Commercial vehicle composite protective cross beam and forming method thereof

Abstract

The invention provides a composite protective cross beam for a commercial vehicle. The composite protective cross beam for the commercial vehicle is made of a composite material formed by thermosetting resin and a fiber reinforced material. Wherein the thermosetting resin comprises a bisphenol A type epoxy resin material, and the fiber reinforced material comprises a unidirectional continuous glass fiber layer and a triaxial glass fiber fabric layer. Compared with a protective cross beam made of metal, the protective cross beam made of the composite material formed by the thermosetting resin and the fiber reinforced material is lighter in mass, higher in strength, better in toughness and better in corrosion resistance and fatigue resistance. In addition, the invention further provides a forming method of the commercial vehicle composite protection cross beam.

Description

Technical Field

[0001] The invention relates to the technical field of automobile parts, and in particular to a composite protective beam for a commercial vehicle and a forming method thereof. Background Art

[0002] As a safety regulation part of automobiles, automobile protective beams are used to absorb and disperse the impact force to protect the safety of passengers when the vehicle collides. Due to the high strength requirements, they are currently mainly made of metal materials. However, metal protective beams have the problems of heavy parts and corrosion and rust after long-term use. In addition, metal protective beams are very rigid and are very likely to cause damage to vehicles and personnel when a collision occurs. Summary of the invention

[0003] In view of the defects existing in the prior art, the technical problem solved by the present invention is: to provide a composite protective beam for commercial vehicles and a forming method thereof, which can solve the problems in the prior art that the metal protective beam is heavy, easy to corrode and rust, and has poor impact toughness.

[0004] To achieve the above objectives, in a first aspect, the present invention provides a composite protective beam for a commercial vehicle, which is made of a composite material including a thermosetting resin and a fiber-reinforced material; wherein the thermosetting resin includes a bisphenol A epoxy resin material, and the fiber-reinforced material includes a unidirectional continuous glass fiber layer and a triaxial glass fiber fabric layer.

[0005] Preferably, in parts by weight, the bisphenol A epoxy resin material includes 100 parts of epoxy resin, 80-90 parts of curing agent, 20-30 parts of composite toughening agent, 2-3 parts of accelerator, 2-3 parts of antioxidant, 0.5-2 parts of internal release agent, and 1-2 parts of color paste.

[0006] Preferably, the composite toughening agent includes a polyhydroxyl functional linear polyether compound and a nano core-shell toughened epoxy resin.

[0007] Preferably, the mass ratio of the polyhydroxyl functional linear polyether compound to the nano core-shell toughened epoxy resin is 1:(0.5-1.5).

[0008] Preferably, the fiber-reinforced material is formed by alternately stacking unidirectional continuous glass fiber layers and tri-axial glass fiber fabric layers.

[0009] Preferably, the cross-section of the composite protective beam of the commercial vehicle is an asymmetric hollow structure about the neutral axis.

[0010] Preferably, the commercial vehicle composite protective cross beam is provided with a reinforcing sheet on the inner wall of the hollow structure.

[0011] Preferably, the reinforcing sheet is a prepreg comprising epoxy resin and glass fiber fabric.

[0012] Preferably, the reinforcing sheet is bonded to the inner wall via an expansion core mold.

[0013] In a second aspect, the present invention further provides a method for forming the composite protective beam for a commercial vehicle as described above, comprising the following steps:

[0014] Preparing a thermosetting resin adhesive solution, and immersing the fiber-reinforced material in the thermosetting resin adhesive solution;

[0015] In the molding die, the thermosetting resin glue impregnated with the fiber reinforcement material is heated and cured to obtain the commercial vehicle composite protective beam.

[0016] Compared with the prior art, the advantages of the present invention are:

[0017] (1) Compared with metal protective beams, the protective beams made of composite materials formed by the above-mentioned thermosetting resin and fiber-reinforced materials are lighter, stronger, more ductile, and more corrosion-resistant and fatigue-resistant;

[0018] (2) Compared with the conventional symmetrical structure in the art, the cross section of the composite protective beam of a commercial vehicle is designed to be an asymmetric hollow structure with a neutral axis, making full use of the performance difference of the material under different stress states, with stronger load-bearing stability and better lightweight effect;

[0019] (3) The present invention arranges a reinforcing sheet on the inner wall of the hollow structure, which has higher strength and better lightweight effect compared with the prior art in which the interior is filled with foaming material and honeycomb material to enhance the structural stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 This is a schematic cross-sectional view of a composite protective beam for a commercial vehicle in Example 1 of the present invention;

[0022] Figure 2 This is a schematic cross-sectional view of a composite protective beam for a commercial vehicle in Example 3 of the present invention;

[0023] Figure 3 This is a front view of a composite protective beam for commercial vehicles according to an embodiment of the present invention.

[0024] In the figure: 1-composite protective beam; 2-reinforcement rib; 3-reinforcement plate; 4-outer ventral plate; 5-inner ventral plate; 6-end of composite protective beam; 7-bracket; 8-stress concentration point. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The embodiment of the present invention provides a composite protective beam for commercial vehicles and a preparation method thereof. The composite protective beam for commercial vehicles is made of a composite material including a thermosetting resin and a fiber-reinforced material, which greatly reduces the mass of the protective beam, is not easily corroded or rusted, and has strong impact toughness, thereby solving the problem in the prior art that the metal protective beam is heavy, easily corroded or rusted, and has poor impact toughness.

[0027] In order to achieve the above technical effects, the overall idea of ​​the present invention is as follows:

[0028] On the one hand, the present invention provides a composite protective beam for a commercial vehicle, which is made of a composite material including a thermosetting resin and a fiber-reinforced material; wherein the thermosetting resin includes a bisphenol A epoxy resin material, and the fiber-reinforced material includes a unidirectional continuous glass fiber layer and a tri-axial glass fiber fabric layer.

[0029] Compared with protective beams made of metal, protective beams made of the composite material formed by the above-mentioned thermosetting resin and fiber-reinforced material have lighter weight, higher strength, better toughness, and better corrosion resistance and fatigue resistance.

[0030] Preferably, in parts by weight, the bisphenol A epoxy resin material includes 100 parts of epoxy resin, 80-90 parts of curing agent, 20-30 parts of composite toughening agent, 2-3 parts of accelerator, 2-3 parts of antioxidant, 0.5-2 parts of internal release agent, and 1-2 parts of color paste.

[0031] Preferably, the composite toughening agent comprises a polyhydroxyl functional linear polyether compound and a nano core-shell toughened epoxy resin. The mass ratio of the polyhydroxyl functional linear polyether compound to the nano core-shell toughened epoxy resin is 1:(0.5-1.5). The rotational viscosity of the polyhydroxyl functional linear polyether compound at 23°C is 50cp-80cp, the viscosity of the nano core-shell toughened epoxy resin is 4000cp-5500cp, and the CSR content of the core-shell rubber particles is 25%.

[0032] Specifically, the polyhydroxyl functional linear polyether compound is the polyhydroxyl functional linear polyether compound 410; the nano core-shell toughened epoxy resin is the nano core-shell toughened epoxy resin EMX1205 or the nano core-shell toughened epoxy resin EPX225.

[0033] The polyhydroxyl functional linear polyether compound and nano core-shell toughened epoxy resin in the composite toughening agent in this embodiment can give full play to the respective advantages of the two substances and produce a synergistic effect. The polyhydroxyl functional linear polyether compound can increase the proportion of flexible network in the cross-linked structure of the body through the reaction with the epoxy resin and the curing agent, and improve the flexibility of the cured product. The nano core-shell toughened epoxy resin plays a role in absorbing impact energy through a special core-shell structure, thereby improving the fatigue strength and heat resistance of the beam. In addition, the good compatibility of the polyhydroxyl functional linear polyether compound also helps to improve the problem of uneven dispersion of the core-shell toughening agent in the epoxy resin and affecting the stability of the material.

[0034] Preferably, the curing agent is selected from one or more of methyltetrahydropropionic anhydride, methylhexahydropropionic anhydride, and dodecenylsuccinic anhydride.

[0035] Preferably, the promoter is selected from one or more of triethylamine and 2-ethyl-4-methylimidazole.

[0036] Preferably, the internal mold release agent is a mixed solution comprising a high molecular weight fatty alcohol and a fatty salt. Specifically, the internal mold release agent of this embodiment can be selected from XY-HG172 mold release agent.

[0037] Preferably, the antioxidant is selected from one or more of hydroquinone, methylhydroquinone, benzodiquinone, 1,4-naphthoquinone and anthraquinone.

[0038] Preferably, the fiber-reinforced material is formed by alternating unidirectional continuous glass fiber layers and triaxial glass fiber fabric layers. The fiber-reinforced material of the above structure has good interlayer performance and longitudinal and transverse strength, and solves the problem of vibration fatigue cracking of unidirectional continuous glass fiber beams. The fiber content in the fiber-reinforced material is 65% to 75%.

[0039] Preferably, the ply structure of the fiber-reinforced material of the present embodiment is: +45° / -45° / 90° tri-axial glass fiber fabric layer, 0° continuous glass fiber layer, +45° / -45° / 90° tri-axial glass fiber fabric layer, 0° continuous glass fiber layer, +45° / -45° / 90° tri-axial glass fiber fabric layer. The present embodiment arranges the fiber-reinforced material into the above-mentioned five-layer structure, which can improve the uniformity of the distribution of glass fibers in all directions, thereby improving the strength of the overall structure.

[0040] Preferably, in the entire fiber-reinforced material, the proportions of 0° glass fiber, 45° glass fiber, -45° glass fiber, and 90° glass fiber are 40%-55%, 15%-20%, 15%-20%, and 15%-20%, respectively. In the embodiment of the present invention, the content of 0° glass fiber in the fiber-reinforced material is set relatively large to ensure the longitudinal strength of the protective beam. At the same time, 15%-20% of 45° glass fiber, 15%-20% of -45° glass fiber, and 15%-20% of 90° glass fiber are used to prevent the 0° continuous glass fiber from anti-vibration fatigue cracking, thereby improving the lateral strength of the protective beam.

[0041] Preferably, the cross-section of the composite protective beam of the commercial vehicle is an asymmetric hollow structure about the neutral axis.

[0042] When the protective beam is subjected to bending stress, the inner web is subjected to tensile stress, the outer web is subjected to compressive stress, and the middle part is mainly subjected to shear force. Experiments have shown that the tensile strength of the composite material formed by thermosetting resin and fiber-reinforced material used in the present invention is greater than the compressive strength. Therefore, when designing the cross section of the protective beam, the present invention makes the bending direction of the neutral axis of the protective beam close to the compressed side, that is, the design size of the outer web of the protective beam is larger than the design size of the inner web (for example, the outer web of the protective beam can be designed to be thicker than the thickness of the inner web, or the outer web of the protective beam can be designed to be wider than the width of the inner web) to improve the bending coefficient of the cross section of the protective beam. Compared with the conventional symmetrical structure in the field, the present invention designs the cross section of the composite protective beam of commercial vehicles to be a hollow structure with an asymmetric neutral axis, making full use of the performance differences of the material under different stress states, with stronger load-bearing stability and better lightweight effect.

[0043] Preferably, the cross-section of the above-mentioned commercial vehicle composite protective beam can be rectangular, trapezoidal or other structures.

[0044] When the cross section is rectangular, such as Figure 1 As shown, the thickness of the outer web of the neutral axis asymmetric hollow structure is larger, and the thickness of the inner web is smaller.

[0045] When the cross section is trapezoidal, such as Figure 2 As shown, the length of the outer web of the neutral axis asymmetric hollow structure is larger, and the length of the inner web is smaller.

[0046] Preferably, in order to improve the bending rigidity and stability of the protective beam, longitudinal reinforcement ribs are also provided inside the protective beam.

[0047] Preferably, the composite protective beam for commercial vehicles is provided with a reinforcing sheet on the inner wall of the hollow structure. More preferably, in this embodiment, a reinforcing sheet is provided at a stress concentration location on the inner wall of the hollow structure. The stress concentration location can be obtained through experimental testing. For the embodiment of the present invention, the stress concentration location is as follows: Figure 3 As shown, the present invention only arranges reinforcing sheets at the stress concentration position, which has higher strength and better lightweight effect compared with the prior art that fills the entire interior with foaming material to enhance structural stability.

[0048] Preferably, a reinforcing sheet is also provided at the mounting hole of the composite protective beam of the commercial vehicle. Tests show that the mounting hole is subjected to greater force and the structure is relatively weak. In addition, the strength of the mounting hole will also decrease due to fiber breakage. Therefore, providing a reinforcing sheet at the mounting hole can increase the strength of the protective beam.

[0049] Preferably, the reinforcing sheet is a prepreg comprising epoxy resin and glass fiber fabric. The surface density of the glass fiber is 200 g / m 2 -300g / m 2 The content of epoxy resin in the reinforcing sheet is 35-40%, and the thickness of the reinforcing sheet is 0.2mm-0.3mm. The reinforcing sheet of the present invention adopts the above-mentioned material to improve the bonding strength between the reinforcing sheet and the composite protective beam without using an adhesive.

[0050] Preferably, the reinforcing sheet is bonded to the inner wall via an expansion mandrel. The present invention tightly bonds the reinforcing sheet to the composite material by generating internal pressure through the expansion of the expansion mandrel when heated. In the embodiment of the present invention, the reinforcing sheet is bonded to the inner wall using an expansion mandrel. The expansion mandrel extrude the reinforcing sheet by thermal expansion, and the reinforcing sheet softens at this temperature. The reinforcing sheet and the protective beam use the same base material, and the reinforcing sheet and the inner wall of the protective beam can be better integrated under the pressure of the expansion mandrel. The pasting process is simple, the pressure is uniform, and the reinforcing sheet is firmly pasted. The expansion mandrel can be reused, which greatly reduces the process cost. Compared with the prior art method of directly bonding with an adhesive, the present invention bonds the reinforcing sheet to the inner wall via an expansion mandrel, and the process is simpler, and the bonding is more uniform and firm.

[0051] Preferably, the expansion core mold is an expansion silicone core mold with a hardness range of 30 shoreA-40 shoreA and a volume thermal expansion coefficient range of 5.5-8.0×10 -4 / ℃, temperature resistance -40℃~300℃. Since the expansion core mold will expand when heated, if the expansion force is small, the bonding force between the reinforcement sheet and the inside of the composite protective beam will be insufficient. If the expansion force is too large, the composite protective beam will be squeezed. When the expansion silicone core mold expands due to heat and squeezes the reinforcement sheet and the inner wall of the composite protective beam, it provides greater pressure to ensure the bonding of the reinforcement sheet and the inner wall of the composite protective beam. At the same time, the soft expansion silicone core mold can protect the reinforcement sheet and the protective beam, preventing the expansion silicone core mold from expanding too much and causing deformation or even damage to the composite protective beam.

[0052] In a second aspect, the present invention further provides a method for forming a composite protective beam for a commercial vehicle, comprising the following steps:

[0053] Preparing a thermosetting resin adhesive solution, and immersing the fiber-reinforced material in the thermosetting resin adhesive solution;

[0054] In the molding die, the thermosetting resin glue impregnated with the fiber reinforcement material is heated and cured to obtain the commercial vehicle composite protective beam.

[0055] Preferably, the method for preparing the thermosetting resin glue comprises the following steps:

[0056] According to weight, weigh 100 parts of epoxy resin, 80-90 parts of curing agent, 20-30 parts of composite toughening agent, 2-3 parts of accelerator, 2-3 parts of antioxidant, 0.5-2 parts of internal release agent, and 1-2 parts of color paste;

[0057] Mixing epoxy resin, composite toughening agent, internal mold release agent, antioxidant and color paste to obtain component A;

[0058] Mixing the curing agent and the accelerator to obtain component B;

[0059] The thermosetting resin glue solution can be obtained by mixing component A and component B.

[0060] Preferably, the commercial vehicle composite protective beam of the present invention is obtained by pultrusion. Specifically, after preparing the thermosetting resin glue, the thermosetting resin glue is introduced into the dipping tank of the pultrusion equipment, and then the fiber reinforcement material is introduced into the dipping tank to obtain a mixed material, which is pultruded by the pultrusion equipment.

[0061] Preferably, in the molding mold, the thermosetting resin glue impregnated with the fiber reinforcement material is heated and cured by three-zone heating control, and the temperature of each zone is set as follows: zone one temperature 120℃-130℃, zone two temperature 160℃-170℃, zone three temperature 140℃-150℃, and pultrusion speed: 200-400mm / min.

[0062] Preferably, the fiber-reinforced material is formed by alternating unidirectional continuous glass fiber layers and triaxial glass fiber fabric layers. The fiber-reinforced material of the above structure has good interlayer performance and longitudinal and transverse strength, and solves the problem of vibration fatigue cracking of unidirectional continuous glass fiber beams. The fiber content in the fiber-reinforced material is 65% to 75%.

[0063] Preferably, the ply structure of the fiber-reinforced material of the present embodiment is: +45° / -45° / 90° tri-axial glass fiber fabric layer, 0° continuous glass fiber layer, +45° / -45° / 90° tri-axial glass fiber fabric layer, 0° continuous glass fiber layer, +45° / -45° / 90° tri-axial glass fiber fabric layer. The present embodiment arranges the fiber-reinforced material into the above-mentioned five-layer structure, which can improve the uniformity of the distribution of glass fibers in all directions, thereby improving the strength of the overall structure.

[0064] Preferably, in the entire fiber reinforced material, 0° glass fiber, 45° glass fiber, -45° glass fiber, and 90° glass fiber account for 40%-55%, 15%-20%, 15%-20%, and 15%-20%, respectively. In the embodiment of the present invention, the content of 0° continuous glass fiber in the fiber reinforced material is set relatively large to ensure the longitudinal strength of the protective beam. At the same time, 15%-20% of 45° glass fiber, 15%-20% of -45° glass fiber, and 15%-20% of 90° glass fiber are used to prevent the 0° continuous glass fiber from anti-vibration fatigue cracking, thereby improving the lateral strength of the protective beam.

[0065] Preferably, the specific steps of immersing the fiber-reinforced material into the thermosetting resin glue are as follows:

[0066] According to the above proportions, the unidirectional continuous glass fiber fabric layer and the tri-axial glass fiber fabric layer are placed in a yarn guiding device in the order of +45° / -45° / 90° tri-axial glass fiber fabric layer, 0° continuous glass fiber layer, +45° / -45° / 90° tri-axial glass fiber fabric layer, 0° continuous glass fiber layer, and +45° / -45° / 90° tri-axial glass fiber fabric layer, and the fiber reinforcement material of the above structure is immersed in a thermosetting resin glue solution through the yarn guiding device.

[0067] Preferably, during introduction, a certain distance is maintained between the layers to ensure that the thermosetting resin adhesive can more easily penetrate the fiber reinforcement material.

[0068] Preferably, after obtaining the composite protective cross beam for commercial vehicles, the method further includes the following steps: the composite protective cross beam for commercial vehicles is provided with a reinforcing sheet on the inner wall of the hollow structure.

[0069] Preferably, the present invention provides a reinforcing sheet at the stress concentration location on the inner wall of the hollow structure. The stress concentration location can be obtained through experimental testing. For the embodiment of the present invention, the stress concentration location is as follows: Figure 3 As shown, the present invention only arranges reinforcing sheets at the stress concentration position, which has higher strength and better lightweight effect compared with the prior art that fills the entire interior with foaming material to enhance structural stability.

[0070] Preferably, a reinforcing sheet is also provided at the mounting hole of the composite protective beam of the commercial vehicle. Tests show that the mounting hole is subjected to greater force and the structure is relatively weak. In addition, the strength of the mounting hole will also decrease due to fiber breakage. Therefore, providing a reinforcing sheet at the mounting hole can increase the strength of the protective beam.

[0071] Preferably, the reinforcing sheet is a prepreg comprising epoxy resin and glass fiber fabric. The surface density of the glass fiber is 200 g / m 2 -300g / m 2 The content of epoxy resin in the reinforcing sheet is 35-40%, and the thickness of the reinforcing sheet is 0.2mm-0.3mm. The reinforcing sheet of the present invention adopts the above-mentioned material to improve the bonding strength between the reinforcing sheet and the composite protective beam without using an adhesive.

[0072] Preferably, the method for arranging a reinforcement sheet on the inner wall surrounding the hollow structure of a composite protective beam for commercial vehicles comprises the following steps:

[0073] After preheating, the reinforcing sheet is wound around the expansion core mold, placed on the inner wall surrounding the hollow structure, heated and cured, and after cooling, the expansion core mold is taken out, and the reinforcing sheet is pasted on the inner wall of the hollow structure.

[0074] Since the commercial vehicle composite protective beam of the present invention is made by pultrusion, it is impossible to use ordinary adhesives to stick the reinforcing sheet to the inner wall. The present invention uses an expansion core mold to stick the reinforcing sheet to the inner wall. The expansion core mold extrude the reinforcing sheet by expanding due to heat, and the reinforcing sheet softens at this temperature. The reinforcing sheet and the protective beam use the same substrate. Under the pressure of the expansion core mold, the reinforcing sheet and the inner wall of the protective beam can be well integrated. The pasting process is simple, the pressure is uniform, the reinforcing sheet is firmly pasted, and the expansion core mold can be reused, which greatly reduces the process cost. Compared with the prior art method of directly bonding with adhesives, the present invention uses an expansion core mold to bond the reinforcing sheet to the inner wall, and the process is simpler, and the bonding is more uniform and firm.

[0075] Preferably, the preheating temperature is 50-60°C, the preheating time is 5-8 minutes, and the heating curing process conditions are: 140-160°C, heating for 20-40 minutes. The above heating process conditions can not only expand the expansion core mold to provide greater pressure to the reinforcing sheet and the inner wall; but also the above heating process can further solidify and form the composite protective beam of the commercial vehicle. Since the composite protective beam of the commercial vehicle can be solidified and formed in the above process steps, the pultrusion speed of the composite protective beam of the commercial vehicle in the pultrusion curing molding die can be increased, which can save costs while ensuring the stability of the composite protective beam of the commercial vehicle.

[0076] Preferably, the reinforcing sheet has 5 to 10 winding layers and a thickness of 1 mm to 3 mm.

[0077] The method for forming a composite protective beam for a commercial vehicle according to an embodiment of the present invention specifically comprises the following steps:

[0078] (1) According to the weight ratio, 100 parts of epoxy resin, 80-90 parts of curing agent, 20-30 parts of composite toughening agent, 2-3 parts of accelerator, 2-3 parts of antioxidant, 0.5-2 parts of internal mold release agent, and 1-2 parts of color paste are weighed, and the epoxy resin, composite toughening agent, internal mold release agent, antioxidant, and color paste are added to a mixer and stirred for 20-30 minutes to obtain component A; the curing agent and the accelerator are mixed and stirred for 20 minutes to obtain component B; the A and B components are mixed and stirred for 20-30 minutes to obtain a thermosetting resin glue solution, and the thermosetting resin glue solution is injected into the dipping tank of the pultrusion molding equipment after vacuum degassing;

[0079] (2) The uniaxial continuous glass fiber and the triaxial glass fiber fabric are introduced into a dipping tank through a yarn guide device in proportion and immersed in a thermosetting resin glue solution to obtain a mixed material, and then the mixed material is introduced into a molding mold for heating and curing. After cooling, the commercial vehicle composite protective beam can be obtained.

[0080] The curing molding adopts three-zone heating control, and the temperature of each zone is set as follows: the temperature of zone one is 120°C-130°C, the temperature of zone two is 160°C-170°C, the temperature of zone three is 140°C-150°C, and the pultrusion speed is 200-400mm / min.

[0081] (3) Preheat the reinforcing sheet in an oven at 50 to 60° C. for 5 to 8 minutes, then wrap it around the expansion core mold while it is hot and place it around the inner wall of the hollow structure. The process gap is controlled at 1 to 1.5 mm. Heat it in an oven at 140 to 160° C. for 20 to 40 minutes. After cooling, take out the expansion core mold to complete the pasting of the reinforcing sheet on the inner wall of the hollow structure.

[0082] The following is a description of the commercial vehicle composite protective beam and its forming method according to the present invention through specific embodiments.

[0083] Example 1

[0084] The commercial vehicle composite protective beam provided in Example 1 is a rear lower protective beam of a medium-sized truck.

[0085] The cross-section of the commercial vehicle composite protective beam is a rectangular hollow structure, in which the length of the commercial vehicle composite protective beam is 2360mm, the width is 120mm, the height is 80mm, the thickness of the outer web is 6mm, the thickness of the inner web is 4mm, and the thickness of the left and right wing panels and internal reinforcement ribs is 5mm.

[0086] The thermosetting resin is calculated by weight, and includes 100 parts of bisphenol A type E51 epoxy resin, 85 parts of curing agent, 25 parts of composite toughening agent, 3 parts of accelerator, 2 parts of antioxidant, 1 part of color paste, and 1.5 parts of internal release agent. Among them, the curing agent is methyl tetrahydropropionic anhydride; the composite toughening agent is a mixture of polyhydroxyl functional linear polyether compound 410 and nano core-shell toughened epoxy resin EPX225, the mass ratio is 1:1, the viscosity of polyhydroxyl functional linear polyether compound is 50cp, the viscosity of nano core-shell toughened epoxy resin is 4000cp, and the CSR content is 25%; the accelerator is 2-ethyl 4-methylimidazole; the internal release agent is XY-HG172 release agent; the antioxidant is benzodiquinone.

[0087] The fiber reinforced material includes unidirectional continuous glass fiber and triaxial glass fiber fabric, wherein the fiber content is 70%, and the layer structure thereof from inside to outside is respectively +45° / -45° / 90° triaxial glass fiber fabric layer, 0° continuous glass fiber layer, +45° / -45° / 90° triaxial glass fiber fabric layer, 0° continuous glass fiber layer, +45° / -45° / 90° triaxial glass fiber fabric layer, wherein the 0°, 45°, -45°, 90° fibers account for 52%, 16%, 16%, and 16%, respectively.

[0088] The molding method comprises the following steps:

[0089] (1) According to the weight ratio, 100 parts of bisphenol A type E51 epoxy resin, 85 parts of curing agent, 25 parts of composite toughening agent, 3 parts of accelerator, 2 parts of antioxidant, 1 part of color paste, and 1.5 parts of internal release agent are weighed, and the epoxy resin, composite toughening agent, internal release agent, antioxidant, and color paste are added to a mixer and stirred for 30 minutes to obtain component A; the curing agent and accelerator are mixed and stirred for 20 minutes to obtain component B; components A and B are mixed and stirred for 30 minutes to obtain a thermosetting resin glue solution, and after vacuum degassing, the thermosetting resin glue solution is injected into the dipping tank of the pultrusion molding equipment;

[0090] (2) In proportion, continuous glass fiber and triaxial glass fiber fabric are introduced into a dipping tank through a yarn guide device and immersed in a thermosetting resin glue solution to obtain a mixed material, and then the mixed material is introduced into a molding mold for heating and curing. After cooling, the commercial vehicle composite protective beam 1 is obtained. The mass of the commercial vehicle composite protective beam 1 is 12.1 kg.

[0091] The curing molding adopts three-zone heating control, and the temperature of each zone is set as follows: the temperature of zone 1 is 125°C, the temperature of zone 2 is 165°C, the temperature of zone 3 is 150°C, and the pultrusion speed is 300mm / min.

[0092] Example 2

[0093] A 2 mm thick reinforcement sheet is pasted on the stress concentration position of the inner wall of the cavity of the commercial vehicle composite protective beam 1 of Example 1.

[0094] The method for pasting the reinforcing sheet comprises the following steps:

[0095] Preheat the reinforcing sheet in a 50°C oven for 5 minutes, then wrap it around the expansion core mold while hot, and place it at the stress concentration location of the inner wall of the hollow structure of the commercial vehicle composite protective beam with a process gap of 1mm. Then heat it in a 150°C oven for 30 minutes. After cooling, pull out the silicone core mold to obtain a partially reinforced commercial vehicle composite protective beam 2. The mass of the above-mentioned commercial vehicle composite protective beam 2 is 13.3Kg.

[0096] The reinforcing sheet is epoxy resin / glass fiber fabric prepreg, and the glass fiber surface density is 200g / m 2 , resin content 35%, thickness 0.2mm, winding layer number 10 layers; the expansion mandrel is an expansion silicone mandrel, hardness 35shoreA, volume thermal expansion coefficient 6.6×10 -4 / ℃, operating temperature range is -40℃~300℃.

[0097] Example 3

[0098] The commercial vehicle composite protective beam provided in Example 3 is a front lower protective beam of a medium-sized truck.

[0099] The cross-section of the commercial vehicle composite protective beam is a trapezoidal hollow structure with a length of 2315 mm, a height of 80 mm, a wall thickness of 6 mm, an outer web width of 120 mm, and an inner web width of 90 mm.

[0100] The thermosetting resin is calculated by weight, and includes 100 parts of bisphenol A type E51 epoxy resin, 85 parts of curing agent, 20 parts of composite toughening agent, 3 parts of accelerator, 2 parts of antioxidant, 1.5 parts of internal mold release agent, and 1 part of color paste. Among them, the curing agent is methyl tetrahydropropionic anhydride; the composite toughening agent is a mixture of polyhydroxyl functional linear polyether compound 410 and nano core-shell toughened epoxy resin EPX225, with a mass ratio of 1:1.2, the viscosity of polyhydroxyl functional linear polyether compound is 50cp, the viscosity of nano core-shell toughened epoxy resin is 4000cp, and the CSR content is 25%; the accelerator is 2-ethyl 4-methylimidazole; the internal mold release agent is XY-HG172 mold release agent; and the antioxidant is benzodiquinone.

[0101] The fiber reinforcement material is unidirectional continuous glass fiber and tri-axial glass fiber fabric with a fiber content of 72%. Its layer structure from inside to outside is respectively +45° / -45° / 90° tri-axial glass fiber fabric layer, 0° continuous glass fiber layer, +45° / -45° / 90° tri-axial glass fiber fabric layer, 0° continuous glass fiber layer, +45° / -45° / 90° tri-axial glass fiber composite felt layer, among which 0°, 45°, -45°, and 90° fibers account for 40%, 20%, 20%, and 20% respectively.

[0102] The molding method comprises the following steps:

[0103] (1) According to the weight ratio, 100 parts of bisphenol A type E51 epoxy resin, 85 parts of curing agent, 20 parts of composite toughening agent, 3 parts of accelerator, 2 parts of antioxidant, 1 part of color paste, and 1.5 parts of internal release agent are weighed, and the epoxy resin, composite toughening agent, internal release agent, antioxidant, and color paste are added to a mixer and stirred for 30 minutes to obtain component A; the curing agent and the accelerator are mixed and stirred for 20 minutes to obtain component B; the A and B components are mixed and stirred for 30 minutes to obtain a thermosetting resin glue solution, and after vacuum degassing, the thermosetting resin glue solution is injected into the dipping tank of the pultrusion molding equipment;

[0104] (2) The continuous glass fiber and the triaxial glass fiber fabric are introduced into a dipping tank through a yarn guide device in proportion and immersed in a thermosetting resin glue solution to obtain a mixed material. The mixed material is then introduced into a molding mold for heating and curing. After cooling, the commercial vehicle composite protective beam 3 is obtained.

[0105] The curing molding adopts three-zone heating control, and the temperature of each zone is set as follows: the temperature of zone 1 is 120°C, the temperature of zone 2 is 160°C, the temperature of zone 3 is 150°C, and the pultrusion speed is 300mm / min.

[0106] Example 4

[0107] A 3 mm thick reinforcement sheet is pasted on the inner wall of the cavity of the composite protective beam of the commercial vehicle in Example 3.

[0108] The method for pasting the reinforcing sheet comprises the following steps:

[0109] The reinforcing sheet is preheated in a 50°C oven for 5 minutes, then wrapped around the expansion core mold while hot, and placed at the stress concentration location of the inner wall of the hollow structure of the commercial vehicle composite protective beam with a process gap of 1 mm. It is then placed in a 150°C oven and heated for 30 minutes. After cooling, the silicone core mold is pulled out to obtain a partially reinforced commercial vehicle composite protective beam 4.

[0110] The reinforcing sheet is epoxy resin / glass fiber fabric prepreg, and the surface density of the glass fiber is 300g / m 2 , resin content 35%, reinforcement winding layer number 10 layers. The expansion mandrel is an expansion silicone mandrel with a hardness of 35 shoreA and a volume thermal expansion coefficient of 6.6×10 -4 / ℃, operating temperature range is -40℃~300℃.

[0111] Comparative Example 1

[0112] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 is made of metal material DL510, and the mass of the protective beam made of DL510 is 21.9 kg.

[0113] Comparative Example 2

[0114] The difference between Comparative Example 2 and Example 1 is that the toughening agent used in Comparative Example 2 is liquid nitrile rubber.

[0115] Comparative Example 3

[0116] The difference between Comparative Example 3 and Example 1 is that the composite toughening agent used in Comparative Example 3 is a polyhydroxy functional group linear polyether compound 410.

[0117] Comparative Example 4

[0118] The difference between Comparative Example 4 and Example 1 is that the composite toughening agent used in Comparative Example 4 is nano core-shell toughened epoxy resin EPX225.

[0119] Comparative Example 5

[0120] The difference between Comparative Example 5 and Example 1 is that the fiber reinforcement materials used in Comparative Example 5 are unidirectional continuous fibers and commercially available surface felt, and the layer structure is: surface felt / unidirectional continuous fiber layer / surface felt.

[0121] Comparative Example 6

[0122] The difference between Comparative Example 6 and Example 2 is that: Comparative Example 6 uses polyurethane foam to fill the hollow structure, and the filling density of the polyurethane foam is 0.07 g / cm 3No reinforcement sheet is used for local reinforcement, and the mass is 13.3Kg.

[0123] Comparative Example 7

[0124] The difference between Comparative Example 7 and Example 1 is that the cross-section of the composite protective beam of the commercial vehicle in Comparative Example 7 is a hollow structure symmetrical about the neutral axis, with a length of 2360 mm, a width of 120 mm, a height of 80 mm, an outer web thickness of 5 mm, an inner web thickness of 5 mm, and a left and right wing panel and internal reinforcement rib thickness of 5 mm.

[0125] Test the component specimens of the above-mentioned commercial vehicle composite protective beam:

[0126] (1) Rigidity test: The rear lower guard beam is subjected to a static loading test in accordance with GB11567-2017, with the test loads at points P1 and P3 being 50 kN and at point P2 being 100 kN. The front lower guard beam is subjected to a static loading test in accordance with GB26511-2011, with the test loads at points P1 and P3 being 80 kN and at point P2 being 160 kN. The maximum deformation at each loading point is tested (points P1, P2, and P3 are as follows: Figure 3 As shown, in accordance with GB26511-2011, for the left-right symmetrical lower protection: the distance between point P1 and the end of the protection beam is ≤100 mm, the distance between point P2 and point P3 is ≥350-600 mm, and point P3 is located at the symmetry center of the protection). The smaller the deformation, the greater the structural rigidity and the higher the strength.

[0127] (2) Vibration fatigue test: The parts are fixed on the test bench in the assembled manner, and the vibration frequency is 30 Hz, the vibration acceleration is 3g, and the vibration is performed 1 million times in the order of up and down, left and right, and front and back to detect whether the product has any abnormalities such as cracking and looseness.

[0128] (3) High temperature drop hammer impact test: It is carried out in accordance with the drop hammer test method in QC / T15-1992, with a hammer head radius of 25 mm, a hammer body mass of 500 g, an impact height of 1 mm, and a test temperature of 90°C. The parts are tested for deformation, cracking, and other abnormalities.

[0129] The test results are shown in Tables 1 and 2 below:

[0130] Table 1 Rigidity test results

[0131]

[0132]

[0133] Table 2 Other test results

[0134] Serial number Vibration fatigue test High temperature drop hammer impact Example 1 No abnormality No abnormality Example 2 No abnormality No abnormality Example 3 No abnormality No abnormality Example 4 No abnormality No abnormality Comparative Example 1 No abnormality No abnormality Comparative Example 2 No abnormality There are obvious dents on the surface Comparative Example 3 No abnormality There are obvious dents on the surface Comparative Example 4 No abnormality No abnormality Comparative Example 5 Longitudinal cracking No abnormality Comparative Example 6 No abnormality No abnormality Comparative Example 7 No abnormality No abnormality

[0135] From the above test results, we can see that:

[0136] (1) The composite protective beam made of a composite material including a thermosetting resin and a fiber-reinforced material in the present invention has a weight reduction of 47% compared with the metal protective beam supported by metal DL510 in the prior art, thereby achieving better lightweighting. Moreover, in terms of rigidity, fatigue resistance, impact resistance and other properties, the composite protective beam can almost maintain the same performance as the metal protective beam. However, the composite protective beam is more excellent in corrosion resistance.

[0137] (2) After the composite protective beam of the present invention is locally reinforced (ie, Example 2), its rigidity is significantly better than that of the metal protective beam, and its weight is significantly lighter than that of the metal protective beam.

[0138] (3) From the comparison between Example 1 and Comparative Examples 2, 3, and 4, the composite toughening agent of the present invention adopts a mixture of a polyhydroxy functional linear polyether compound 410 and a nano-core-shell toughened epoxy resin EPX225, which has better performance than the toughening agents commonly used in the prior art, and the composite protective beam obtained by using the polyhydroxy functional linear polyether compound 410 and the nano-core-shell toughened epoxy resin EPX225 alone.

[0139] (4) From the comparison between Example 1 and Comparative Example 5, compared with the structure of surface felt / unidirectional continuous fiber layer / surface felt, the fiber reinforced material used in the present invention can improve the structural strength and fatigue resistance of the protective beam.

[0140] (5) From the comparison between Example 2 and Comparative Example 6, it can be seen that the present invention arranges a reinforcement plate at the stress concentration location of the inner wall of the hollow structure of the protective beam. Compared with the prior art of filling with foam polyurethane, the structural strength is higher under the condition of the same quality.

[0141] (6) From the comparison between Example 1 and Comparative Example 7, it can be seen that the cross-section of the protective beam is set to be an asymmetric structure about the neutral axis in the present invention, which can increase the rigidity of the protective beam and improve the structural strength of the protective beam.

[0142] It should be noted that, in the present invention, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0143] The present invention is not limited to the above-mentioned embodiments. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention. The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. A composite protective beam for commercial vehicles, characterized in that: The commercial vehicle composite protective beam is made of a composite material including a thermosetting resin and a fiber-reinforced material; Wherein, the thermosetting resin includes bisphenol A epoxy resin material, and the fiber reinforcement material includes a unidirectional continuous glass fiber layer and a triaxial glass fiber fabric layer.

2. The composite protective beam for commercial vehicles according to claim 1, characterized in that: Calculated by weight, the bisphenol A epoxy resin material includes 100 parts of epoxy resin, 80-90 parts of curing agent, 20-30 parts of composite toughening agent, 2-3 parts of accelerator, 2-3 parts of antioxidant, 0.5-2 parts of internal release agent and 1-2 parts of color paste.

3. The composite protective beam for commercial vehicles according to claim 2, characterized in that: The composite toughening agent comprises a polyhydroxyl functional group linear polyether compound and a nano core-shell toughening epoxy resin.

4. The composite protective beam for commercial vehicles according to claim 3, characterized in that: The mass ratio of the polyhydroxyl functional linear polyether compound to the nano core-shell toughened epoxy resin is 1:(0.5-1.5).

5. The composite protective beam for commercial vehicles according to claim 1, characterized in that: The fiber reinforcement material is formed by alternately stacking unidirectional continuous glass fiber layers and triaxial glass fiber fabric layers.

6. The composite protective beam for commercial vehicles according to claim 1, characterized in that: The cross section of the commercial vehicle composite protective beam is an asymmetric hollow structure about the neutral axis.

7. The composite protective beam for commercial vehicles according to claim 6, characterized in that: The commercial vehicle composite protective cross beam is provided with a reinforcement sheet on the inner wall of the hollow structure.

8. The composite protective beam for commercial vehicles according to claim 7, characterized in that: The reinforcing sheet is a prepreg comprising epoxy resin and glass fiber fabric.

9. The composite protective beam for commercial vehicles according to claim 7, characterized in that: The reinforcing sheet is bonded to the inner wall via an expansion core mold.

10. A method for forming a composite protective beam for a commercial vehicle as claimed in claim 1, characterized in that: The following steps are involved: Preparing a thermosetting resin adhesive solution, and immersing the fiber-reinforced material in the thermosetting resin adhesive solution; In the molding die, the thermosetting resin glue impregnated with the fiber reinforcement material is heated and cured to obtain the commercial vehicle composite protective beam.

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