Collision resistance analysis and optimization design method of steel and UHPC combined anti-collision device

Abstract

The invention relates to a crashworthiness analysis and optimization design method of a steel and UHPC (Ultra High Performance Concrete) combined anti-collision device. According to the anti-collision performance analysis method, the resistance-collision depth relation of the inner core structure, the top steel plate, the bottom steel plate and the outer steel plate is considered at the same time, the calculation method is scientific, the calculation result is safe and reliable, compared with a traditional mode depending on a refined finite element model, the method can rapidly judge the anti-collision performance of the anti-collision device, a large amount of calculation cost and time are saved, and the calculation efficiency is improved. And actual engineering requirements are met. The design method is optimized, the relation between ship resistance and collision depth and the relation between anti-collision device resistance and collision depth are combined, or the relation between ship resistance and collision depth, the relation between anti-collision device resistance and collision depth and the relation between pier resistance and collision depth are combined, and the peak collision force and the maximum collision depth of the anti-collision device can be accurately predicted according to the ship speed and the ship drainage tonnage. According to the method, the design scheme of the anti-collision device can be rapidly adjusted and optimized in the preliminary design stage, and efficient and accurate design is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of analysis and design of a steel and UHPC combined anti-collision device, and in particular to a collision resistance analysis and optimization design method for a steel and UHPC combined anti-collision device. Background Art

[0002] With the rapid development of social economy, the role of bridges in transportation is becoming increasingly important. As an important part of infrastructure, the safety of bridges is directly related to the smooth flow of transportation and the safety of people's lives and property. However, bridges face many safety hazards during their service, especially the threats to bridge structures from factors such as traffic accidents and natural disasters. Among them, vicious ship collisions have occurred frequently in recent years, seriously affecting traffic safety and the long-term use of bridges, causing a large number of casualties, bridge collapses, economic losses, and widespread social impacts.

[0003] In order to effectively prevent damage to bridges caused by ship collisions, traditional bridge anti-collision devices are usually designed with steel structures. Steel structure anti-collision devices have high strength and good plastic deformation ability, which can effectively absorb energy and alleviate the transmission of collision force during the collision process, thereby protecting the bridge. However, steel structure anti-collision devices also have some defects, such as poor durability and easy performance degradation due to environmental corrosion, which increases maintenance costs and replacement frequency.

[0004] In this context, ultra-high performance concrete (UHPC), as a new type of material, has gradually been used in bridge construction and anti-collision design due to its excellent mechanical properties, durability and wear resistance. Therefore, researchers proposed the idea of ​​combining steel with UHPC to form a steel and UHPC combined anti-collision device. And the results show that during the ship collision, the UHPC panel can effectively prevent the anti-collision device from being punctured and prevent local damage to the anti-collision device, thereby driving more steel components to undergo plastic deformation to increase energy absorption and significantly improve the energy consumption effect of the anti-collision device. This combination device makes full use of the respective advantages of steel and UHPC to improve the overall protection performance of the anti-collision device.

[0005] However, the current crashworthiness assessment and design of steel and UHPC combined anti-collision devices mainly rely on the engineering experience of researchers. Traditional design methods often rely on physical experiments or high-precision finite element simulations for repeated optimization and adjustment. Each optimization requires re-establishing a refined finite element model of the ship-bridge-anti-collision device and performing a large amount of calculations. Since the number of grids in the entire collision model may reach millions, each analysis requires dozens of hours of solution with the help of a supercomputer, which greatly limits the efficiency of design and optimization. In addition, none of the publicly available technologies provide relevant design methods, resulting in a cumbersome and inefficient overall design process for the steel and UHPC combined anti-collision device, which greatly limits its application.

[0006] In summary, there is an urgent need for a new crashworthiness analysis and design method for steel-UHPC combined anti-collision devices, which can quickly predict the crashworthiness of anti-collision devices and provide an efficient optimization design solution, thereby solving the deficiencies in the existing technology and improving the design efficiency of anti-collision devices. Summary of the invention

[0007] The purpose of the present invention is to provide a crashworthiness analysis and optimization design method for a steel-UHPC combined crashproof device, aiming to solve the problem that there is no efficient design method to rely on at present, overcome the fact that the crashworthiness evaluation and design of the steel and UHPC combined crashproof device in the prior art mainly rely on the engineering experience of researchers and rely on physical experiments or high-precision finite element simulation for repeated optimization and adjustment, and improve the design rationality and efficiency of the steel-UHPC combined crashproof device. The specific technical scheme is as follows:

[0008] In a first aspect, the present invention provides a method for analyzing the crashworthiness of a steel and UHPC combined crashproof device, comprising the following steps:

[0009] S1. Determine the structural dimension parameters of the steel and UHPC combined anti-collision device in the proposed design; the steel and UHPC combined anti-collision device comprises: a UHPC panel, a box body and an inner core structure, the box body comprises a top steel plate, a bottom steel plate, an inner steel plate and an outer steel plate, the top steel plate is connected to the top of the inner steel plate and the outer steel plate, the bottom steel plate is connected to the bottom of the inner steel plate and the outer steel plate, the UHPC panel is connected to the outer side of the outer steel plate and the inner steel plate, and the inner core structure is arranged in the box body; when a ship collides with the anti-collision device, the UHPC panel can drive the outer steel plate, the top steel plate, the bottom steel plate and the inner core structure to participate in deformation to absorb the initial kinetic energy of the ship;

[0010] S2. Calculate the collision depth δ according to the structural dimensions of the proposed steel and UHPC combined anti-collision device. n Resistance F of the lower top steel plate fold1 , resistance F of bottom steel plate fold2 , the overall resistance of the inner core structure F t And the resistance of the outer steel plate Fpunch ;

[0011] S3, will hit the depth δ n Resistance F of the lower top steel plate fold1 , resistance F of bottom steel plate fold2 , the overall resistance of the inner core structure F t And the resistance of the outer steel plate F punch Sum and determine the impact depth δ n Total resistance of the lower anti-collision device P f , where P f =F t +F fold1 +F fold2 +F punch ;

[0012] S4. Determine the impact depth δ n Is it greater than or equal to the total deformable width L of the anti-collision device? If not, the collision depth δ n Iterate, and then repeat steps S2, S3 and S4; if so, then according to all the collision depths δ n And the impact depth δ n The total resistance P of the corresponding anti-collision device f The resistance-impact depth curve P of the anti-collision device f (δ n );

[0013] S5. According to the anti-collision device's resistance-impact depth curve P f (δ n ) is integrated to obtain the energy-impact depth curve E of the anti-collision device f (δ n ),in

[0014] The present invention provides a crash resistance analysis method for a steel and UHPC combined crash resistance device, which simultaneously considers the resistance-impact depth relationship of the inner core structure, the top steel plate, the bottom steel plate and the outer steel plate. The calculation method is scientific and the calculation result is safe and reliable. Compared with the traditional method that relies on a refined finite element model, the method can quickly judge the crash resistance of the crash resistance device, save a lot of calculation cost and time, and is suitable for actual engineering needs.

[0015] In the above technical solution, the inner core structure preferably adopts vertical circular tubes filled with foam arranged in layers, and the number of single-layer circular tubes participating in the deformation when the ship hits is n0, and the number of layers is n1;

[0016] The overall resistance F of the inner core structure in step S2 t The calculation process is as follows:

[0017] S2A1, according to the impact depth δ n Determine the impact depth δ of a single round tubet , the impact depth of a single circular tube δ t =δ n / n1;

[0018] S2A2, according to the impact depth δ of a single round tube t , the structural dimensions and material properties of the anti-collision device are used to calculate the resistance F of a single hollow circular tube in the inner core structure. tube ;

[0019] S2A3, according to the impact depth δ of a single round tube t , the structural dimensions and material properties of the anti-collision device are used to calculate the resistance F of the foam in a single circular tube in the inner core structure. foam ;

[0020] S2A4, according to the resistance F of a single empty round tube in the inner core structure tube and the resistance F of the foam in a single tube foam Sum and obtain the resistance F of a single foam-filled circular tube in the inner core structure i , where F i =F tube +F foam ;

[0021] S2A5, based on the resistance F of a single foam-filled circular tube i and impact depth δ n The number of single-layer circular tubes participating in the deformation n o Calculate the overall resistance F of the inner core structure t , where F t =n0F i .

[0022] In the above technical solution, the resistance F of the single empty round tube in step S2A2 is preferably tube The calculation process is as follows:

[0023] A2.1. Calculation of the effective yield stress σ of the circular tube in the inner core structure y ,in σ y0 is the yield stress of the circular tube;

[0024] A2.2. Calculate the initial resistance F of a single empty circular tube in the inner core structure tube，0 :

[0025]

[0026] Where R is the radius of the circular tube in the inner core structure; k t is the vertical constraint coefficient of the tube group structure; M0 is the full plastic bending moment in the lateral crushing of the circular tube, where t t is the thickness of the tube; h2 is the length of the tube;

[0027] A2.3. Calculate the resistance F of a single hollow circular tube in the inner core structure tube :

[0028]

[0029] Among them, cos is the cosine function; sin is the sine function; γ is the angle between the tangent line and the vertical line at the intersection of the hardened section and the rigid section in the transverse crushing of the circular tube. The calculation method of γ is:

[0030] First, assume that λ = F tube / F tube，0 and q 2 =ζ 2 F tube / 2E P I, combined with the resistance F of a single hollow circular tube in the inner core structure tube The calculation formula and the initial resistance F of the inner core structure empty circular tube tube，0 The calculation formula can be obtained: Among them, λ, q, ζ and m are the deformation coefficients of the hardened section of the round tube after considering the mutual constraints of multiple round tubes; E P is the plastic hardening modulus of the circular tube; I is the moment of inertia of the circular tube;

[0031] Then, substitute λ and m into the calculation formula of the angle γ between the tangent line and the vertical line at the intersection of the hardened section and the rigid section in the transverse crushing of the circular tube to obtain the angle γ. The calculation formula of the angle γ between the tangent line and the vertical line at the intersection of the hardened section and the rigid section in the transverse crushing of the circular tube is:

[0032]

[0033] Among them, θ is the angle operation parameter;

[0034] The resistance F of the foam in the single empty tube in step S2A3 foam The calculation formula is as follows:

[0035]

[0036] Where D is the diameter of the tube; h2 is the length of the tube; σ p is the platform stress of the foam; k and n are the material constants of the foam; ε D is the densification strain of the foam; where k, n and ε D Determined according to the stress-strain curve of the foam, the function of the foam stress-strain curve is:

[0037]

[0038] Where ε is the strain of the foam; σf is the stress of the foam at strain ε.

[0039] In the above technical solution, preferably, during the collision between the ship and the anti-collision device, the influence of the strain rate on the round tube steel is considered, and the yield stress σ of the round tube is y0 The calculation formula is: in, is the reference strain rate under ship impact; P and X are the strain rate parameters of round tube steel; σ′ y0 is the yield strength of round tube steel in quasi-static uniaxial test.

[0040] In the above technical solution, preferably, during the collision between the ship and the anti-collision device, the influence of the strain rate on the foam is considered, and the formula considering the strain rate effect of the foam is: Among them, σ p (ε) is the nonlinear expression of foam stress-strain after considering the impact effect; σ(ε) is the nonlinear expression of foam stress-strain under quasi-static action; ε is the strain of the foam; is the strain rate of the quasi-static uniaxial test; is the reference strain rate for simulating the anti-collision device under the impact of a ship; a and b are the strain rate parameters of the foam.

[0041] The calculation method of the inner core structure resistance-impact depth relationship fully considers the impact of the impact depth and the mutual constraint between the group of pipes, and uses the layout of the steel pipes, the diameter and length of the round pipes, and the strength of the steel and polyurethane as parameters to obtain a resistance-impact depth relationship that accurately reflects the mutual constraint effect of the group of pipes. This calculation method is scientific and rigorous, can better reflect the structural performance, and provides a reliable basis for the collision resistance analysis and optimization design of the anti-collision device.

[0042] In the above technical solution, the resistance F of the outer steel plate in step S2 is preferably punch The calculation process is as follows:

[0043] S2B1. Calculate the critical impact depth Δ0 before the outer steel plate breaks and fails:

[0044]

[0045] Among them, l0 is the length of the outer steel plate before impact; ε0 is the critical strain of the outer steel plate steel;

[0046] S2B2, according to the critical impact depth Δ0 and impact depth δ n Calculate the resistance F of the outer steel plate punch , the calculation steps are:

[0047]

[0048] Where h1 is the height of the anti-collision device; σ y3is the yield stress of the outer steel plate; t punch is the thickness of the outer steel plate; C is the length of the top steel plate and the bottom steel plate; n2 is the impact depth δ n The number of cracks after the lower steel plate breaks, n2 is 2 to 4; l is the impact depth δ n The length of the lower crack, l = δ n / tanθ1; θ1 is half of the expansion angle of the ship; μ is the friction coefficient between the outer steel plate and the ship, and μ takes a value of 0.15~0.3.

[0049] In the above technical solution, the resistance F of the top steel plate in step S2 is preferably fold1 The calculation process is as follows:

[0050]

[0051] Among them, π is the ratio of circumference to diameter; σ is the ratio of circumference to diameter. y1 is the yield stress of the top steel plate; t f1 is the thickness of the top steel plate, C is the length of the top steel plate and the bottom steel plate; H1 is the folding wavelength of the top steel plate after collision;

[0052] The resistance F of the bottom steel plate in step S2 fold2 The calculation process is as follows:

[0053]

[0054] Among them, σ y2 is the yield stress of the bottom steel plate; t f2 is the thickness of the bottom steel plate; C is the length of the top and bottom steel plates; H2 is the folding wavelength of the bottom steel plate after collision.

[0055] Further preferably, the calculation formula of the folding wavelength H1 after the top steel plate hits is:

[0056]

[0057] Further preferably, the calculation formula of the folding wavelength H2 after the bottom steel plate hits is:

[0058]

[0059] In a second aspect, the present invention provides an optimization design method for a steel and UHPC combined anti-collision device, comprising the following steps:

[0060] SO1: According to the crashworthiness analysis method of the steel and UHPC combined crashproof device, the resistance-impact depth curve and energy-impact depth curve of the proposed steel and UHPC combined crashproof device are first determined, and the energy-local peak collision force curve of the crashproof device is further derived based on the two curves;

[0061] At the same time, according to the navigation conditions required by the defense, the maximum displacement tonnage of navigable ships is determined. v , navigation speed v0 and additional mass coefficient C m Based on these parameters, the total initial energy E0 required for defense is calculated as:

[0062]

[0063] At the same time, the ship's configuration is determined according to the ship type, and the ship's resistance-impact depth curve is obtained from it, and then the ship's energy-impact depth curve is derived; the ship's energy-local peak collision force curve is determined through the ship's resistance-impact depth curve and energy-impact depth curve;

[0064] When the energy absorbed by the bridge pier is not considered, the total energy-local peak collision force curve can be derived by combining the energy-local peak collision force curve of the anti-collision device with the energy-local peak collision force curve of the ship;

[0065] When considering the energy absorption of the bridge pier, it is necessary to first determine the resistance-impact depth curve of the bridge pier based on the structural characteristics of the bridge pier, and derive its energy-impact depth curve and energy-local peak impact force curve; then, by integrating the energy-local peak impact force curves of the anti-collision device, the ship and the bridge pier, the total energy-local peak impact force curve is determined;

[0066] S02: Substitute the initial total energy E0 to be protected into the total energy-local peak collision force curve to determine the local peak collision force P when absorbing the initial total energy t , according to the local peak collision force P t Calculate the energy E that the anti-collision device needs to absorb f ; Then the anti-collision device energy-impact depth curve and the energy E that the anti-collision device needs to absorb are f , determine the maximum collision depth a of the anti-collision device f ;

[0067] S03: Determine the local peak collision force P t and the maximum collision depth of the anti-collision device a f Whether it meets the requirements: If the local peak collision force P t and the maximum collision depth of the anti-collision device a f If both meet the requirements, the anti-collision device design is completed; if the local peak collision force P t and the maximum collision depth of the anti-collision device a f If at least one of the above does not meet the requirements, the anti-collision device needs to be optimized and designed. After optimization, the total energy-local peak collision force curve in step S01 is updated, and steps S02-S03 are repeated until the local peak collision force P t and the maximum collision depth of the anti-collision device a f All requirements are met and the optimization design of the anti-collision device is completed;

[0068] Among them, the local peak collision force P is determined t The way to meet the requirements is to set the local peak collision force P t The collision force P between the ship and the bridge pier without considering the anti-collision device v-b For comparison, if P is satisfied t ≤(1-λ p )×P v-b , it means that the proposed anti-collision device meets the requirements for reducing the ship collision force; among them, δ n is the ship impact force reduction rate that needs to be met;

[0069] Determine the maximum collision depth a of the anti-collision device f The way to meet the demand is: the maximum collision depth of the anti-collision device is a f Compared with the total deformable width L of the proposed anti-collision device, if a is satisfied f ≤λ a ×L, it means that the proposed anti-collision device meets the requirements for reducing the ship collision force; where λ a The maximum deformation rate allowed for the anti-collision device.

[0070] The present invention provides an optimization design method for a steel and UHPC combined anti-collision device, which combines the relationship between the ship's resistance-collision depth and the anti-collision device's resistance-collision depth, or combines the relationship between the ship's resistance-collision depth, the anti-collision device's resistance-collision depth, and the resistance-collision depth of the pier, and can accurately predict the peak collision force and the maximum collision depth of the anti-collision device according to the ship speed and the ship's displacement tonnage. This method can quickly adjust and optimize the design of the anti-collision device in the preliminary design stage to achieve efficient and accurate design. Compared with the traditional optimization process that relies on refined numerical models, this method is faster and more convenient, avoiding the time and cost consumption caused by frequent modeling, calculations, and adjustments in traditional methods, and significantly improving the design efficiency.

[0071] Preferably, the collision force P between the ship and the bridge pier under the anti-collision device is not considered. v-b The calculation formula is:

[0072] P v-b = zηβv0[(1+C M )m v ] 0.62 ;

[0073] Among them, z is the ship collision force coefficient; η is the correction factor of geometric dimensions; β is the correction factor of impact angle.

[0074] Compared with the prior art, the present invention has the following beneficial effects:

[0075] 1. The present invention provides a crash resistance analysis method for a steel and UHPC combined crash resistance device, which simultaneously considers the resistance-impact depth relationship of the inner core structure, top steel plate, bottom steel plate and outer steel plate. The calculation method is scientific and the calculation results are safe and reliable. Compared with the traditional method that relies on a refined finite element model, the present method can quickly determine the crash resistance of the crash resistance device, saving a lot of calculation cost and time, and is suitable for actual engineering needs.

[0076] 2. The present invention provides a crash resistance analysis method for a steel and UHPC combined crash protection device. The calculation method for the inner core structure resistance-crash depth relationship fully considers the impact of the collision depth and the mutual constraint between the group of tubes, and uses the arrangement of the round tubes, the diameter and length of the round tubes, and the strength of the steel and polyurethane as parameters to obtain a resistance-crash depth relationship that accurately reflects the mutual constraint effect of the group of tubes. The calculation method is scientific and rigorous, can better reflect the structural performance, and provides a reliable basis for the crash resistance analysis and optimization design of the crash protection device.

[0077] 3. The present invention provides an optimization design method for a steel and UHPC combined anti-collision device, which combines the relationship between the ship's resistance-collision depth and the anti-collision device's resistance-collision depth, or combines the relationship between the ship's resistance-collision depth, the anti-collision device's resistance-collision depth, and the resistance-collision depth of the pier, and can accurately predict the peak collision force and the maximum collision depth of the anti-collision device according to the ship speed and the ship's displacement tonnage. This method can quickly adjust and optimize the design of the anti-collision device in the preliminary design stage to achieve efficient and accurate design. Compared with the traditional optimization process that relies on refined numerical models, this method is faster and more convenient, avoiding the time and cost consumption caused by frequent modeling, calculations, and adjustments in traditional methods, and significantly improving the design efficiency.

[0078] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0080] Figure 1 It is a schematic diagram of the internal structure section of the steel and UHPC combined anti-collision device;

[0081] Figure 2 It is a schematic diagram of the structure of the steel and UHPC combined anti-collision device under ship impact;

[0082] Figure 3 It is a flow chart of the crashworthiness analysis method of the steel and UHPC combined crashproof device of the present invention;

[0083] Figure 4 It is a schematic diagram of the deformation mode of a single hollow circular tube in the inner core structure;

[0084] Figure 5 This is a schematic diagram of the deformation of the 1 / 4 model of the circular tube in the inner core structure;

[0085] Figure 6 It is a flow chart of the optimization design method of the steel and UHPC combined anti-collision device of the present invention;

[0086] Figure 7 It is a curve diagram of the relationship between the resistance and impact depth of the energy-absorbing components in the proposed steel and UHPC combined anti-collision device;

[0087] Figure 8 It is a comparison of the force-impact depth and energy-impact depth relationship curves of the proposed steel and UHPC combined anti-collision device (based on the proposed crashworthiness analysis method and refined finite element model);

[0088] Fig. 9 It is the resistance-collision depth relationship curve of the proposed steel and UHPC combined anti-collision device and the ship;

[0089] Fig.10 It is a schematic diagram of the collision response prediction of the proposed steel and UHPC combined anti-collision device;

[0090] Fig.11 This is a schematic diagram of the collision response prediction of the steel and UHPC combined anti-collision device after increasing the thickness of the steel plate;

[0091] Fig.12 It is a schematic diagram of the collision response prediction of the steel and UHPC combined anti-collision device after increasing the number of inner core structure layers.

[0092] Markings in the figure: 1, bridge pier; 2, ship; 100, UHPC panel; 110, inner core structure; 111, round tube; 112, foam; 121, top steel plate; 122, bottom steel plate; 131, outer steel plate; 132, inner steel plate; 140, flange connection plate; 150, fender. DETAILED DESCRIPTION

[0093] The present invention is further described in detail below in conjunction with specific embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0094] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating the orientation or position relationship such as "up", "down", "left", "right", "center", "inside", "outside", etc. are all expressions based on the orientation or position relationship shown in the drawings, or are the orientation or position relationship when the invented product / equipment / device is usually used. These terms of orientation or position relationship are only for the convenience of describing the scheme of the present invention or simplifying the description in the specific embodiments, so as to facilitate the technicians to quickly understand the scheme, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific position relationship, and therefore cannot be understood as a limitation on the present invention.

[0095] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding devices / components / elements are required to be absolutely horizontal or vertical or overhanging or parallel, but may be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but may be slightly tilted. Alternatively, it can be simplified to mean that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the scheme of the present invention.

[0096] In addition, the expressions “first”, “second”, “third”, etc., which appear in the terms, are merely used to distinguish the description of the same or similar components and should not be understood as emphasizing or implying the relative importance of specific components.

[0097] In addition, in the description of the embodiments of the present invention, "several", "plurality" and "a number" represent at least 2. It can be any number such as 2, 3, 4, 5, 6, 7, 8, 9, and even more than 9.

[0098] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, the terms "set", "install", "connect", "connected", "provided with", "laid", and "arranged" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, and can be welding, riveting, bolting, threading, and other commonly used connection means in the field. This connection can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.

[0099] Example 1

[0100] This embodiment provides a method for analyzing the crashworthiness of a steel and UHPC combined crashproof device. Figure 1 and Figure 2 The steel and UHPC combined anti-collision device includes: a UHPC panel 100, a box body and an inner core structure 110. The box body includes a top steel plate 121, a bottom steel plate 122, an outer steel plate 131 and an inner steel plate 132. The top steel plate 121 is connected to the top of the outer steel plate 131 and the inner steel plate 132, the bottom steel plate 122 is connected to the bottom of the outer steel plate 131 and the inner steel plate 132, the inner core structure 110 is arranged in the box body, and the UHPC panel 100 is connected to the outside of the outer steel plate 131 and the inner steel plate 132.

[0101] Further, such as Figure 1 As shown, a flange connecting plate 140 etc. may also be provided in the box body to divide the anti-collision device into anti-ship collision device units. The anti-ship collision device units are also box-type structures. A plurality of anti-ship collision device units are connected into a whole through the flange connecting plate 140.

[0102] Furthermore, a plurality of fenders 150 may be provided on the outer side of the inner steel plate 132 , and the inner side of the fenders 150 is the bridge pier 1 .

[0103] Preferably, the inner core structure 110 adopts vertical circular tubes 111 filled with foam 112 arranged in layers. Compared with the traditional configuration, the vertical circular tubes 111 filled with foam 112 have better performance effects.

[0104] like Figure 2 As shown, when the ship 2 loses control and hits the bridge pier 1, the ship 2 will directly hit the UHPC panel 100 on the outside of the anti-collision device, and then the outer steel plate 131, the top steel plate 121, the bottom steel plate 122 and the inner core structure 110 will deform to absorb the kinetic energy of the ship. During the collision, the inner steel plate 132 generally does not participate in the deformation and energy absorption. The UHPC panel 100 can prevent the anti-collision device from being pierced and effectively transfer the impact force to the internal energy-consuming structure, thereby reducing the impact force of the ship 2 on the bridge pier 1; in daily service, the UHPC panel 100 can also prevent floating objects from scratching the internal steel plate.

[0105] In order to ensure the safe application of the steel and UHPC combined anti-collision device in bridge anti-collision, this embodiment provides a method for analyzing the anti-collision performance of the steel and UHPC combined anti-collision device, such as Figure 3 As shown, the crash resistance analysis method of the steel and UHPC combined crashproof device includes the following steps:

[0106] S1. Determine the structural dimension parameters of the steel and UHPC combined anti-collision device in the proposed design; Figure 1 and Figure 2As shown, preferably, the inner core structure adopts a layered vertical circular tube filled with foam, further, the filling foam adopts polyurethane foam, the diameter of the circular tube is D, and in the collision of the ship 2, the number of single-layer circular tubes participating in the deformation is n0, and the number of layers is n1; the height of the steel and UHPC combined anti-collision device is h1, and the overall deformable width is L=n1×D;

[0107] S2. Calculate the collision depth δ according to the proposed structural dimensions of the steel and UHPC combined anti-collision device n Calculate the resistance F of the top steel plate fold1 , resistance F of bottom steel plate fold2 , the overall resistance of the inner core structure F t And the resistance of the outer steel plate F punch ; where, assuming the impact depth δ n It is the impact depth of the anti-collision device, the impact depth of the outer steel plate, and the impact depth of the inner core structure.

[0108] Preferably, in step S2, the overall resistance F of the inner core structure t The calculation process is as follows:

[0109] S2A1, according to the impact depth δ n Determine the impact depth δ of a single vertical circular tube t , where δ t =δ n / n1;

[0110] S2A2, according to the impact depth δ of a single vertical circular tube t , the structural dimensions and material properties of the anti-collision device are used to calculate the resistance F of a single hollow circular tube in the inner core structure. tube ;

[0111] The resistance F of the single empty round tube in step S2A2 tube The calculation process is as follows:

[0112] A2.1. Calculation of the effective yield stress σ of the circular tube in the inner core structure y ,in σ y0 is the yield stress of the circular tube;

[0113] Further preferably, during the collision between the ship and the anti-collision device, considering the influence of the strain rate on the round tube steel, the yield stress σ of the round tube is y0 The calculation formula is: in, is the reference strain rate under ship impact; P and X are the strain rate parameters of round tube steel; σ′ y0 is the yield strength of the round tube steel in the quasi-static uniaxial test;

[0114] A2.2. Calculate the initial resistance F of a single empty circular tube in the inner core structure tube，0 :

[0115]

[0116] Where R is the radius of the circular tube in the inner core structure; k t is the vertical constraint coefficient of the group pipe structure, preferably, k t The value is 0.05~0.1; M0 is the full plastic bending moment in the transverse crushing of the circular tube, t t is the thickness of the tube; h2 is the length of the tube;

[0117] A2.3. Calculate the resistance F of a single hollow circular tube in the inner core structure tube :

[0118]

[0119] Among them, γ is the angle between the tangent line and the vertical line at the intersection of the hardened section and the rigid section in the transverse crushing of the circular tube, such as Figure 4 and Figure 5 As shown; cos is the cosine function; sin is the sine function;

[0120] like Figure 4 As shown in Figure 1, when a single empty circular tube is crushed, a collapse characterized by a six-hinge deformation mode will occur, generating plastic hinges such as A, A′ and B. Due to the symmetry of the circular tube under lateral compression, a 1 / 4 model AB consisting of a rigid segment AQ and a hardened segment BQ will be formed during the deformation process, as shown in Figure 1. Figure 5 As shown, the angle between the tangent line of the intersection of the rigid segment AQ and the hardened segment BQ and the vertical line is γ, and the angle γ between the tangent line of the intersection of the rigid segment AQ and the hardened segment BQ and the vertical line can be obtained by finite element simulation or physical test. In order to facilitate the calculation of γ, it is further preferred that the angle γ between the tangent line of the intersection of the hardened segment and the rigid segment and the vertical line in the transverse crushing of the circular tube is calculated as follows:

[0121] First, assume that λ = F tube / F tube，0 and q 2 =ζ 2 F tube / 2E P I, combined with the resistance F of a single hollow circular tube in the inner core structure tube Formula and initial resistance F of a single empty circular tube tube，0 Formula, we can get: Among them, λ, q, ζ and m are the deformation coefficients of the hardened section of the round tube after considering the mutual constraints of multiple round tubes; E P is the plastic hardening modulus of the circular tube; I is the moment of inertia of the circular tube;

[0122] Then, substitute λ and m into the calculation formula of the angle γ between the tangent line and the vertical line at the intersection of the hardened section and the rigid section in the transverse crushing of the circular tube to obtain the angle γ. The calculation formula of the angle γ between the tangent line and the vertical line at the intersection of the hardened section and the rigid section in the transverse crushing of the circular tube is:

[0123]

[0124] Among them, θ is the angle calculation parameter.

[0125] S2A3, according to the impact depth δ of a single round tube t , the structural dimensions and material properties of the anti-collision device are used to calculate the resistance F of the foam in a single circular tube in the inner core structure. foam ;

[0126] Preferably, the resistance F of the foam in the single empty circular tube in step S2A3 is foam The calculation formula is as follows:

[0127]

[0128] Where D is the diameter of the tube; h2 is the length of the tube; σ p is the platform stress of the foam; k and n are the material constants of the foam; ε D is the densification strain of the foam; where k, n and ε D Determined according to the stress-strain curve of the foam, the function of the foam stress-strain curve is:

[0129]

[0130] Where ε is the strain of the foam; σ f is the stress of the foam at strain ε;

[0131] Further preferably, in the process of ship collision anti-collision device, the influence of strain rate on foam is considered, and the formula considering the strain rate effect of foam is: Among them, σ p (ε) is the nonlinear expression of foam stress-strain after considering the impact effect; σ(ε) is the nonlinear expression of foam stress-strain under quasi-static action; ε is the strain of the foam; is the strain rate of the quasi-static uniaxial test; is the reference strain rate under ship impact, preferably, The value ranges from 0.01 to 10 seconds. -1 ; a and b are the strain rate parameters of the foam, preferably, a=0.0430, b=0.0165.

[0132] S2A4, according to the resistance F of a single empty round tube in the inner core structure tubeand the resistance F of the foam in a single tube foam Sum and obtain the resistance F of a single foam-filled circular tube in the inner core structure i , where F i =F tube +F foam ;

[0133] S2A5, based on the resistance F of a single foam-filled circular tube i and impact depth δ n The number of single-layer circular tubes participating in the deformation n0 is used to calculate the overall resistance F of the inner core structure. t , where F t =n0F i ;

[0134] Preferably, in step S2, the resistance F of the outer steel plate is calculated punch :

[0135] S2B1. Calculate the critical impact depth Δ0 before the outer steel plate breaks and fails:

[0136]

[0137] Wherein, l0 is the length of the outer steel plate before collision; ε0 is the critical strain of the outer steel plate steel, preferably, ε0 ​​is 0.05 to 0.1;

[0138] S2B2, according to the critical impact depth Δ0 and impact depth δ n Calculate the resistance F of the outer steel plate punch , the calculation steps are:

[0139]

[0140] Where h1 is the height of the anti-collision device; σ y3 is the yield stress of the outer steel plate; t punch is the thickness of the outer steel plate; C is the length of the top steel plate and the bottom steel plate; n2 is the impact depth δ n The number of cracks after the lower steel plate breaks, n2 is 2 to 4; θ1 is half of the expansion angle of the ship; l is the collision depth δ n The length of the lower crack, where l = δ n / tanθ1; μ is the friction coefficient between the outer steel plate and the ship, preferably, μ is 0.15 to 0.3;

[0141] Preferably, in step S2, the resistance F of the top steel plate is calculated fold1 :

[0142]

[0143] Among them, π is the ratio of circumference to diameter; σ is the ratio of circumference to diameter. y1is the yield stress of the top steel plate; t f1 is the thickness of the top steel plate, C is the length of the top steel plate and the bottom steel plate; H1 is the folding wavelength of the top steel plate after collision;

[0144] Further preferably, the calculation formula of the folding wavelength H1 after the top steel plate hits is:

[0145]

[0146] Preferably, in step S2, the resistance F of the bottom steel plate is calculated fold2 :

[0147]

[0148] Among them, σ y2 is the yield stress of the bottom steel plate; t f2 is the thickness of the bottom steel plate; C is the length of the top and bottom steel plates; H2 is the folding wavelength of the bottom steel plate after collision.

[0149] Further preferably, the calculation formula of the folding wavelength H2 after the bottom steel plate hits is:

[0150]

[0151] S3, will hit the depth δ n Resistance F of the lower top steel plate fold1 , resistance F of bottom steel plate fold2 , the overall resistance of the inner core structure F t And the resistance of the outer steel plate F punch Sum and determine the impact depth δ n Total resistance of the lower anti-collision device P f , where P f =F t +F fold1 +F fold2 +F punch ;

[0152] S4. Determine the impact depth δ n Is it greater than or equal to the total deformable width L of the anti-collision device? If not, the collision depth δ n Iterate, and then repeat steps S2, S3 and S4; if so, then according to all the collision depths δ n And the impact depth δ n The total resistance P of the corresponding anti-collision device f The resistance-impact depth curve P of the anti-collision device f (δ n );

[0153] S5. According to the anti-collision device's resistance-impact depth curve P f (δ n) is integrated to obtain the energy-impact depth curve E of the anti-collision device f (δ n ),in

[0154] By means of the crash resistance analysis method of the steel and UHPC combined crash protection device of the present invention, the crash resistance of the steel and UHPC combined crash protection device can be analyzed by simultaneously considering the resistance-impact depth relationship of the inner core structure, the top steel plate, the bottom steel plate and the outer steel plate; compared with the traditional method of performing analysis based on a refined finite element model, this method can quickly provide crash resistance analysis for the proposed steel-UHPC combined crash protection device while providing a certain accuracy, help technicians determine whether it is necessary to optimize the size of the proposed combined crash protection device, save a lot of calculation cost and time, and is suitable for actual engineering needs.

[0155] Example 2

[0156] An optimization design method for a steel and UHPC combined anti-collision device comprises the following steps:

[0157] SO1: Determine the resistance-impact depth curve and energy-impact depth curve of the proposed steel and UHPC combined anti-collision device according to the anti-collision device crash resistance analysis method described in Example 1, and then determine the energy-local peak collision force curve of the anti-collision device according to the resistance-impact depth curve and energy-impact depth curve of the anti-collision device;

[0158] In this embodiment, a steel and UHPC combined anti-collision device is designed based on the pier survey. Figure 6 After the proposed design of the steel and UHPC combined anti-collision device, various parameters of the proposed steel and UHPC combined anti-collision device can be obtained, such as the thickness t of the outer steel plate. punch , the thickness of the top steel plate t f1 , the thickness of the bottom steel plate t f2 , the thickness of the circular tube in the inner core structure t t , the length l0 of the outer steel plate before being hit, the length h2 of the round tube, the diameter D of the round tube, the radius R of the round tube in the inner core structure and the deformable total width L of the anti-collision device, etc. Through these parameters, the anti-collision performance of the steel and UHPC combined anti-collision device of the proposed design can be analyzed according to the anti-collision analysis method of the steel and UHPC combined anti-collision device in Example 1, and the resistance-impact depth curve of the anti-collision device can be obtained, and the energy-impact depth curve of the anti-collision device can be obtained according to the integration of the resistance-impact depth curve of the anti-collision device, and the energy-impact depth curve of the anti-collision device can be eliminated by eliminating the intermediate variable (impact depth) through the resistance-impact depth curve and the energy-impact depth curve of the anti-collision device.

[0159] Next, according to the navigation conditions required by the defense, determine the type of navigable ships and the maximum displacement tonnage mv , navigation speed v0 and additional mass coefficient C m Based on these parameters, the total initial energy E0 required for defense is calculated as:

[0160]

[0161] Preferably, C m The value ranges from 0.1 to 0.3;

[0162] During the ship collision process, the initial total kinetic energy E0 is absorbed by the ship, bridge piers and anti-collision devices. From the perspective of the law of conservation of energy, the energy relationship in the collision system is: E0 = E f +E v +E s ;

[0163] Among them, E f is the energy absorbed by the anti-collision device, E v is the energy absorbed by the ship, E s The energy absorbed by the bridge pier.

[0164] Determine the configuration of the ship according to the type of navigable ships, and then determine the resistance-impact depth curve of the ship according to the configuration of the ship. Preferably, the resistance-impact depth curve of the ship is determined by a refined finite element model; determine the energy-impact depth curve of the ship according to the resistance-impact depth curve of the ship, and then determine the energy-local peak collision force curve of the ship by eliminating the intermediate variable (i.e., collision depth) according to the resistance-impact depth curve and the energy-impact depth curve of the ship. Determine the resistance-impact depth curve of the pier according to the pier structure. Preferably, the resistance-impact depth curve of the pier is determined by a refined finite element model; determine the energy-impact depth curve of the pier according to the resistance-impact depth curve of the pier, and then determine the energy-local peak collision force curve of the pier according to the resistance-impact depth curve and the energy-impact depth curve of the pier by eliminating the intermediate variable (i.e., collision depth); wherein, according to the energy relationship in the collision system, the following is obtained:

[0165]

[0166] in, The anti-collision device resistance-impact depth curve is from O to the maximum impact depth a of the anti-collision device. f The integral of The ship resistance-impact depth curve is from O to ship impact depth a v The integral of is the pier resistance-impact depth curve from O to the pier displacement a s Preferably, in the process of optimizing the design of the anti-collision device, as a conservative consideration, the energy absorbed by the pier is ignored, and the initial total kinetic energy of the ship is absorbed by the ship and the anti-collision device.

[0167] When the energy absorbed by the bridge pier is not considered, the total energy-local peak collision force curve is determined by the energy-local peak collision force curve of the anti-collision device and the energy-local peak collision force curve of the ship, such as Figure 6 As shown;

[0168] When the energy absorbed by the bridge pier is considered, the total energy-local peak collision force curve is determined by the energy-local peak collision force curve of the anti-collision device, the energy-local peak collision force curve of the ship and the energy-local peak collision force curve of the bridge pier;

[0169] S02: Figure 6 As shown, the initial total energy E0 to be protected is substituted into the total energy-local peak collision force curve to determine the local peak collision force P when the initial total energy is absorbed. t According to the local peak collision force P t Calculate the energy E that the anti-collision device needs to absorb f ; Then the anti-collision device energy-impact depth curve and the energy E that the anti-collision device needs to absorb are f , determine the maximum collision depth a of the anti-collision device f ;

[0170] S03: Figure 6 As shown, the local peak collision force P t and the maximum collision depth of the anti-collision device a f Whether it meets the requirements: If the local peak collision force P t and the maximum collision depth of the anti-collision device a f If both meet the requirements, the anti-collision device design is completed; if the local peak collision force P t and the maximum collision depth of the anti-collision device a f If at least one of the above does not meet the requirements, the anti-collision device needs to be optimized. After optimization, the total energy-local peak collision force curve in step SO1 is updated, and steps S02-S03 are repeated until the local peak collision force P t and the maximum collision depth of the anti-collision device a f All requirements are met and the optimization design of the anti-collision device is completed;

[0171] Among them: Figure 6 As shown, the local peak collision force P t The way to meet the requirements is to set the local peak collision force P t The collision force P between the ship and the bridge pier without considering the anti-collision device v-b For comparison, if P is satisfied t ≤(1-λ p )×P v-b , it means that the proposed anti-collision device meets the requirements for reducing the ship collision force, where λ p is the ship impact force reduction rate that needs to be met, preferably, λp Take 0.1~0.3;

[0172] Among them, the collision force between ship and bridge pier is P v-b It can be determined by establishing a refined numerical simulation model of ship-bridge collision; as a preferred method, the collision force P between the ship and the bridge pier under the anti-collision device is not considered. v-b The calculation formula is:

[0173] P v-b = zηβv0[(1+C M )m v ] 0.62 ;

[0174] Among them, z is the ship collision force coefficient, preferably, z takes a value of 0.033; η is the correction coefficient of geometric size, preferably, η takes a value of 1.O; β is the correction coefficient of impact angle, preferably, β takes a value of 1.O.

[0175] like Figure 6 As shown, the maximum collision depth a of the anti-collision device is determined f The way to meet the demand is: the maximum collision depth of the anti-collision device is a f Compared with the total deformable width L of the proposed anti-collision device, if a is satisfied f ≤λ a ×L, it means that the proposed anti-collision device meets the requirements for reducing the ship collision force, where λ a The maximum deformation rate allowed by the anti-collision device is preferably, preferably, λ a Take 0.7~0.9.

[0176] The optimization design method of the steel and UHPC combined anti-collision device of the present invention gradually optimizes the design parameters by combining the energy conservation theory of ships, bridge piers and anti-collision devices. This method can accurately predict the peak collision force and the collision depth of the anti-collision device according to the ship speed and the ship displacement tonnage, and ensure that the anti-collision device meets the requirements in terms of ship collision force reduction and deformation control through multiple verifications. Compared with the traditional optimization process that relies on refined numerical models, this method is faster and more convenient, avoiding the time and cost consumption caused by frequent modeling, calculation and adjustment in traditional methods, and significantly improving the design efficiency.

[0177] Application examples:

[0178] The piers of a certain cross-river bridge are located in the main channel area. The risk of the piers being hit by ships is relatively high. Therefore, it is necessary to design a combined anti-collision device of steel and UHPC that can absorb the impact energy and protect the integrity of the pier structure.

[0179] In this application case, based on the specific structural dimensions of a steel and UHPC combined anti-collision device, the above-mentioned anti-collision analysis method of a steel and UHPC combined anti-collision device is first used to perform anti-collision analysis, as follows:

[0180] Step O1: Determine the maximum displacement tonnage of the ship based on the channel grade and navigation flow analysis v =2750t, maximum navigation speed v0 = 4m / s, the additional mass factor to be considered is C m =O.1;

[0181] Step 02: According to the steel and UHPC combined anti-collision device proposed for the cross-river bridge, obtain relevant parameters. The height of the proposed anti-collision device is h1 = 3.Om, the total deformable width L is 2.0m, the thickness of the outer steel plate, the top steel plate and the bottom steel plate are all 10mm, and the yield stress σ y1 =σ y2 =σ y3 =σ y0 =295MPa, plastic strain hardening modulus E P =1600MPa, foam platform stress σ p =0.18MPa, densification strain ε D =0.2, material parameters k=2.28MPa, n=3.79, D of the vertical circular tube in the inner core structure=1.0m, according to the ship-anti-collision device collision relationship, the number of single layers of vertical circular tubes involved in deformation energy absorption n0=4, and the number of layers n1=2;

[0182] Step 03: According to Figure 3 As shown in the crash resistance analysis process, assuming that the impact depth change Δδ = 0.01, the overall resistance-impact depth relationship of the inner core structure in the steel and UHPC combined crash resistance device is calculated according to steps S2-S4, where the foam resistance-impact depth curve is as follows: Figure 7 As shown in (a), the resistance-impact depth curve of the vertical circular tube is as follows Figure 7 (b)

[0183] Step 04: According to Figure 3 The crash resistance analysis process shown in FIG. 1 calculates the resistance-impact depth relationship of the top (bottom) steel plate in the steel and UHPC combined crash resistance device according to steps S2-S4, as shown in FIG. Figure 7 As shown in (c), since the thickness of the top steel plate and the bottom steel plate are the same, the calculation results are the same, and only one of them can be calculated;

[0184] Step 05: According to Figure 3 As shown in the crashworthiness analysis process, assuming that the crash depth change Δδ = 0.01, the resistance-crash depth relationship of the outer steel plate in the steel and UHPC combined crashworthiness device is calculated according to steps S2-S4, as shown in Figure 7 (d)

[0185] Step 06: Execute the process of step S4 to finally obtain the resistance-impact depth curve of the steel and UHPC combined anti-collision device, such as Figure 8 As shown in (a), the energy-impact depth curve of the steel and UHPC combined anti-collision device can be determined as follows: Figure 8 (b);

[0186] Figure 8 (a) is a comparison of the resistance-impact depth curve obtained by the refined finite element model and the crashworthiness analysis method of a steel and UHPC combined crashworthiness device according to an embodiment of the present invention, Figure 8 (b) is a comparison of the energy-impact depth curve obtained by the refined finite element model and the crashworthiness analysis method of a steel and UHPC combined crashworthiness device according to an embodiment of the present invention. The results show that the crashworthiness analysis method of a steel and UHPC combined crashworthiness device proposed in the present invention can predict the crashworthiness of the combined crashworthiness device with high accuracy;

[0187] Next, the anti-collision device is optimized using the above-mentioned optimization design method for the combination of steel and UHPC. The specific process is as follows:

[0188] Step 07: According to the above-mentioned crash resistance analysis method of a steel and UHPC combined crash resistance device, the crash resistance of the proposed combined crash resistance device is determined, such as Fig. 9 As shown on the right;

[0189] Step 08: Displacement tonnage of typical ships in the navigable basin m v =2750t, the maximum speed of the ship v0 = 4m / s, and the additional mass coefficient C m =O.1, therefore, according to the formula, the maximum initial total energy of the defense can be calculated as E0=24.2MJ;

[0190] Step 09: By establishing a refined finite element model of the ship, the ship's resistance-collision depth curve is obtained. Fig. 9 As shown on the left;

[0191] Step 10: Convert the ship's resistance-impact depth curve and the anti-collision device's resistance-impact depth curve into an energy-impact depth curve, and establish the following: Figure 1 The peak force-energy relationship curve shown in Figure O shows that the left side shows the energy-impact depth relationship curve of the ship and the anti-collision device, and the right side shows the relationship between the peak force and energy consumption of the ship and the anti-collision device;

[0192] Step 11: Substitute the maximum initial total energy E0 = 24.2 MJ into Figure 1 O on the right, it can be determined that when the absorbed energy is 24.2MJ, P t =16.97MN, the energy absorbed by the ship is Ev =11.21MJ, the energy absorbed by the anti-collision device is E f =12.99MJ;

[0193] Step 13: According to the energy E absorbed by the ship v =11.21MJ, substitute Figure 1 The collision depth of the ship can be determined on the left side of O v =1.21m, according to the energy E absorbed by the anti-collision device f =1299MJ, substitute Figure 1 O on the left side can determine the impact depth of the anti-collision device a f =1.68m;

[0194] Step 14: According to the formula, the collision force P between the ship and the bridge pier without considering the anti-collision device can be determined. v-b =18.99MN, so (1-λ p )×P v-b =0.75×18.99=14.24MN, λ a ×L=0.8×2=1.6m. The proposed steel and UHPC combined anti-collision device P t =16.97MN, greater than (1-λ p )×P v-b =14.24MN, the ship impact force reduction rate does not meet the requirements; a f =1.68m, greater than λ a ×L=1.6m, the deformation degree of the anti-collision device does not meet the requirements. Therefore, an optimized design is required;

[0195] Step 15: Without changing the configuration of the steel and UHPC combined anti-collision device, the steel plate thickness is designed to be 12 mm, and steps 07-13 are repeated to obtain the collision response of the steel and UHPC combined anti-collision device with increased steel plate thickness. Fig.11 As shown. By calculation, it can be concluded that P t =16.97MN, greater than (1-λ p )×P v-b =14.24MN; a f =1.56m, which is less than λ a ×L=1.6m. It can be seen from the comparison that the proposed steel and UHPC combined anti-collision device does not meet the technical requirements;

[0196] Step 16: Change the number of layers of the inner core structure in the steel and UHPC combined anti-collision device to 3 layers (n1=3, L=3.0m), and design the steel plate thickness to 10mm. Repeat steps 07-12 to obtain the collision response of the steel and UHPC combined anti-collision device with an increased number of inner core structure layers. Fig.12 As shown. By calculation, it can be concluded that Pt =12.91MN, which is less than (1-λ p )×P v-b =14.24MN; a f =2.36m, which is less than λ a ×L=2.4m. By comparison, it can be seen that the proposed design of the steel and UHPC combined anti-collision device meets the technical requirements.

[0197] Table 1 is a comparison of the calculation time and required disk space between the method proposed in the present invention and the refined finite element model.

[0198] Table 1 Comparison of computation time and required disk space

[0199] Working conditions Calculation time (seconds) Required disk space (KB) <![CDATA[Refined finite element model (n1 = 2)]]> 57060 11.0×109 <![CDATA[The method proposed by the present invention (n1 = 2)]]> 2 1.6×106 <![CDATA[Refined finite element model (n1 = 3)]]> 100560 12.7×109 <![CDATA[The method proposed by the present invention (n1 = 3)]]> 3 1.8×106

[0200] As can be seen from Table 1, the computational efficiency of the crashworthiness analysis and optimization design method for a steel and UHPC combined crashproof device proposed in the present invention is significantly better than that of the traditional refined finite element model. Specifically, the method can obtain crashworthiness results in a shorter time, the calculation speed is increased by several times, and the design cycle is significantly shortened. In contrast, the refined finite element model requires a large amount of computing resources, and each analysis requires dozens of hours or even longer computing time. In terms of storage, the disk space required by the method of the present invention is also much smaller than that of the refined finite element model, avoiding the need for high-performance computing resources and large-capacity storage devices, and reducing the hardware investment cost of the project. Therefore, the method of the present invention has good engineering applicability, can quickly respond to changes in requirements in the design stage, effectively improves the design and optimization efficiency, and is particularly suitable for rapid pre-evaluation and optimization adjustment in actual engineering.

[0201] In summary, the present invention provides a collision resistance analysis method for a steel and UHPC combined collision avoidance device, which can quickly predict the collision resistance performance of the collision avoidance device, make up for the deficiencies of the prior art, and significantly improve the design efficiency of the collision avoidance device; at the same time, the present invention also provides an optimization design method for a steel and UHPC combined collision avoidance device, which can quickly predict various collision responses during a ship collision process, and accurately determine whether the design requirements are met, thereby effectively improving the optimization efficiency of the collision avoidance device.

[0202] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for analyzing the crashworthiness of a steel and UHPC combined crashproof device, characterized in that: The following steps are involved: S1. Determine the structural dimension parameters of the steel and UHPC combined anti-collision device in the proposed design; The steel and UHPC combined anti-collision device comprises: a UHPC panel, a box body and an inner core structure, the box body comprises a top steel plate, a bottom steel plate, an inner steel plate and an outer steel plate, the top steel plate is connected to the top of the inner steel plate and the outer steel plate, the bottom steel plate is connected to the bottom of the inner steel plate and the outer steel plate, the UHPC panel is connected to the outer side of the outer steel plate and the inner steel plate, and the inner core structure is arranged in the box body; when a ship collides with the anti-collision device, the UHPC panel can drive the outer steel plate, the top steel plate, the bottom steel plate and the inner core structure to participate in deformation to absorb the initial kinetic energy of the ship; S2. Calculate the collision depth δ according to the structural dimensions of the proposed steel and UHPC combined anti-collision device. n Resistance F of the lower top steel plate fold1 , resistance F of bottom steel plate fold2 , the overall resistance of the inner core structure F t And the resistance of the outer steel plate F punch ; S3, will hit the depth δ n Resistance F of the lower top steel plate fold1 , resistance F of bottom steel plate fold2 , the overall resistance of the inner core structure F t And the resistance of the outer steel plate F punch Sum and determine the impact depth δ n Total resistance of the lower anti-collision device P f , where P f =F t +F fold1 +F fold2 +F punch ; S4. Determine the impact depth δ n Is it greater than or equal to the total deformable width L of the anti-collision device? If not, the collision depth δ n Iterate, and then repeat steps S2, S3 and S4; if so, then according to all the collision depths δ n And the impact depth δ n The total resistance P of the corresponding anti-collision device f The resistance-impact depth curve P of the anti-collision device f (δ n ); S5. According to the anti-collision device's resistance-impact depth curve P f (δ n ) is integrated to obtain the energy-impact depth curve E of the anti-collision device f (δ n ),in 2. The crash resistance analysis method of a steel and UHPC combined crash protection device according to claim 1, characterized in that: The inner core structure uses vertical circular tubes filled with foam arranged in layers. When the ship hits, the number of single-layer circular tubes that participate in the deformation is n0, and the number of layers is n1; The overall resistance F of the inner core structure in step S2 t The calculation process is as follows: S2A1, according to the impact depth δ n Determine the impact depth δ of a single tube t , the impact depth of a single circular tube δ t =δ n / n1; S2A2, according to the impact depth δ of a single round tube t , the structural dimensions and material properties of the anti-collision device are used to calculate the resistance F of a single hollow circular tube in the inner core structure. tube ; S2A3, according to the impact depth δ of a single round tube t , the structural dimensions and material properties of the anti-collision device are used to calculate the resistance F of the foam in a single circular tube in the inner core structure. foam ; S2A4, according to the resistance F of a single empty round tube in the inner core structure tube and the resistance F of the foam in a single tube foam Sum and obtain the resistance F of a single foam-filled circular tube in the inner core structure i , where F i =F tube +F foam ; S2A5, based on the resistance F of a single foam-filled circular tube i and impact depth δ n The number of single-layer circular tubes participating in the deformation n0 is used to calculate the overall resistance F of the inner core structure. t , where F t =n0F i .

3. The crash resistance analysis method of a steel and UHPC combined crash protection device according to claim 1, characterized in that: The resistance F of the outer steel plate in step S2 punch The calculation process is as follows: S2B1. Calculate the critical impact depth Δ0 before the outer steel plate breaks and fails: Among them, l0 is the length of the outer steel plate before impact; ε0 is the critical strain of the outer steel plate steel; S2B2, according to the critical impact depth Δ0 and impact depth δ n Calculate the resistance F of the outer steel plate punch , the calculation steps are: Where h1 is the height of the anti-collision device; σ y3 is the yield stress of the outer steel plate; t punch is the thickness of the outer steel plate; C is the length of the top steel plate and the bottom steel plate; n2 is the impact depth δ n The number of cracks after the lower steel plate breaks, n2 is 2 to 4; l is the impact depth δ n The length of the lower crack, l = δ n / tanθ1; θ1 is half of the expansion angle of the ship; μ is the friction coefficient between the outer steel plate and the ship, and μ takes a value of 0.15~0.

3.

4. The crash resistance analysis method of a steel and UHPC combined crash protection device according to claim 1, characterized in that: The resistance F of the top steel plate in step S2 fold1 The calculation process is as follows: Among them, π is the ratio of circumference to diameter; σ is the ratio of circumference to diameter. y1 is the yield stress of the top steel plate; t f1 is the thickness of the top steel plate, C is the length of the top steel plate and the bottom steel plate; H1 is the folding wavelength of the top steel plate after collision; The resistance F of the bottom steel plate in step S2 fold2 The calculation process is as follows: Among them, σ y2 is the yield stress of the bottom steel plate; t f2 is the thickness of the bottom steel plate; C is the length of the top and bottom steel plates; H2 is the folding wavelength of the bottom steel plate after collision.

5. The crash resistance analysis method of a steel and UHPC combined crash protection device according to claim 2, characterized in that: The resistance F of the single empty round tube in step S2A2 tube The calculation process is as follows: A2.

1. Calculation of the effective yield stress σ of the circular tube in the inner core structure y ,in σ y0 is the yield stress of the circular tube; A2.

2. Calculate the initial resistance F of a single empty circular tube in the inner core structure tube，0 : Where R is the radius of the circular tube in the inner core structure; k t is the vertical constraint coefficient of the tube group structure; M0 is the full plastic bending moment in the lateral crushing of the circular tube, where t t is the thickness of the tube; h2 is the length of the tube; A2.

3. Calculate the resistance F of a single hollow circular tube in the inner core structure tube : Among them, cos is the cosine function; sin is the sine function; γ is the angle between the tangent line and the vertical line at the intersection of the hardened section and the rigid section in the transverse crushing of the circular tube. The calculation method of γ is: First, assume that λ = F tube / F tube，0 and q 2 =ζ 2 F tube / 2E P I, combined with the resistance F of a single hollow tube in the inner core structure tube The calculation formula and the initial resistance F of the inner core structure empty circular tube tube，0 The calculation formula can be obtained: Among them, λ, q, ζ and m are the deformation coefficients of the hardened section of the round tube after considering the mutual constraints of multiple round tubes; E P is the plastic hardening modulus of the circular tube; I is the moment of inertia of the circular tube; Then, substitute λ and m into the calculation formula of the angle γ between the tangent line and the vertical line at the intersection of the hardened section and the rigid section in the transverse crushing of the circular tube to obtain the angle γ. The calculation formula of the angle γ between the tangent line and the vertical line at the intersection of the hardened section and the rigid section in the transverse crushing of the circular tube is: Among them, θ is the angle operation parameter; The resistance F of the foam in the single empty tube in step S2A3 foam The calculation formula is as follows: Where D is the diameter of the tube; h2 is the length of the tube; σ p is the platform stress of the foam; k and n are the material constants of the foam; ε D is the densification strain of the foam; where k, n and ε D Determined according to the stress-strain curve of the foam, the function of the foam stress-strain curve is: Where ε is the strain of the foam; σ f is the stress of the foam at strain ε.

6. The crash resistance analysis method of a steel and UHPC combined crash protection device according to claim 4, characterized in that: The calculation formula of the folding wavelength H1 after the top steel plate hits is: The calculation formula of the folding wavelength H2 after the bottom steel plate hits is:

7. The crash resistance analysis method of a steel and UHPC combined crash protection device according to claim 5, characterized in that: When the ship hits the anti-collision device, considering the influence of strain rate on the round tube steel, the yield stress σ y0 The calculation formula is: in, is the reference strain rate under ship impact; P and X are the strain rate parameters of round tube steel; σ′ y0 is the yield strength of round tube steel in quasi-static uniaxial test.

8. The crash resistance analysis method of a steel and UHPC combined crash protection device according to claim 5, characterized in that: When a ship hits an anti-collision device, the effect of strain rate on foam is considered. The formula considering the strain rate effect of foam is: Among them, σ p (ε) is the nonlinear expression of foam stress-strain after considering the impact effect; σ(ε) is the nonlinear expression of foam stress-strain under quasi-static action; ε is the strain of the foam; is the strain rate of the quasi-static uniaxial test; is the reference strain rate for simulating the anti-collision device under the impact of a ship; a and b are the strain rate parameters of the foam.

9. An optimization design method for a steel and UHPC combined anti-collision device, characterized in that: The following steps are involved: S01: According to the crash resistance analysis method of the steel and UHPC combined crash protection device according to any one of claims 1 to 8, firstly determine the resistance-crash depth curve and energy-crash depth curve of the steel and UHPC combined crash protection device to be designed, and further derive the energy-local peak crash force curve of the crash protection device based on the two curves; At the same time, according to the navigation conditions required by the defense, the maximum displacement tonnage of navigable ships is determined. v , navigation speed v0 and additional mass coefficient C m Based on these parameters, the total initial energy E0 required for defense is calculated as: At the same time, the ship's configuration is determined according to the ship type, and the ship's resistance-impact depth curve is obtained from it, and then the ship's energy-impact depth curve is derived; the ship's energy-local peak collision force curve is determined through the ship's resistance-impact depth curve and energy-impact depth curve; When the energy absorbed by the bridge pier is not considered, the total energy-local peak collision force curve can be derived by combining the energy-local peak collision force curve of the anti-collision device with the energy-local peak collision force curve of the ship; When considering the energy absorption of the bridge pier, it is necessary to first determine the resistance-impact depth curve of the bridge pier based on the structural characteristics of the bridge pier, and derive its energy-impact depth curve and energy-local peak impact force curve; then, by integrating the energy-local peak impact force curves of the anti-collision device, the ship and the bridge pier, the total energy-local peak impact force curve is determined; S02: Substitute the initial total energy E0 to be protected into the total energy-local peak collision force curve to determine the local peak collision force P when absorbing the initial total energy t , according to the local peak collision force P t Calculate the energy E that the anti-collision device needs to absorb f ; Then the anti-collision device energy-impact depth curve and the energy E that the anti-collision device needs to absorb are f , determine the maximum collision depth a of the anti-collision device f ; S03: Determine the local peak collision force P t and the maximum collision depth of the anti-collision device a f Whether it meets the requirements: If the local peak collision force P t and the maximum collision depth of the anti-collision device a f If both meet the requirements, the anti-collision device design is completed; if the local peak collision force P t and the maximum collision depth of the anti-collision device a f If at least one of the above does not meet the requirements, the anti-collision device needs to be optimized and designed. After optimization, the total energy-local peak collision force curve in step S01 is updated, and steps S02-S03 are repeated until the local peak collision force P t and the maximum collision depth of the anti-collision device a f All requirements are met and the optimization design of the anti-collision device is completed; Among them, the local peak collision force P is determined t The way to meet the requirements is to set the local peak collision force P t The collision force P between the ship and the bridge pier without considering the anti-collision device v-b For comparison, if P is satisfied t ≤(1-λ p )×P v-b , it means that the proposed anti-collision device meets the requirements for reducing the ship collision force; where λ p is the ship impact force reduction rate that needs to be met; Determine the maximum collision depth a of the anti-collision device f The way to meet the demand is: the maximum collision depth of the anti-collision device is a f Compared with the total deformable width L of the proposed anti-collision device, if a is satisfied f ≤λ a ×L, it means that the proposed anti-collision device meets the requirements for reducing the ship collision force; where λ a The maximum deformation rate allowed for the anti-collision device.

10. The optimization design method of a steel and UHPC combined anti-collision device according to claim 9, characterized in that: The collision force P between the ship and the bridge pier without considering the anti-collision device v-b The calculation formula is: P v-b =zηβv0[(1+C M )m v ] 0.62 ; Among them, z is the ship collision force coefficient; η is the correction factor of geometric dimensions; β is the correction factor of impact angle.

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