Search

CN-121973468-A - Lightweight automobile bumper based on long fiber reinforced composite material and preparation process thereof

CN121973468ACN 121973468 ACN121973468 ACN 121973468ACN-121973468-A

Abstract

The invention discloses a lightweight automobile bumper based on a long fiber reinforced composite material and a preparation process thereof, comprising the steps of mixing energy absorbing fluid with a mesoporous carrier, vacuum impregnating, and sucking the energy absorbing fluid into the mesoporous carrier to prepare free liquid filler; the continuous fibers are immersed in the resin, directionally paved in a hot-pressing die of the automobile bumper, long fibers are added to fill and mix with thermoplastic polymer matrix of the filler, a plasticizing agent of supercritical fluid is injected into the molten polymer matrix in a die cavity under the condition of pressurizing and heating, free volume is increased by the penetration of the plasticizing agent among polymer molecular chains, the continuous fibers, the long fibers and the filler are immersed in the matrix and rolled and maintained in the low-temperature environment, the pressure is released, the die is removed, the light bumper is obtained by cooling and shaping, and the mechanical integrity of the anti-collision structure under the extremely high-speed collision working condition is further ensured.

Inventors

  • YUAN TAO
  • ZHANG YAN

Assignees

  • 江苏科新汽车装饰件有限公司

Dates

Publication Date
20260505
Application Date
20260330

Claims (10)

  1. 1. The preparation process of the lightweight automobile bumper based on the long fiber reinforced composite material is characterized by comprising the following steps of: S1, mixing energy absorbing fluid with a mesoporous carrier, and vacuum impregnating, and sucking the energy absorbing fluid into the mesoporous carrier to prepare free liquid filler; s2, impregnating continuous fibers into resin, directionally paving the continuous fibers into a hot-pressing die of an automobile bumper, and respectively adding long fibers, filler and polymer matrix for filling; s3, melting the S2 product in a pressurized and heated environment, injecting a plasticizing agent of a supercritical fluid, penetrating the plasticizing agent into polymer molecular chains to increase free volume, and carrying out infiltration, calendaring and pressure maintaining in a low-temperature environment; and S4, releasing pressure and demolding, inducing a foaming structure in situ in the polymer matrix and at the joint interface of the polymer matrix, the fiber and the filler, and cooling and shaping to obtain the lightweight bumper.
  2. 2. The process for preparing a lightweight automobile bumper based on a long fiber reinforced composite material according to claim 1, wherein in the step S2, the polymer matrix is selected from a blend of any one or more of polyamide 6, polyamide 66, polypropylene, or polyethylene terephthalate; The continuous fiber is selected from any one of continuous carbon fiber, continuous aramid fiber or continuous ultra-high molecular weight polyethylene fiber; the long fiber is selected from any one of long basalt fiber, long glass fiber or long plant natural fiber.
  3. 3. The preparation process of the light-weight automobile bumper based on the long fiber reinforced composite material, which is characterized in that in the step S1, the energy absorbing fluid is any one of shear thickening fluid, magnetorheological fluid or electrorheological fluid based on nano silicon dioxide/polyethylene glycol mixture; The mesoporous carrier is any one of a mesoporous silica nanotube, a carbon nanotube or a halloysite nanotube; the mass ratio of the energy absorbing fluid to the mesoporous carrier is 1:2 to 1.5:1.
  4. 4. The process for preparing the lightweight automobile bumper based on the long fiber reinforced composite material according to claim 1, wherein in the step S3, the plasticizer is any one of supercritical carbon dioxide or supercritical nitrogen.
  5. 5. The process for preparing a lightweight automobile bumper based on a long fiber reinforced composite material according to claim 1, wherein in the S2, the mass ratio of continuous fibers to the long fibers is 0.8:1-1.5:1; the mass fraction of the filler added into the whole composite material of the bumper is 3.5% -4.5%.
  6. 6. The process for preparing the lightweight automobile bumper based on the long fiber reinforced composite material according to claim 1, wherein in the step S1, the vacuum degree of vacuum impregnation is controlled to be-0.08 to-0.1 MPa, and the impregnation time is 2-6 hours; In the step S2, long fiber thermoplastic particles with the length of the long fiber of 10-15mm or a thermal state sheet is added; The directional laying is to lay the prepreg part of the continuous fiber in multiple layers in orthorhombic or unidirectional directions strictly along the stress distribution direction of forward collision in the main anti-collision beam area and the corner crumple area of the bumper.
  7. 7. The process for preparing the lightweight automobile bumper based on the long fiber reinforced composite material according to claim 1, wherein in the step S3, the injection pressure of the supercritical fluid is controlled to be 8MPa-20MPa at 180-200 ℃ in a low-temperature environment, and the soaking and calendaring dwell time is 10-30 minutes.
  8. 8. The preparation process of the lightweight automobile bumper based on the long fiber reinforced composite material, which is characterized in that in the step S4, the pressure release rate of pressure release is 50MPa/S-150MPa/S, and the pore diameter of the foaming structure induced in situ is controlled to be 10-15 μm.
  9. 9. A lightweight automotive bumper based on long fiber reinforced composite material, based on the manufacturing process of any one of claims 1-8, comprising: a thermoplastic polymer matrix of a continuous phase; continuous fibers and long fibers embedded in the polymer matrix; a filler dispersed within the polymer matrix and at the fiber interface; And the foam structure is distributed at the three-phase combination interface of the polymer matrix, the fiber and the filler, wherein air holes are formed in the foam structure, and the continuous fiber, the long fiber and the mesoporous carrier in the filler form a three-dimensional physical lap joint support network together with the air holes.
  10. 10. The lightweight automobile bumper based on long fiber reinforced composite material according to claim 9, wherein the filler and the air holes form a periodic microstructure of phonon crystal forbidden band effect at the material internal interface; when being impacted at high speed and generating high-frequency extremely high shearing force higher than a preset threshold value, the periodic microstructure blocks and localizes high-frequency destructive stress waves, and meanwhile energy-absorbing fluid in the filler core is instantaneously stimulated to generate hydrodynamic clustering solidification, so that kinetic energy is converted into heat energy to be dissipated in a gradient mode.

Description

Lightweight automobile bumper based on long fiber reinforced composite material and preparation process thereof Technical Field The invention relates to the field of automobile bumper preparation, in particular to a lightweight automobile bumper based on a long fiber reinforced composite material and a preparation process thereof. Background With the continuous improvement of the requirements of light weight and safety performance of automobiles, the traditional metal bumpers are gradually replaced by various composite materials. The long fiber reinforced composite material has excellent specific strength, specific modulus and good impact resistance, and has obvious application potential in the field of automobile structural parts. Such materials are typically injection molded or compression molded, wherein fibers having lengths ranging from several millimeters to tens of millimeters are combined with a thermoplastic or thermosetting resin matrix to produce a highly integrated component that provides an effective path for lightweight bumper design. In the prior art, in order to further optimize comprehensive performance and cost, a composite material scheme of adopting various fibers or different forms of fibers for hybrid reinforcement is paid attention to, however, when the hybrid fiber composite material is used for dealing with high-speed impact working conditions, an internal multiphase heterogeneous interface of the hybrid fiber composite material often becomes a weak link of mechanical properties, and as the interface bonding strength, the thermal expansion coefficient and the modulus between different fibers and a resin matrix are different, stress waves are easy to generate strong reflection and refraction at a phase boundary under the instant action of high-speed load, obvious stress concentration is caused, the interface layer is often caused to generate microcrack and debonding at the beginning of dynamic load, and is rapidly expanded into macroscopic interlayer tearing and stripping failure, the structural integrity is seriously weakened, the energy absorption efficiency of the material is rapidly reduced, and the strict requirements of a stable and progressive crushing energy absorption of an automobile bumper in high-speed collision are difficult to meet. Disclosure of Invention The invention overcomes the defects of the prior art and provides a light-weight automobile bumper based on a long fiber reinforced composite material and a preparation process thereof. In order to achieve the aim, the technical scheme adopted by the invention is that the preparation process of the lightweight automobile bumper based on the long fiber reinforced composite material comprises the following steps of: S1, mixing energy absorbing fluid with a mesoporous carrier, and vacuum impregnating, and sucking the energy absorbing fluid into the mesoporous carrier to prepare free liquid filler; S2, impregnating continuous fibers into resin, directionally paving the continuous fibers into a hot-pressing die of an automobile bumper, and adding long fibers to fill and mix with a thermoplastic polymer matrix of filler; s3, injecting a plasticizing agent of a supercritical fluid into a molten polymer matrix in a die cavity under a pressurized and heated environment, penetrating the plasticizing agent into polymer molecular chains to increase free volume, and carrying out infiltration and calendaring pressure maintaining on continuous fibers, long fibers and fillers by the matrix under a low-temperature environment; and S4, releasing pressure and demolding, inducing a foaming structure in situ in the polymer matrix and at the joint interface of the polymer matrix, the fiber and the filler, and cooling and shaping to obtain the lightweight bumper. In a preferred embodiment of the present invention, in S2, the polymer matrix is selected from a blend of any one or more of polyamide 6, polyamide 66, polypropylene, or polyethylene terephthalate; The continuous fiber is selected from any one of continuous carbon fiber, continuous aramid fiber or continuous ultra-high molecular weight polyethylene fiber; the long fiber is selected from any one of long basalt fiber, long glass fiber or long plant natural fiber. In a preferred embodiment of the present invention, in S1, the energy absorbing fluid is selected from any one of a shear thickening fluid, a magnetorheological fluid, or an electrorheological fluid based on a nano silica/polyethylene glycol mixture; The mesoporous carrier is any one of a mesoporous silica nanotube, a carbon nanotube or a halloysite nanotube; the mass ratio of the energy absorbing fluid to the mesoporous carrier is 1:2 to 1.5:1. In a preferred embodiment of the present invention, in S3, the plasticizer is selected from any one of supercritical carbon dioxide or supercritical nitrogen. In a preferred embodiment of the present invention, in S2, the mass ratio of continuous fibers to long fibers is 0.8:1 to 1.5