

the technical scheme of the invention has the following advantages:

1. The invention provides an ultraviolet fluorescent tracing layer for displaying low-speed impact of a composite material, which is a prepreg added with a proper amount of ultraviolet fluorescent powder, when the tracing layer is applied to a resin-based composite material workpiece, when the composite material workpiece is subjected to out-of-plane impact, a shielding layer falls off or cracks are generated, so that the ultraviolet fluorescent tracing layer is exposed and can be visually detected under the irradiation of an ultraviolet lamp, and further, the corresponding impact damaged area, the impact energy and the residual compression strength after impact of the composite material are distinguished;

2. The ultraviolet fluorescent tracing layer displays the impact position and severity on the surface in time when the resin-based composite material workpiece is subjected to out-of-plane low-speed impact to cause invisible internal damage, so that ground maintenance and guarantee personnel can discover potential danger in time to ensure the safety of an aircraft. The ultraviolet fluorescent tracer layer is applied to specific areas (such as airfoil skin, fuselage skin and the like) of an aircraft, wherein the areas are areas which can be accessed by ground maintainers through a wallboard access hole and can be found by irradiating the back surface of the airfoil skin with an ultraviolet lamp; or when the ground maintenance personnel routinely check and maintain, the internal decoration of the machine body is removed, and the impact damage area can be found from the inner side by utilizing ultraviolet rays and the like, so that the detectability of out-of-plane low-speed impact is improved, the design allowable value of the composite material can be improved, and the structure weight reduction is favorably realized;

3. The ultraviolet fluorescent tracing layer only covers one or more layers on the surface of the composite material body, so that the basic performance of the original composite material is basically maintained, the influence on the existing material and process is avoided, and the potential of the existing material is fully exploited. The ultraviolet fluorescent tracing layer is suitable for composite materials of various systems and various forming processes (autoclave, vacuum bag, mould pressing and the like), and has wide application range.

drawings

FIG. 1 is a schematic diagram of the position and structure of the UV fluorescent tracer layer in a composite material part.

Detailed Description