Anti-collision Performance Analysis and Optimization Design Method for a Composite Anti-collision Device of Steel and UHPC

Abstract

The present invention relates to a method for anti-collision performance analysis and optimization design of a steel and UHPC combined anti-collision device. The anti-collision performance analysis method simultaneously considers the resistance-penetration depth relationship of the inner core structure, the top steel plate, the bottom steel plate, and the outer steel plate. Its calculation method is scientific, and the calculation results are safe and reliable. Compared with the traditional method that relies on refined finite element models, this method can quickly judge the anti-collision performance of the anti-collision device, saving a large amount of calculation costs and time, and is applicable to the actual engineering requirements. The optimization design method combines the relationship between the ship resistance-penetration depth and the anti-collision device resistance-penetration depth, or combines the relationship between the ship resistance-penetration depth, the anti-collision device resistance-penetration depth, and the pier resistance-penetration depth, and can accurately predict the peak collision force and the maximum penetration depth of the anti-collision device according to the ship speed and the ship displacement tonnage. This method can quickly adjust and optimize the design scheme of the anti-collision device in the preliminary design stage, realizing efficient and accurate design.

Description

Technical Field

[0001] The present invention relates to the technical field of analysis and design of steel and UHPC composite anti-collision devices, and particularly relates to a method for analyzing the anti-collision performance and optimizing the design of a steel and UHPC composite anti-collision device. Background Art

[0002] With the rapid development of social economy, bridges are playing an increasingly important role in transportation. As an important part of infrastructure, the safety of bridges is directly related to the smoothness of transportation and the safety of people's lives and property. However, bridges face many potential safety hazards during their service life, especially the threats to bridge structures caused by factors such as traffic accidents and natural disasters. Among them, in recent years, serious ship collision accidents have occurred frequently, seriously affecting traffic safety and the long-term use of bridges, resulting in a large number of casualties, bridge collapses, economic losses and extensive social impacts.

[0003] To effectively prevent the damage caused by ship collisions to bridges, traditional bridge anti-collision devices usually adopt steel structure designs. Steel structure anti-collision devices have high strength and good plastic deformation ability, and can effectively absorb energy and relieve the transmission of collision forces during the impact process, thus playing a role in protecting bridges. However, steel structure anti-collision devices also have some defects. For example, their durability is poor, and their performance is prone to decline due to environmental corrosion, thus increasing the maintenance cost and replacement frequency.

[0004] In this context, ultra-high performance concrete (UHPC), as a new type of material, has gradually been applied in bridge construction and anti-collision design due to its excellent mechanical properties, durability and anti-wear ability. Therefore, researchers have proposed the idea of combining steel with UHPC to form a steel and UHPC composite anti-collision device. And the research results show that during the process of ship impact, 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 improving the energy dissipation effect of the anti-collision device. This combined device makes full use of the respective advantages of steel and UHPC, and improves the overall protection performance of the anti-collision device.

[0005] However, at present, the impact resistance evaluation and design of steel and UHPC composite anti-collision devices mainly rely on the engineering experience of researchers. Traditional design methods often require repeated optimization and adjustment through physical experiments or high-precision finite element simulations. Each optimization requires re-establishing a refined finite element model of the ship-bridge-anti-collision device and conducting a large number of calculations. Since the number of grids in the entire collision model may reach millions, each analysis requires the use of a supercomputer for dozens of hours of solution, which greatly limits the efficiency of design and optimization. In addition, no relevant design methods are provided in the publicly available technologies, resulting in a cumbersome and inefficient overall design process for steel and UHPC composite anti-collision devices, greatly restricting their application.

[0006] In summary, there is an urgent need for a new method for analyzing and designing the impact resistance of steel-UHPC composite anti-collision devices, which can quickly predict the impact resistance performance of anti-collision devices and provide an efficient optimization design scheme, thereby solving the deficiencies in the prior art and improving the design efficiency of anti-collision devices. Summary of the Invention

[0007] The object of the present invention is to provide a method for analyzing and optimizing the impact resistance of a steel-UHPC composite anti-collision device, aiming to solve the deficiency of the current lack of an efficient design method, overcome the fact that the impact resistance evaluation and design of steel and UHPC composite anti-collision devices mainly rely on the engineering experience of researchers and rely on physical experiments or high-precision finite element simulations for repeated optimization and adjustment, and improve the design rationality and efficiency of steel-UHPC composite anti-collision devices. The specific technical solutions are as follows:

[0008] In the first aspect, the present invention provides a method for analyzing the impact resistance of a steel and UHPC composite anti-collision device, including the following steps:

[0009] S1. Determine the structural dimension parameters of the steel and UHPC composite anti-collision device in the proposed design; the steel and UHPC composite anti-collision device includes: a UHPC panel, a box body, and an inner core structure. The box body includes 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 tops of the inner steel plate and the outer steel plate, the bottom steel plate is connected to the bottoms of the inner steel plate and the outer steel plate, the UHPC panel is connected to the outside of the outer steel plate and the inner steel plate, and the inner core structure is arranged inside the box body; when a ship impacts 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 penetration depth δ according to the structural dimensions of the steel and UHPC composite anti-collision device in the proposed design n The resistance F of the lower top steel plate fold1 of the bottom steel plate fold2 the overall resistance F of the inner core structure t and the resistance F of the outer steel platepunch ;

[0011] S3. Determine the penetration depth δ n The resistance force F of the lower top steel plate fold1 , the resistance force F of the bottom steel plate fold2 , the overall resistance force F of the inner core structure t and the resistance force F of the outer steel plate punch are summed up to determine the penetration depth δ n The total resistance force P of the lower anti-collision device f , where P f = F t + F fold1 + F fold2 + F punch ;

[0012] S4. Judge whether the penetration depth δ n is greater than or equal to the deformable total width L of the anti-collision device; if not, iterate the penetration depth δ n , and then repeat steps S2, S3 and S4; if so, according to all penetration depths δ n and the penetration depth δ n corresponding to the total resistance force P of the anti-collision device f form the resistance force-penetration depth curve P of the anti-collision device f (δ n );

[0013] S5. Integrate according to the resistance force-penetration depth curve P of the anti-collision device f (δ n ) to obtain the energy-penetration depth curve E of the anti-collision device f (δ n ), where

[0014] The present invention provides an anti-collision performance analysis method for a steel and UHPC combined anti-collision device, which simultaneously considers the resistance force-penetration depth relationships of the inner core structure, the top steel plate, the bottom steel plate and the outer steel plate. Its calculation method is scientific, and the calculation results are safe and reliable. Compared with the traditional method relying on refined finite element models, this method can quickly judge the anti-collision performance of the anti-collision device, saving a large amount of calculation costs and time, and is applicable to the actual engineering requirements.

[0015] Preferably, in the above technical solution, the inner core structure adopts vertically arranged circular tubes filled with foam in a layered manner, and the number of single-layer circular tubes participating in deformation during ship impact is n0 and the number of layers is n1;

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

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

[0018] S2A2, according to the impact depth δ of a single 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 ;

[0019] S2A3, according to the impact depth δ of a single circular 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 hollow circular tube in the inner core structure tube and the resistance F of the foam in a single circular 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 involved in 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 hollow 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 fully plastic bending moment in the transverse 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 force F of a single empty circular tube in the inner core structure tube :

[0028]

[0029] where 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 hardening section and the rigid section in the transverse crushing of the circular tube, and the calculation method of γ is as follows:

[0030] First, assume that λ = F tube / F tube，0 and q 2 = ζ 2 F tube / 2E P I. Combining the calculation formula of the resistance force F of a single empty circular tube in the inner core structure tube and the calculation formula of the initial resistance force F tube，0 of the empty circular tube in the inner core structure, we can obtain: where λ, q, ζ, and m are all deformation coefficients of the hardening section of the circular tube considering the mutual restraint of multiple circular 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 hardening 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 hardening section and the rigid section in the transverse crushing of the circular tube is:

[0032]

[0033] where θ is the angle operation parameter;

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

[0035]

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

[0037]

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

[0039] Preferably, in the above technical solution, during the process of the ship impacting the anti-collision device, considering the influence of the strain rate on the circular tube steel, the yield stress σ of the circular tube y0 has the following calculation formula: where is the reference strain rate under ship impact; P and X are the strain rate parameters of the circular tube steel; σ′ y0 is the yield strength of the circular tube steel in a quasi-static uniaxial test.

[0040] Preferably, in the above technical solution, during the process of the ship impacting the anti-collision device, considering the influence of the strain rate on the foam, the formula considering the strain rate effect of the foam is: where σ p (ε) is the non-linear expression of the foam stress-strain considering the impact effect; σ(ε) is the non-linear expression of the 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 ship impact; a and b are the strain rate parameters of the foam.

[0041] The calculation method of the relationship between the internal core structure resistance and the impact depth fully considers the influence of the impact depth on the mutual restraint between the group of tubes. Taking the arrangement form of the steel tubes, the diameter and length of the circular tubes, and the strength of the steel and polyurethane as parameters, the relationship between the resistance and the impact depth that accurately reflects the mutual restraint effect of the group of tubes is obtained. This calculation method is scientific and rigorous, can better reflect the structural performance, and provides a reliable basis for the anti-collision performance analysis and optimization design of the anti-collision device.

[0042] Preferably, in the above technical solution, the resistance F of the outer steel plate described in step S2 punch is calculated as follows:

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

[0044]

[0045] where l0 is the length of the outer steel plate before being impacted; ε0 is the critical strain of the outer steel plate steel;

[0046] S2B2. According to the critical impact depth Δ0 and the impact depth δ n calculate the resistance F of the outer steel plate punch , and 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 collision depth δ n the number of cracks after the bottom steel plate fractures, n2 takes values from 2 to 4; l is the collision 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 values from 0.15 to 0.3.

[0049] Preferably in the above technical solution, the resistance F of the top steel plate described in step S2 fold1 is calculated as follows:

[0050]

[0051] where, π is the pi; σ 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 described in step S2 fold2 is calculated as follows:

[0053]

[0054] where, 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 steel plate and the bottom steel plate; H2 is the folding wavelength of the bottom steel plate after collision.

[0055] More preferably, the calculation formula for the folding wavelength H1 of the top steel plate after collision is:

[0056]

[0057] More preferably, the calculation formula for the folding wavelength H2 of the bottom steel plate after collision is:

[0058]

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

[0060] SO1: According to the anti-collision performance analysis method of the steel and UHPC combined anti-collision device, first determine the resistance-collision depth curve and energy-collision depth curve of the proposed steel and UHPC combined anti-collision device, and further derive the energy-local peak collision force curve of the anti-collision device based on these two curves;

[0061] Meanwhile, according to the navigation conditions required for flood prevention, determine the maximum displacement tonnage m of the navigable vessels v , the navigation speed v0, and the added mass coefficient C m . Based on these parameters, calculate the initial total energy E0 to be protected as follows:

[0062]

[0063] Meanwhile, determine the configuration of the vessel according to the vessel type, and thus obtain the resistance - penetration depth curve of the vessel, and then derive the energy - penetration depth curve of the vessel; through the resistance - penetration depth curve and the energy - penetration depth curve of the vessel, determine the energy - local peak collision force curve of the vessel;

[0064] When not considering the energy absorption of the pier, 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 vessel;

[0065] When considering the energy absorption of the pier, based on the structural characteristics of the pier, first determine the resistance - penetration depth curve of the pier, and derive its energy - penetration depth curve and energy - local peak collision force curve; then, by integrating the energy - local peak collision force curves of the anti - collision device, the vessel, and the pier, determine the total energy - local peak collision force curve;

[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 ; Subsequently, through the energy - penetration depth curve of the anti - collision device and the energy E that the anti - collision device needs to absorb f , determine the maximum penetration depth a of the anti - collision device f ;

[0067] S03: Judge whether the local peak collision force P t and the maximum penetration depth a of the anti - collision device f meet the requirements: If both the local peak collision force P t and the maximum penetration depth a of the anti - collision device f meet the requirements, the design of the anti - collision device is completed; if at least one of the local peak collision force P t and the maximum penetration depth a of the anti - collision device f does not meet the requirements, the anti - collision device needs to be optimized. After optimization, update the total energy - local peak collision force curve in step SO1, and then repeat steps S02 - S03 until both the local peak collision force P t and the maximum penetration depth a of the anti - collision device f meet the requirements, and the optimization design of the anti - collision device is completed;

[0068] Among them, the method for judging whether the local peak collision force P t meets the requirements is as follows: compare the local peak collision force P t with the collision force P v-b between the ship and the pier without considering the anti-collision device. If P t ≤(1 - λ p )×P v-b , it indicates that the designed anti-collision device meets the requirement of reducing the ship collision force; where δ n is the ship collision force reduction rate to be met.

[0069] The method for judging whether the maximum penetration depth a f of the anti-collision device meets the requirements is as follows: compare the maximum penetration depth a f of the anti-collision device with the total deformable width L of the designed anti-collision device. If a f ≤λ a ×L, it indicates that the designed anti-collision device meets the requirement of reducing the ship collision force; where λ a is the maximum allowable deformation rate of the anti-collision device.

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

[0071] Preferably, the calculation formula for the collision force P v-b between the ship and the pier without considering the anti-collision device 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 coefficient for geometric dimensions; β is the correction coefficient for the impact angle.

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

[0075] ​1. The present invention provides a method for analyzing the crashworthiness of a steel and UHPC composite anti-collision device, taking into account the resistance-penetration relationships of the inner core structure, top steel plate, bottom steel plate, and outer steel plate. Its calculation method is scientific, and the calculation results are safe and reliable. Compared with the traditional method that relies on refined finite element models, this method can quickly judge the crashworthiness of the anti-collision device, saving a large amount of calculation costs and time, and is applicable to the actual engineering requirements.

[0076] 2. The present invention provides a method for analyzing the crashworthiness of a steel and UHPC composite anti-collision device. The calculation method of the resistance-penetration relationship of the inner core structure fully considers the influence of the interaction between the penetration depth and the group of pipes. Taking the layout form of the circular pipes, the pipe diameter and length of the circular pipes, and the strength of the steel and polyurethane as parameters, the resistance-penetration relationship that accurately reflects the mutual restraint effect of the group of pipes is obtained. This calculation method is scientific and rigorous, can better reflect the structural performance, and provides a reliable basis for the crashworthiness analysis and optimal design of the anti-collision device.

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

[0078] In addition to the purposes, features, and advantages described above, the present invention has other purposes, features, and advantages. The following will refer to the drawings for a further detailed description of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] The drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic 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 is a schematic cross-sectional view of the internal structure of a steel and UHPC composite anti-collision device;

[0081] Figure 2 is a schematic view of a steel and UHPC composite anti-collision device under ship impact;

[0082] Figure 3 is a flowchart of the method for analyzing the crashworthiness of the steel and UHPC composite anti-collision device of the present invention;

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

[0084] Figure 5 It 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 for the steel and UHPC combined anti-collision device of the present invention;

[0086] Figure 7 It is a curve graph of the resistance - collision depth relationship of the energy dissipation component in the proposed steel and UHPC combined anti-collision device;

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

[0088] Figure 9 It is a curve graph of the resistance - collision depth relationship between the proposed steel and UHPC combined anti-collision device and the ship;

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

[0090] Figure 11 It is a schematic diagram of the collision response prediction of the steel and UHPC combined anti-collision device based on increasing the thickness of the steel plate;

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

[0092] Markings in the figure: 1, bridge pier; 2, ship; 100, UHPC panel; 110, inner core structure; 111, circular 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 implementation manners

[0093] The present invention will be further described in detail below in conjunction with specific embodiments. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments. All technologies implemented 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 expression terms indicating the orientation or positional relationship such as "upper", "lower", "left", "right", "center", "inner", "outer", etc. are all based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the invention product / device / equipment is commonly used. These terms of orientation or positional relationship are only for the convenience of describing the solution of the present invention or simplifying the description in the specific embodiments, so as to facilitate technicians to quickly understand the solution, rather than indicating or implying that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, it should not be construed as a limitation to the present invention.

[0095] In addition, if terms such as "horizontal", "vertical", "suspended", "parallel" appear, it does not mean that the corresponding device / component / element is required to be absolutely horizontal or vertical or suspended or parallel, but it can be slightly inclined or deviated. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and it does not mean that the structure must be completely horizontal, but it can be slightly inclined. Or, it can be simply understood that the corresponding device / component / element is arranged in the directions of "horizontal", "vertical", "suspended", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, more preferably within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still play its role in the solution of the present invention.

[0096] In addition, when expressions such as "first", "second", "third", etc. appear in the terms, they are only used to distinguish the description of the same or similar components, and should not be understood as emphasizing or implying the relative importance of a specific component.

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

[0098] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / limited, where terms such as "set", "installed", "connected", "connected", "provided with", "laid", "arranged" appear, they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be connection means commonly used in the art such as welding, riveting, bolting, threaded connection, etc. This connection can be a mechanical connection, an electrical connection or a communication connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two components.

[0099] Embodiment 1

[0100] This embodiment provides a method for analyzing the anti-collision performance of a steel and UHPC composite anti-collision device. Refer to Figure 1 and Figure 2 , the steel and UHPC composite 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 tops of the outer steel plate 131 and the inner steel plate 132. The bottom steel plate 122 is connected to the bottoms of the outer steel plate 131 and the inner steel plate 132. The inner core structure 110 is arranged inside the box body, and the UHPC panel 100 is connected to the outsides of the outer steel plate 131 and the inner steel plate 132.

[0101] Furthermore, as Figure 1 shown, a flange connecting plate 140 or the like may also be arranged inside the box body, dividing the anti-collision device into anti-ship-collision device units. The anti-ship-collision device units are also box-type structures, and multiple 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 arranged on the outside of the inner steel plate 132, and the inside of the fender 150 is the pier 1.

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

[0104] As Figure 2 shown, when the ship 2 hits the pier 1 out of control, the ship 2 will directly hit the UHPC panel 100 on the outside of the anti-collision device, and then mainly 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. Generally, the inner steel plate 132 does not participate in the deformation and energy absorption during the collision process. The UHPC panel 100 can prevent the anti-collision device from being punctured, effectively transfer the impact force to the internal energy-consuming structure, thereby reducing the impact force of the ship 2 on the pier 1; during the daily service process, the UHPC panel 100 can also prevent floating objects from scratching the internal steel plates.

[0105] To ensure the safe application of the steel and UHPC composite anti-collision device in bridge anti-collision, this embodiment provides a method for analyzing the anti-collision performance of the steel and UHPC composite anti-collision device. As Figure 3 shown, the method for analyzing the anti-collision performance of the steel and UHPC composite anti-collision device includes the following steps:

[0106] S1. Determine the structural dimension parameters of the steel and UHPC composite anti-collision device in the proposed design; as Figure 1 and Figure 2As shown, preferably, the inner core structure adopts vertically arranged circular tubes filled with foam. Further, the foam filling uses polyurethane foam. The diameter of the circular tube is D. During 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 deformable overall width is L = n1×D;

[0107] S2. Calculate the penetration depth δ according to the structural dimensions of the steel and UHPC combined anti-collision device formulated n Calculate the resistance F of the top steel plate as follows fold1 and the resistance F of the bottom steel plate fold2 and the overall resistance F of the inner core structure t and the resistance F of the outer steel plate punch ; among them, assuming the penetration depth δ n is the penetration depth of the anti-collision device, and also the penetration depth of the outer steel plate and the penetration depth of the inner core structure.

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

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

[0110] S2A2. Calculate the resistance F of a single empty circular tube in the inner core structure according to the impact depth δ of a single vertically arranged circular tube t , the structural dimensions and material properties of the anti-collision device tube ;

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

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

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

[0114] A2.2. Calculate the initial resistance force 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 restraint coefficient of the group tube structure. Preferably, k t takes a value of 0.05 - 0.1; M0 is the full plastic moment in the lateral crushing of the circular tube, where t t is the thickness of the circular tube; h2 is the length of the circular tube;

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

[0118]

[0119] where γ is the angle between the tangent line and the vertical line at the intersection of the hardening section and the rigid section in the lateral crushing of the circular tube, as shown in Figure 4 and Figure 5 ; cos is the cosine function; sin is the sine function;

[0120] As shown in Figure 4 , 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 composed of a rigid section AQ and a hardening section BQ will be formed during the deformation process, as shown in Figure 5 . The angle between the tangent line and the vertical line at the intersection of the rigid section AQ and the hardening section BQ is γ. The angle γ between the tangent line and the vertical line at the intersection of the hardening section and the rigid section in the lateral crushing of the circular tube can be obtained through finite element simulation or physical tests. For the convenience of calculating γ, further preferably, the calculation method of the angle γ between the tangent line and the vertical line at the intersection of the hardening section and the rigid section in the lateral crushing of the circular tube is:

[0121] First, assume that λ = F tube / F tube，0 and q 2 = ζ 2 F tube / 2E P I. Combining the resistance force F tube formula of a single empty circular tube in the inner core structure and the initial resistance force F tube，0 formula of a single empty circular tube, we can obtain: where λ, q, ζ, and m are all deformation coefficients of the hardening section of the circular tube considering the mutual restraint of multiple circular 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 hardening section and the rigid section in the lateral 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 hardening section and the rigid section in the lateral crushing of the circular tube is:

[0123]

[0124] where θ is the angle operation parameter.

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

[0126] Preferably, the resistance force F of the foam in the single empty circular tube described in step S2A3 foam has the following calculation formula:

[0127]

[0128] where D is the diameter of the circular tube; h2 is the length of the circular tube; σ p is the plateau 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 are determined according to the stress-strain curve of the foam. The function of the stress-strain curve of the foam is:

[0129]

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

[0131] Further preferably, during the process of the ship colliding with the anti-collision device, considering the influence of the strain rate on the foam, the formula considering the strain rate effect of the foam is: where σ p (ε) is the non-linear expression of the stress-strain of the foam considering the impact effect; σ(ε) is the non-linear expression of the stress-strain of the foam 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, takes a value of 0.01 - 10 s -1 ; a and b are the strain rate parameters of the foam. Preferably, a = 0.0430 and b = 0.0165.

[0132] S2A4. According to the resistance force F of a single empty circular tube in the inner core structure tubeand the resistance force F of the foam in a single circular tube foam Sum them up to obtain the resistance force F of the circular tube with a single filled foam in the core structure i , where F i = F tube + F foam ;

[0133] S2A5. Calculate the overall resistance force F of the core structure according to the resistance force F of the circular tube with a single filled foam i and the penetration depth δ n and the number n0 of single-layer circular tubes participating in deformation t , where F t = n0F i ;

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

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

[0136]

[0137] where l0 is the length of the outer steel plate before being impacted; ε0 is the critical strain of the steel of the outer steel plate. Preferably, the value of ε0 is 0.05 - 0.1;

[0138] S2B2. Calculate the resistance force F of the outer steel plate according to the critical penetration depth Δ0 and the penetration depth δ n , and the calculation steps are as follows: punch where h1 is the height of the anti-collision device; σ

[0139]

[0140] is the yield stress of the outer steel plate; t y3 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 number of cracks after the steel plate fractures at the penetration depth δ punch , and the value of n2 is 2 - 4; θ1 is half of the expansion angle of the ship; l is the length of the crack at the penetration depth δ n , where l = δ n / tanθ1; μ is the friction coefficient between the outer steel plate and the ship. Preferably, the value of μ is 0.15 - 0.3; n / tanθ1; μ is the friction coefficient between the outer steel plate and the ship. Preferably, the value of μ is 0.15 - 0.3;

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

[0142]

[0143] where π is the pi; σ 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 impact;

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

[0145]

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

[0147]

[0148] where 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 steel plate and the bottom steel plate; H2 is the folding wavelength of the bottom steel plate after impact.

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

[0150]

[0151] S3. Sum the resistance F of the top steel plate, the resistance F of the bottom steel plate, the overall resistance F of the inner core structure, and the resistance F of the outer steel plate at the impact depth δ n to determine the total resistance P of the anti-collision device at the impact depth δ fold1 , where P fold2 = F t + F punch + F n + F f ; f t fold1 fold2 punch <000,000,056>

[0152] S4. Determine whether the impact depth δ n is greater than or equal to the deformable total width L of the anti-collision device; if not, iterate the impact depth δ n and then repeat steps S2, S3, and S4; if so, form the resistance-impact depth curve P n of the anti-collision device based on all impact depths δ n and the corresponding total resistance P f of the anti-collision device; f (δ n ); f (δ n )

[0153] S5. According to the resistance-impact depth curve P f (δ n)Integrate to obtain the energy - penetration depth curve E of the anti - collision device f (δ n ), where

[0154] Through the anti - collision performance analysis method of the steel and UHPC composite anti - collision device of the present invention, considering the resistance - penetration depth relationships of the inner core structure, top steel plate, bottom steel plate and outer steel plate simultaneously, the anti - collision performance of the steel and UHPC composite anti - collision device can be analyzed. Compared with the traditional method of analyzing using a refined finite element model, this method can provide anti - collision performance analysis for the proposed steel - UHPC composite anti - collision device quickly with a certain accuracy, helping technicians determine whether it is necessary to optimize the design of the size of the proposed composite anti - collision device, saving a large amount of computing cost and time, and is applicable to the actual engineering requirements.

[0155] Example 2

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

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

[0158] In this embodiment, according to the pier investigation situation, a proposed steel and UHPC composite anti - collision device is designed. Refer to Figure 6 , after designing the proposed steel and UHPC composite anti - collision device, various parameters of the proposed steel and UHPC composite anti - collision device can be obtained, such as the thickness t punch of the outer steel plate, the thickness t f1 of the top steel plate, the thickness t f2 of the bottom steel plate, the thickness t t of the circular tube in the inner core structure, the length l0 of the outer steel plate before being hit, the length h2 of the circular tube, the diameter D of the circular tube, the radius R of the circular tube in the inner core structure and the total deformable width L of the anti - collision device, etc. Through these parameters, the anti - collision performance of the proposed steel and UHPC composite anti - collision device can be analyzed according to the anti - collision performance analysis method of the steel and UHPC composite anti - collision device in Example 1 to obtain the resistance - penetration depth curve of the anti - collision device, and integrating according to the resistance - penetration depth curve of the anti - collision device can obtain the energy - penetration depth curve of the anti - collision device, and eliminating the intermediate variable (penetration depth) through the resistance - penetration depth curve and energy - penetration depth curve of the anti - collision device can obtain the energy - local peak collision force curve;

[0159] Then, according to the navigation conditions of the fortification requirements, determine the type of the navigation ship and the maximum displacement tonnage mv and the additional mass coefficient C of the navigation speed v0 m . Based on these parameters, the initial total energy E0 to be defended is calculated as follows:

[0160]

[0161] Preferably, C m takes values from 0.1 to 0.3;

[0162] During the ship collision process, the initial total kinetic energy E0 is jointly absorbed by the ship, the bridge pier and the anti-collision device. 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] where, E f is the energy absorbed by the anti-collision device, E v is the energy absorbed by the ship, and E s is the energy absorbed by the bridge pier.

[0164] Determine the configuration of the ship according to the type of the navigation ship, and then determine the resistance-penetration curve of the ship according to the configuration of the ship. Preferably, the resistance-penetration curve of the ship is determined by a refined finite element model; determine the energy-penetration curve of the ship according to the resistance-penetration curve of the ship, and then eliminate the intermediate variable (i.e., the penetration depth) according to the resistance-penetration curve and the energy-penetration curve of the ship to determine the energy-local peak collision force curve of the ship. Determine the resistance-penetration curve of the bridge pier according to the bridge pier structure. Preferably, the resistance-penetration curve of the bridge pier is determined by a refined finite element model; determine the energy-penetration curve of the bridge pier according to the resistance-penetration curve of the bridge pier, and then eliminate the intermediate variable (i.e., the penetration depth) according to the resistance-penetration curve and the energy-penetration curve of the bridge pier to determine the energy-local peak collision force curve of the bridge pier; among them, according to the energy relationship in the collision system, it is obtained that:

[0165]

[0166] where, is the integral of the resistance-penetration curve of the anti-collision device from 0 to the maximum penetration depth a f of the anti-collision device; is the integral of the resistance-penetration curve of the ship from 0 to the penetration depth a v of the ship; is the integral of the resistance-penetration curve of the bridge pier from 0 to the displacement a s of the bridge pier. Preferably, during the optimization design process of the anti-collision device, as a conservative consideration, the energy absorbed by the bridge 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 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, as Figure 6 shown;

[0168] When the energy absorbed by the 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 pier;

[0169] S02: As Figure 6 shown, substitute the initial total energy E0 to be defended into the total energy - local peak collision force curve to determine the local peak collision force P t when absorbing the initial total energy. Calculate the energy E t that the anti - collision device needs to absorb according to the local peak collision force P f ; then, through the energy - penetration depth curve of the anti - collision device and the energy E f that the anti - collision device needs to absorb, determine the maximum penetration depth a f of the anti - collision device;

[0170] S03: As Figure 6 shown, judge whether the local peak collision force P t and the maximum penetration depth a f of the anti - collision device meet the requirements: If both the local peak collision force P t and the maximum penetration depth a f meet the requirements, the design of the anti - collision device is completed; If at least one of the local peak collision force P t and the maximum penetration depth a f does not meet the requirements, the anti - collision device needs to be optimized. After optimization, update the total energy - local peak collision force curve in step SO1, and then repeat steps S02 - S03 until both the local peak collision force P t and the maximum penetration depth a f of the anti - collision device meet the requirements, and the optimization design of the anti - collision device is completed;

[0171] Among them: As Figure 6 shown, the method of judging whether the local peak collision force P t meets the requirements is: Compare the local peak collision force P t with the collision force P v-b between the ship and the pier without considering the anti - collision device. If it satisfies P t ≤(1 - λ p )×P v-b , it means that the proposed anti - collision device meets the requirement of reducing the ship collision force. Among them, λ p is the ship collision force reduction rate to be met. Preferably, λp Take 0.1 to 0.3;

[0172] Among them, the collision force P between the ship and the pier v-b can be determined according to the refined numerical simulation model of ship-bridge collision; preferably, the collision force P between the ship and the pier without considering the anti-collision device 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 the value of 0.033; η is the correction coefficient of geometric dimensions, preferably, η takes the value of 1.0; β is the correction coefficient of the impact angle, preferably, β takes the value of 1.0.

[0175] As Figure 6 shown, the method for judging whether the maximum penetration depth a of the anti-collision device meets the requirements is: compare the maximum penetration depth a of the anti-collision device f with the total deformable width L of the anti-collision device designed as proposed. If a f ≤ λ f × L, it means that the anti-collision device designed as proposed meets the requirements for reducing the ship collision force. Among them, λ a is the maximum allowable deformation rate of the anti-collision device. Preferably, λ a takes 0.7 to 0.9. a Take 0.7 to 0.9.

[0176] The optimized 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, piers and anti-collision devices. This method can accurately predict the peak collision force and the penetration depth of the anti-collision device according to the ship speed and the displacement tonnage of the ship, and ensure that the anti-collision device meets the requirements in terms of reducing the ship collision force and controlling deformation through multiple calculations. Compared with the traditional optimization process that relies on refined numerical models, this method is more rapid and convenient, avoiding the time and cost consumption caused by frequent modeling, calculation and adjustment in the traditional method, and significantly improving the design efficiency.

[0177] Application case:

[0178] The piers of a certain cross-river bridge are located in the main navigation channel area, and the piers are at high risk of being impacted by ships. Therefore, it is necessary to design a steel and UHPC combined anti-collision device 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 certain steel and UHPC combined anti-collision device, first use the above anti-collision performance analysis method for the steel and UHPC combined anti-collision device to conduct anti-collision performance analysis, which is as follows:

[0180] Step O1: Determine the maximum displacement tonnage m of the ship according to the analysis of the waterway grade and navigable flow rate v = 2750t, the maximum navigable speed v0 = 4m / s, and the additional mass coefficient to be considered is C m = 0.1;

[0181] Step 02: Obtain relevant parameters according to the designed steel and UHPC combined anti-collision device for this river-crossing bridge. The height h1 of the designed anti-collision device is 3.0m, the total deformable width L is 2.0m, and the thicknesses of the outer steel plate, top steel plate, and bottom steel plate are all 10mm, and the yield stress σ y1 = σ y2 = σ y3 = σ y0 = 295MPa, the plastic strain hardening modulus E P = 1600MPa, the platform stress σ of the foam p = 0.18MPa, the densification strain ε D = 0.2, the material parameter k = 2.28MPa, n = 3.79, the D of the vertical circular tube in the inner core structure is 1.0m, and according to the ship-anti-collision device collision relationship, the number of single layers of vertical circular tubes participating in deformation and energy absorption n0 = 4, and the number of layers n1 = 2;

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

[0183] Step 04: According to Figure 3 the anti-collision performance analysis process shown, calculate the resistance - collision depth relationship of the top (bottom) steel plate in the steel and UHPC combined anti-collision device according to steps S2 - S4, as shown in Figure 7 (c). Since the thicknesses of the top steel plate and the bottom steel plate are the same, the calculation results are the same, and only the calculation of one of them needs to be done;

[0184] Step 05: According to Figure 3 the anti-collision performance analysis process shown, assume the collision depth change Δδ = 0.01, and calculate the resistance - collision depth relationship of the outer steel plate in the steel and UHPC combined anti-collision device 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 - penetration depth curve of the steel and UHPC combined anti - collision device, as shown in Figure 8 (a), and at the same time, the energy - penetration depth curve of the steel and UHPC combined anti - collision device can be determined as shown in Figure 8 (b);

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

[0187] Next, use the above - mentioned optimization design method of a steel and UHPC combined anti - collision to optimize the design of the anti - collision device. The specific process is as follows:

[0188] Step 07: According to the above - mentioned anti - collision performance analysis method of a steel and UHPC combined anti - collision device, determine the anti - collision performance of the proposed design combined anti - collision device, as shown on the right - hand side; Figure 9 as shown on the right - hand side;

[0189] Step 08: The displacement tonnage m of a typical ship in this navigable water area v = 2750 t, the maximum ship speed v0 of the ship = 4 m / s, and the added - mass coefficient C m = 0.1. Therefore, according to the formula, the maximum initial total energy E0 to be fortified can be calculated as E0 = 24.2 MJ;

[0190] Step 09: By establishing a refined finite - element model of the ship, obtain the resistance - penetration depth curve of the ship as shown on the left - hand side; Figure 9 as shown on the left - hand side;

[0191] Step 10: According to the resistance - penetration depth curve of the ship and the resistance - penetration depth curve of the anti - collision device, convert them into energy - penetration depth curves, and establish a peak - force - energy relationship curve graph as shown in Figure 10 The left - hand side is the energy - penetration depth relationship curve of the ship and the anti - collision device, and the right - hand side is the relationship between the peak force, energy consumption of the ship and the anti - collision device;

[0192] Step 11: Substitute the maximum initial total energy E0 = 24.2 MJ into the right - hand side, and it can be determined that when the absorbed energy is 24.2 MJ, P Figure 10 = 16.97 MN, the energy E absorbed by the ship t ​v = 11.21 MJ, the energy E absorbed by the anti-collision device f = 12.99 MJ;

[0193] Step 13. According to the energy E absorbed by the ship v = 11.21 MJ, substitute it into Figure 10 The collision depth a of the ship can be determined on the left side v = 1.21 m. According to the energy E absorbed by the anti-collision device f = 1299 MJ, substitute it into Figure 10 The collision depth a of the anti-collision device can be determined on the left side f = 1.68 m;

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

[0195] Step 15. Without changing the configuration of the steel and UHPC composite anti-collision device, design the steel plate thickness to be 12 mm, and repeat steps 07 - 13. The collision response of the steel and UHPC composite anti-collision device with increased steel plate thickness is as Figure 11 shown. Through calculation, it can be obtained that P t = 16.97 MN, which is greater than (1 - λ p )×P v-b = 14.24 MN; a f = 1.56 m, which meets the requirement of being less than λ a ×L = 1.6 m. By comparison, it can be seen that the designed steel and UHPC composite anti-collision device does not meet the technical requirements;

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

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

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

[0199] Operating condition 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 calculation efficiency of the anti-collision performance analysis and optimization design method of the steel and UHPC combined anti-collision device proposed by the present invention is significantly better than that of the traditional refined finite element model. Specifically, this method can obtain the anti-collision performance 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 takes dozens of hours or even longer calculation 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 input cost of the project. Therefore, the method of the present invention has good engineering applicability, can quickly respond to the demand changes in the design stage, effectively improves the design and optimization efficiency, and is especially suitable for rapid pre-evaluation and optimization adjustment in actual engineering.

[0201] In summary, the present invention provides an anti-collision performance analysis method for a steel and UHPC combined anti-collision device, which can quickly predict the anti-collision performance of the anti-collision device, make up for the deficiencies of the existing technology, and significantly improve the design efficiency of the anti-collision device; at the same time, the present invention also provides an optimization design method for a steel and UHPC combined anti-collision device, which can quickly predict various collision responses during the ship impact process and accurately judge whether it meets the design requirements, thereby effectively improving the optimization efficiency of the anti-collision device.

[0202] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for analyzing the crashworthiness of a combined steel and UHPC anti-collision device, characterized in that, It includes the following steps: S1. Determine the structural dimension parameters of the steel and UHPC composite anti-collision device in the proposed design; The steel and UHPC composite anti-collision device includes: a UHPC panel, a box body, and an inner core structure. The box body includes 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 tops of the inner steel plate and the outer steel plate, the bottom steel plate is connected to the bottoms of the inner steel plate and the outer steel plate, the UHPC panel is connected to the outside of the outer steel plate and the inner steel plate, and the inner core structure is arranged inside the box body; when a ship impacts 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 impact depth δ according to the structural dimensions of the steel and UHPC combined anti-collision device designed as per the plan n The resistance F of the lower top steel plate fold1 and the resistance F of the bottom steel plate fold2 and the overall resistance F of the inner core structure t and the resistance F of the outer steel plate punch ; S3. Determine the penetration depth δ n The resistance force F of the lower top steel plate fold1 , the resistance force F of the bottom steel plate fold2 , the overall resistance force F of the inner core structure t and the resistance force F of the outer steel plate punch Sum them up to determine the penetration depth δ n The total resistance force P of the lower anti-collision device 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, iterate the impact depth δ n And then repeat steps S2, S3, and S4; if so, based on all impact depths δ n And the impact depth δ n Corresponding to the total resistance P of the anti-collision device f Form the resistance-impact depth curve P of the anti-collision device f (δ n ); S5. According to the resistance - penetration depth curve P of the anti - collision device f (δ n ) perform integration to obtain the energy - penetration depth curve E of the anti - collision device f (δ n ), where 2. The anti-collision performance analysis method of a steel and UHPC combined anti-collision device according to claim 1, characterized in that The inner core structure adopts vertically arranged circular tubes filled with foam in a layered manner. The number of single-layer circular tubes participating in deformation during ship impact is n0, and the number of layers is n1; The overall resistance force F of the inner core structure described in step S2 t The calculation process is as follows: S2A1. Determine the impact depth δ of a single circular tube based on the impact depth δ n where the impact depth δ of a single circular tube t is determined as t δ = δ n / n1; S2A2. Calculate the resistance force F of a single hollow circular tube in the inner core structure based on the impact depth δ of a single circular tube t and the structural dimensions and material properties of the anti-collision device tube ; S2A3. Calculate the resistance force F of the foam in a single circular tube in the inner core structure based on the impact depth δ of a single circular tube t , the structural dimensions and material properties of the anti-collision device foam ; S2A4. Obtain the resistance force F of a single foam-filled circular tube in the inner core structure based on the resistance force F of a single empty circular tube in the inner core structure tube and the resistance force F of the foam in a single circular tube foam by summing them up, to obtain the resistance force F of a single foam-filled circular tube in the inner core structure i , where F i = F tube + F foam ; S2A5. Calculate the overall resistance force F of the inner core structure based on the resistance force F of a single round tube filled with foam and the impact depth δ i and the number n0 of single-layer round tubes participating in deformation n to calculate the overall resistance force F of the inner core structure, where F t = n0F t . i .

3. The anti-collision performance analysis method of a steel and UHPC combined anti-collision device according to claim 1, characterized in that The resistance force F of the outer steel plate described in step S2 punch is calculated as follows: S2B1. Calculate the critical collision depth Δ0 before the outer steel plate fractures and fails: Where, l0 is the length of the outer steel plate before being impacted; ε0 is the critical strain of the outer steel plate material; S2B2. Calculate the resistance force F of the outer steel plate based on the critical impact depth Δ0 and the impact depth δ n The calculation steps are as follows: punch to calculate the resistance force F of the outer steel plate Among them, 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 number of cracks after the lower steel plate fractures, and the value of n2 is 2 - 4; l is the length of the lower crack at the collision depth δ n , where n2 takes values from 2 to 4; l is the length of the lower crack at the collision depth δ n , 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 the value of μ is 0.15 - 0.

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4. The anti-collision performance analysis method of a steel and UHPC combined anti-collision device according to claim 1, characterized in that, The resistance force F of the top steel plate described in step S2 fold1 The calculation process is as follows: where π is the ratio of a circle's circumference to its diameter; σ 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 and bottom steel plates; H1 is the folding wavelength of the top steel plate after impact; The resistance force F of the bottom steel plate described 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 steel plate and the bottom steel plate; H2 is the folding wavelength of the bottom steel plate after impact.

5. The anti-collision performance analysis method of a steel and UHPC combined anti-collision device according to claim 2, characterized in that, The resistance force F of the single empty circular tube described in step S2A2 tube The calculation process is as follows: A2.

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

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

3. Calculate the resistance force F of a single empty circular tube in the inner core structure tube : Where, 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 hardening section and the rigid section during 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. Combining with the resistance formula of a single empty circular tube in the inner core structure and the initial resistance F tube of the empty circular tube in the inner core structure, the following can be obtained: tube，0 Among them, λ, q, ζ, and m are all deformation coefficients of the hardening section of the circular tube after considering the mutual restraint of multiple circular 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 hardening section and the rigid section during 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 hardening section and the rigid section during the transverse crushing of the circular tube is: Where, θ is the angle operation parameter; The resistance force F of the foam in a single empty circular tube described in step S2A3 foam is calculated as follows: where D is the diameter of the circular tube; h2 is the length of the circular tube; σ p is the plateau 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 are determined according to the stress-strain curve of the foam, and the function of the stress-strain curve of the foam is: where ε is the strain of the foam; σ f is the stress of the foam at strain ε.

6. The anti-collision performance analysis method of a steel and UHPC combined anti-collision device according to claim 4, characterized in that, The calculation formula of the folding wavelength H1 of the top steel plate after being impacted is: The calculation formula of the folding wavelength H2 of the bottom steel plate after being impacted is:

7. The anti-collision performance analysis method of a steel and UHPC combined anti-collision device according to claim 5, characterized in that During the process of a ship hitting the anti-collision device, considering the influence of the strain rate on the circular steel tube, the yield stress σ of the circular tube y0 is calculated by the formula: where is the reference strain rate under ship impact; P and X are the strain rate parameters of the circular steel tube; σ′ y0 is the yield strength of the circular steel tube in a quasi-static uniaxial test.

8. The anti-collision performance analysis method of a steel and UHPC combined anti-collision device according to claim 5, characterized in that, During the process of a ship hitting the anti-collision device, considering the influence of the strain rate on the foam, the formula considering the strain rate effect of the foam is: Among them, σ p (ε) is the non-linear expression of the foam stress-strain considering the impact effect; σ(ε) is the non-linear expression of the 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 the ship; a and b are the strain rate parameters of the foam.

9. An optimization design method for a combined steel and UHPC anti-collision device, characterized in that, It includes the following steps: S01: According to the anti-collision performance analysis method of the steel and UHPC composite anti-collision device described in any one of claims 1-8, first determine the resistance-collision depth curve and energy-collision depth curve of the proposed steel and UHPC composite anti-collision device, and further derive the energy-local peak collision force curve of the anti-collision device based on these two curves; Meanwhile, according to the navigable conditions required for flood prevention, determine the maximum displacement tonnage m of the navigable vessels v , the navigable speed v0, and the added mass coefficient C m . Based on these parameters, calculate the initial total energy E0 to be protected as follows: At the same time, determine its configuration according to the ship type, and thus obtain the resistance-collision depth curve of the ship, and then derive the energy-collision depth curve of the ship; through the resistance-collision depth curve and energy-collision depth curve of the ship, determine the energy-local peak collision force curve of the ship; When not considering the energy absorption of the bridge pier, 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-collision depth curve of the bridge pier based on the structural characteristics of the bridge pier, and derive its energy-collision depth curve and energy-local peak collision force curve; then, by integrating the energy-local peak collision force curves of the anti-collision device, the ship, and the bridge pier, determine the total energy-local peak collision force curve; 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 , and calculate the energy E that the anti-collision device needs to absorb according to the local peak collision force P t ; Subsequently, through the energy - penetration depth curve of the anti-collision device and the energy E that the anti-collision device needs to absorb f , determine the maximum penetration depth a of the anti-collision device f ; f ; S03: Determine the local peak collision force P t and the maximum penetration depth a of the anti-collision device f to check if they meet the requirements: If both the local peak collision force P t and the maximum penetration depth a of the anti-collision device f meet the requirements, the design of the anti-collision device is completed; If at least one of the local peak collision force P t and the maximum penetration depth a of the anti-collision device f does not meet the requirements, the anti-collision device needs to be optimized. After optimization, update the total energy - local peak collision force curve in step S01, and then repeat steps S02 - S03 until both the local peak collision force P t and the maximum penetration depth a of the anti-collision device f meet the requirements, and the optimization design of the anti-collision device is completed; Among them, the method for judging whether the local peak collision force P t meets the requirements is as follows: compare the local peak collision force P t with the collision force P v-b between the ship and the pier without considering the anti-collision device. If P t ≤(1 - λ p )×P v-b , it indicates that the designed anti-collision device meets the requirement of reducing the ship collision force; where λ p is the reduction rate of the ship collision force that needs to be met. Determine the maximum impact depth a of the anti-collision device f The method to determine whether the requirement is met is as follows: Compare the maximum impact depth a of the anti-collision device f with the total deformable width L of the anti-collision device designed as intended. If a f ≤λ a ×L, it indicates that the anti-collision device designed as intended meets the requirement of reducing the ship collision force; where λ a is the maximum allowable deformation rate of the anti-collision device.

10. The optimized 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 as follows: P v-b = zηβv0[(1 + C M )m v 0.62 ;​ Where, z is the ship collision force coefficient; η is the correction coefficient of geometric dimensions; β is the correction coefficient of the impact angle.

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