Natural absorption layer for underwater component laser peening and application of natural absorption layer

Abstract

The invention discloses a natural absorption layer for underwater component laser peening and application of the natural absorption layer, and belongs to the technical field of material surface life prolonging. According to the method, a biological membrane with gradient optical characteristics is formed through in-situ induction of marine microbial communities to serve as a natural absorption layer, dynamic adaptation of laser peening parameters and the state of the biological membrane is achieved in combination with a multi-physical field coupling regulation and control technology, surface strengthening and corrosion synergistic inhibition are synchronously completed, and finally eco-friendly underwater life prolonging treatment is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of extending the life of material surfaces, and in particular relates to a natural absorption layer for laser shot peening of underwater components and an application thereof. Background Art

[0002] As ocean engineering projects continue to develop in deeper waters and larger scale, underwater metal structures and components face the challenge of long-term damage from the combined effects of corrosion and fatigue in complex environments. Marine infrastructure operates or serves continuously in environments with high pressure, high salinity, and high microbial content.

[0003] Traditional surface protection technologies have significant shortcomings in terms of ecological adaptability and long-term protection. Due to the environmental impact of deepwater, existing organic coating systems are susceptible to erosion and biofouling, leading to interfacial delamination or failure. This necessitates frequent underwater maintenance, which not only increases operating costs but also releases chemicals that conflict with marine environmental protection requirements.

[0004] Technical barriers to the underwater application of laser surface enhancement technology severely limit its widespread adoption in marine engineering. Laser surface enhancement technology faces multiple physical obstacles when applied underwater, including a significant decrease in laser energy transmission efficiency due to the dynamic fluid environment and the inability of conventional absorbing materials to meet the requirements for long-term, stable underwater operation. The auxiliary protective layer used in traditional processes suffers from insufficient interfacial bonding strength, resulting in detached fragments that can cause secondary environmental contamination. Furthermore, the layer cannot effectively prevent microbial attachment and erosion in the enhanced area, instead creating new corrosion vulnerabilities. Summary of the Invention

[0005] In order to solve the deficiencies of the prior art, the purpose of the present invention is to provide a natural absorption layer for laser shot peening of underwater components and its application.

[0006] The technical principle of this invention is based on the light energy conversion properties of marine biofilms and a multi-physics field synergistic regulation mechanism. Natural biofilms form a gradient absorption structure through the synergistic effect of algal photosynthetic pigments and bacterial extracellular polymers. The gradient distribution of the dielectric constant enhances laser energy absorption efficiency and reduces reflection loss. Dynamic matching of biofilm thickness and laser penetration depth is achieved through an optical-fluidic-mechanical coupling model. Real-time monitoring of the biofilm's optical properties (such as phycocyanin content) and fluid parameters (flow rate, shear force) establishes an inverse relationship between pulse energy and film thickness. High peak power is used in thin regions to enhance energy deposition, while in thick regions, the stress wave duration is prolonged to increase the depth of plastic deformation. The corrosion inhibition mechanism of microbial metabolism relies on the oxygen concentration gradient regulated by photosynthesis and the passivation effect of antimicrobial secretions. Photothermal triggering guides microbial enrichment and repair of defective areas. Shock wave propagation path optimization relies on the turbulent confinement layer formed by natural water flow. Vortex guidance technology is used to adjust the plasma expansion direction, directing the shock wave energy to the subsurface of the material, inducing the formation of a gradient nanocrystalline structure. The biofilm degradation process follows the self-purification law of marine ecology, and its metabolites are environmentally friendly digested through fluid diffusion and microbial decomposition.

[0007] In order to achieve the above object, the technical solution of the present invention is: In a first aspect, the present invention provides a natural absorption layer for laser shot peening of underwater components. The surface of the underwater in-service component is covered with a natural absorption layer, and the natural absorption layer is an in-situ biofilm obtained by directional induction and regulation based on the algae-bacteria symbiotic system; The algae-bacteria symbiotic system includes photosynthetic cyanobacteria and Pseudoalteromonas; Using a dynamic spectral control strategy, the biofilm grew naturally under controlled water flow conditions, with a biofilm thickness of 65±5 μm and a phycocyanin content stable at 1~2 mg / cm 2 , forming a natural absorption layer.

[0008] In one or more embodiments, alternating irradiation with 440-460 nm blue light and 670-690 nm red light is used, with a water flow rate of 0.3-0.8 m / s and natural growth for 15-25 days. The 440-460 nm blue light promotes the synthesis of algae photosynthetic pigments, while the 670-690 nm red light enhances light energy conversion efficiency. Alternating irradiation avoids the inhibition of metabolism by monochromatic light.

[0009] As a further technical solution, a hybrid biofilm is induced on the surface of the target in-service component. The biofilm has a two-layer structure: an inner layer of Pseudoalteromonas membrane (for adhesion) and an outer layer of photosynthetic cyanobacteria membrane (for light absorption). The difference between the thickness of the outer and inner layers is 2-10 μm, preferably 4-6 μm. The outer layer is thicker than the inner layer.

[0010] In a second aspect, the present invention provides the use of the above-mentioned natural absorption layer for laser shot peening of underwater components in the life extension treatment of in-service components in a water environment, wherein the water environment includes seawater, ordinary water, and the like.

[0011] In a third aspect, the present invention provides a life extension treatment process for underwater in-service components, comprising the following steps: 1) Constructing the above-mentioned natural absorption layer on the surface of the target in-service component; 2) Construct a multi-source sensing network to monitor various parameters of the in situ biofilm in real time, establish an energy transfer model for light energy conversion efficiency, and achieve dynamic adaptation of laser parameters to the in situ biofilm state; 3) In the laser-impacted area, an electrochemical-fluid coupling control system is established using synergistic inhibition of microbial corrosion. This synergistic inhibition of microbial corrosion includes regulating the interfacial oxygen concentration gradient through photosynthesis, utilizing microbial secretion of antimicrobial and / or passivating substances, optimizing surface microstructure design, and combining intelligent response materials to achieve dynamic repair of damaged areas. 4) Conduct post-impact processing and evaluation.

[0012] In one or more embodiments, in step 1), the in-service component refers to a metal structural material or component in an underwater environment.

[0013] In one or more embodiments, in step 1), the specific steps include: screening the algae-bacteria symbiotic system; using a dynamic spectral control strategy to activate the metabolic activity of the target microorganisms; designing a bionic diversion structure to optimize the local flow field distribution based on the fluid environment characteristics of the component surface; maintaining the ecological balance of the microbial community through a slow-release nutrient supply system, and implementing periodic laser trimming based on real-time monitoring data.

[0014] As a further technical solution, an algae-bacteria symbiotic system with photon energy conversion and interfacial adhesion properties was selected to form a biofilm with gradient optical properties and different functions at different depths. The algae-bacteria symbiotic system comprises photosynthetic cyanobacteria and Pseudoalteromonas. The prepared biofilm has a double-layer structure: the inner Pseudoalteromonas membrane has adhesion function, and the outer photosynthetic cyanobacteria membrane has light absorption function.

[0015] As a further technical solution, activation conditions include irradiating the target microorganisms with a specific wavelength combination to activate metabolic activity and inhibit the colonization of corrosive bacteria. This specific wavelength combination consists of alternating irradiation with blue light between 440 and 460 nm (e.g., 450 nm) and red light between 670 and 690 nm (e.g., 680 nm). The 440-460 nm blue light promotes the synthesis of algae photosynthetic pigments, while the 670-690 nm red light enhances light energy conversion efficiency. Alternating irradiation prevents metabolic inhibition by monochromatic light.

[0016] Specifically, a hybrid biofilm is induced on the surface of the target in-service component using a dynamic spectral control strategy (wavelength combination: alternating irradiation with 450 nm blue light and 680 nm red light). The biofilm is allowed to grow naturally for 15 to 25 days (e.g., 21 days) under controlled seawater flow rates of 0.3 to 0.8 m / s (flow rates > 0.8 m / s will cause shearing of the biofilm, while flows < 0.3 m / s will affect nutrient exchange). The biofilm thickness reaches 65 ± 5 μm (thickness < 60 μm, insufficient light absorption layer results in laser energy deposition efficiency < 80%, while thickness > 70 μm hinders stress wave transmission), and the phycocyanin content is stabilized at 1 to 2 mg / cm 2 (e.g. 1.2 mg / cm 2 )(phycocyanin <1 mg / cm 2 Insufficient absorption, >2 mg / cm 2 Otherwise, the film layer is too dense, which affects the laser penetration), forming a natural absorption layer with gradient absorption characteristics.

[0017] As a further technical solution, the bionic guide structure is designed to optimize the local flow field distribution based on the fluid environment characteristics on the component surface. Specifically, the water flow is guided to form a directional vortex through the bionic guide groove on the component surface (such as the shark skin rib structure), so that the shock wave energy is transmitted along the material direction.

[0018] As a further technical solution, a slow-release nutrient supply system is used to maintain the ecological balance of the microbial community, and periodic laser trimming is performed based on real-time monitoring data to remove aging membrane layers and activate self-repair functions to ensure the light absorption efficiency and structural stability of the biofilm. The slow-release nutrient supply system consists of nutrient-rich particles coated with a porous silicate carrier. Nitrogen and phosphorus solutions are loaded into the pores of diatomaceous earth microspheres through vacuum impregnation. The system is then coated with a sodium alginate-chitosan composite membrane to create a pH / light-responsive release mechanism. This system, which accelerates degradation at pH > 7.5, dynamically maintains a metabolic environment with a nitrogen-phosphorus ratio of 10 to 15:1, effectively inhibiting the colonization of sulfate-reducing bacteria.

[0019] The slow-release nutrient supply system maintains a metabolic environment with a nitrogen-phosphorus ratio of (10-15):1 (a nitrogen-phosphorus ratio <10 promotes the proliferation of corrosive bacteria, while a nitrogen-phosphorus ratio >15 destroys the algae-bacteria balance), thereby inhibiting the colonization of sulfate-reducing bacteria.

[0020] Periodic laser trimming is performed based on real-time monitoring data. Based on the biofilm thickness data fed back by the fiber optic sensor in real time, the system automatically adjusts the laser parameters. For example, when the biofilm thickness is >70 μm or the phycocyanin is <1 mg / cm 2 When the aging layer is ablated, a low-energy laser (4-6 J, 8-12 ns, for example, 5 J, 10 ns) is triggered, and nutrient particles (50-100 g / m2 ) increases the growth rate of new membrane by 40%.

[0021] In one or more embodiments, in step 2), the multi-source sensing network is constructed as a monitoring system consisting of a fiber optic sensor (biofilm thickness), a multispectral imager (light absorption characteristics), and an acoustic Doppler flowmeter (fluid parameters). Multiple physical conditions or equipment detect different biological or physical characteristics. Specifically, for example, the fiber optic sensor monitors biofilm thickness, the multispectral imager analyzes phycocyanin distribution, and the acoustic Doppler flowmeter collects flow field data.

[0022] In one or more embodiments, in step 2), the real-time monitoring of various parameters of the in-situ biofilm includes parameters such as the thickness of the in-situ biofilm, light absorption characteristics, and fluid parameters, so as to establish an energy transfer model for light energy conversion efficiency.

[0023] The establishment of the energy transfer model for light energy conversion efficiency includes: adjusting the laser pulse energy, pulse width and spot distribution according to the various parameters of the in-situ biofilm monitored in real time, designing a turbulent confinement layer in combination with natural water flow, and optimizing the plasma expansion and shock wave propagation path. The specific steps include: implementing dynamic parameter adjustment, adaptively adjusting the laser pulse energy, pulse width and spot distribution according to the in-situ biofilm state. The thin layer area (the area with biofilm thickness <60 μm) uses a high peak power mode (25-30 J high peak mode, peak power density 5-10 GW / cm 2 Energy deposition is enhanced by prolonging the stress wave action time (extending the pulse width to 35-40 ns) in thick regions (thickness >70 μm) to increase the depth of plastic deformation. For example, when the sensor detects a thickness <60 μm, the system switches to a high-peak mode of 25-30 J; for thickness >70 μm, the pulse width is extended to 35-40 ns. A turbulence confinement layer is designed incorporating natural water flow (natural water flow passes through biomimetic flow channels (e.g., shark skin ribs) to form directional vortices, constraining the direction of plasma expansion and directing shock wave energy along the material normal (increasing energy utilization by 35%)). Plasma expansion and shock wave propagation paths are optimized based on near-normal incidence. Vortex guidance techniques, such as surface flow channels, constrain the direction of plasma expansion and increase shock wave penetration depth, enhancing the shock wave's effect on the material surface. An integrated acoustic-optical feedback system (acoustic sensors monitor shock wave intensity, while optical sensors capture plasma luminescence signals) is also implemented. Machine learning technology parses multi-physics field data, dynamically optimizes process conditions such as laser parameters, and coordinates the matching of laser energy, biofilm status, and environmental conditions throughout the entire process. For example, the LSTM algorithm is used to analyze the acoustic-optical sensor data stream and optimize laser parameters such as energy or pulse width in real time.

[0024] As a further technical solution, the laser pulse energy is 20-30 J, for example, 20, 23, 25, 28, 30 J, etc., preferably 24-26 J. The pulse width is 20-40 ns, for example, 20, 25, 30, 35, 40 ns, etc., preferably 25-35 ns. The spot diameter is 5-10 mm, for example, 5, 6, 7, 8, 9, 10 mm, etc., preferably 5-7 mm. When the energy is <20 J, the residual compressive stress is <-250 MPa (insufficient strengthening), while when the energy is >30 J, the biomembrane will be penetrated. When the pulse width is <20 ns, the stress wave effect is short, and when the pulse width is >40 ns, the heat-affected zone expands. The overlap ratio is 70-90%, for example, 70%, 75%, 80%, 85%, 90%, etc., but is not limited to the values ​​listed above. All other values ​​not listed but within the above ranges are within the scope of protection of this invention.

[0025] The turbulence confinement layer is designed based on a natural water flow with a flow rate of 1-5 m / s, such as 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, and 5 m / s, with 1-2 m / s being preferred. A flow rate <1 m / s will not form an effective turbulence confinement layer, and a flow rate >5 m / s will interfere with plasma stability.

[0026] In one or more embodiments, in step 3), regulating the interfacial oxygen concentration gradient by photosynthesis means that the cyanobacteria photosynthesis reduces the interfacial oxygen concentration gradient by 40%, thereby inhibiting the electrochemical corrosion process.

[0027] As a further technical solution, microorganisms are used to secrete antibacterial substances and / or passivating substances. The microorganisms are beneficial microorganisms, and the beneficial microorganisms refer to (photosynthetic cyanobacteria that secrete antimicrobial peptides and Pseudoalteromonas that secrete extracellular polymers). They secrete antibacterial substances and passivating substances. The antibacterial substance refers to (photosynthetic cyanobacteria) and the passivating substance refers to (Pseudoalteromonas).

[0028] As a further technical solution, the surface microstructure design is optimized, and the water flow is guided to form a directional vortex through bionic guide grooves on the component surface (such as shark skin rib structure), so that the shock wave energy can be transmitted along the material direction.

[0029] As a further technical solution, the dynamic repair of damaged areas can be achieved by incorporating intelligent responsive materials. These materials are thermosensitive hydrogels. The damaged area is defined as a region exhibiting ablation or other damage characteristics, where changes in surface integrity parameters have occurred. Specifically, when the local temperature rises above 32°C, the thermosensitive hydrogel releases repair microorganisms, secreting calcium carbonate to fill microcracks.

[0030] In one or more embodiments, in step 4), the specific steps include: starting the natural degradation program of the biofilm, in-situ monitoring and tracking the film peeling process and the environmental migration path of the degradation products; using non-contact detection technology to analyze the residual stress distribution, micromorphology and sub-surface defect evolution law on the surface of the component, and quantifying the effect of laser shock on improving material properties; deploying a long-term monitoring system in a simulated and real marine environment, collecting key performance data such as stress corrosion and biofouling, and constructing a digital twin model to invert the mapping relationship between process parameters and service behavior.

[0031] As a further technical solution, the biofilm's natural degradation process is initiated after human intervention ceases, allowing in situ monitoring to track the film's detachment and the environmental migration paths of degradation products. After the cessation of light and nutrient supply, apoptosis of the cyanobacteria triggers the release of intracellular enzymes (cyanases), initiating the EPS hydrolysis process. In situ monitoring is achieved using fluorescent labeling (FITC-EPS).

[0032] As a further technical solution, the non-contact detection technology includes X-ray diffractometer (residual stress), confocal microscope (micromorphology) and ultrasonic phased array (sub-surface defects).

[0033] As a further technical solution, a long-term monitoring system is deployed in a simulated and real marine environment to collect key performance data such as stress corrosion and biofouling, and to build a digital twin model to invert the mapping relationship between process parameters and service behavior. For example, a BP neural network is used to establish a mapping relationship between process parameters and service performance (such as overlap rate). η and corrosion rate V corr Specifically, the learning capabilities of a BP neural network are leveraged, taking process parameters (such as laser pulse energy, pulse width, and spot overlap ratio) as input and service performance (such as corrosion rate and biofilm lifespan) as output. The network is trained using extensive historical data to learn the inherent relationship between these two parameters. Subsequently, simply inputting new process parameters allows the network to quickly estimate the corresponding service performance based on this learned mapping, facilitating process optimization and performance prediction.

[0034] Machine learning algorithms enable the dynamic evolution of the technology system (establishing a mapping relationship between process parameters and service performance through a BP neural network), forming an intelligent response process knowledge base adapted to the characteristics of different sea areas (automatically increasing the pulse width by 10% for high turbidity sea areas (such as the Bohai Sea) and increasing the pulse energy by 5% for high salinity sea areas (such as the Red Sea) (based on digital twin model feedback)), completing the closed-loop transformation from experimental verification to engineering application.

[0035] As a preferred technical solution, the treatment process specifically includes: S1: Directed induction and regulation of in situ biofilms A natural absorption layer based on marine microbial communities is constructed on the surface of the target component. Algal-bacterial symbiotic systems with light energy conversion and interfacial adhesion properties are selected to form a biofilm with gradient optical properties. A dynamic spectral control strategy is adopted to activate the metabolic activity of the target microorganisms with illumination using a specific wavelength combination, inhibiting the colonization of corrosive bacteria. In combination with the fluid environment characteristics on the component surface, a biomimetic diversion structure is designed to optimize the local flow field distribution, reduce shear force impact in high-velocity areas, and promote uniform biofilm adhesion. A slow-release nutrient supply system is used to maintain the ecological balance of the microbial community. Periodic laser trimming is implemented based on real-time monitoring data to remove aging film layers and activate self-repair functions, ensuring the biofilm's light absorption efficiency and structural stability. An integrated environmental adaptive mechanism dynamically couples light cycles, temperature fluctuations, and natural water flows to form an ecological absorption layer adapted to the marine environment.

[0036] S2: Dynamic adaptation of laser parameters to biofilm state A multi-source sensing network is constructed to monitor biofilm thickness, light absorption characteristics, and fluid parameters in real time, and an energy transfer model for light energy conversion efficiency is established. A dynamic parameter adjustment system is developed to adaptively adjust the laser pulse energy, pulse width, and spot distribution according to the state of the biofilm. High peak power mode is used to enhance energy deposition in thin-layer areas, and stress wave action time is prolonged in thick-layer areas to increase the depth of plastic deformation. A turbulent confinement layer is designed in conjunction with natural water flow to optimize plasma expansion and shock wave propagation paths. Vortex guidance technology is used to enhance the effect of shock waves on the material surface. An integrated acoustic-optical joint feedback system is used, and machine learning technology is used to analyze multi-physics field data, dynamically optimize the spot overlap rate and scanning path, and coordinately match laser energy, biofilm status, and environmental conditions throughout the entire process.

[0037] S3: Construction of synergistic inhibition system for microbial corrosion Establish a synergistic protection mechanism between microbial metabolism and material surface in the laser impact zone. Photosynthesis regulates the interfacial oxygen concentration gradient and inhibits the electrochemical corrosion process. Utilize beneficial microorganisms to secrete antibacterial substances and passivation products to construct a composite protective layer of physical barrier and chemical inhibition. Optimize the surface microstructure design to promote material exchange and metabolite migration within the protective layer, and combine intelligent response materials to achieve dynamic repair of damaged areas. Establish an electrochemical-fluid coupling control system to monitor interfacial potential fluctuations in real time and compensate for local microenvironmental changes. The photothermal triggering mechanism guides microorganisms to enrich and regenerate in defective areas, forming an adaptive long-term protection network. Develop a multi-dimensional evaluation system to collaboratively analyze mechanical properties, electrochemical characteristics, and interfacial bonding state, and dynamically optimize the interaction between the protective layer and the marine environment.

[0038] S4: Post-impact processing and performance evaluation After terminating human intervention, the natural degradation process of the biofilm is initiated, and in-situ monitoring is carried out to track the film peeling process and the environmental migration path of the degradation products. Marine fluid dynamics promote the diffusion of residues, and microbial decomposition achieves eco-friendly digestion. Non-contact detection technology analyzes the surface residual stress distribution, micromorphology, and evolution of sub-surface defects, and quantifies the effect of laser shock on material performance improvement. Long-term monitoring systems are deployed in simulated and real marine environments to collect key performance data such as stress corrosion and biofouling, and a digital twin model is constructed to invert the mapping relationship between process parameters and service behavior. Machine learning algorithms enable the dynamic evolution of the technology system, forming an intelligent response process knowledge base adapted to the characteristics of different sea areas, and completing the closed-loop transformation from experimental verification to engineering application.

[0039] As a specific embodiment, the present invention provides a process for extending the life of an offshore wind power pile foundation, comprising: (1) Construction of in situ biofilm absorption layer A mixed diatom-cyanobacteria biofilm is induced on the surface of offshore wind turbine pile foundations. Using a dynamic spectral control strategy, it grows naturally under controlled seawater flow conditions. The biofilm thickness and phycocyanin content are kept within a certain range, forming a natural absorption layer with gradient absorption properties. A slow-release nutrient supply system is also deployed to maintain a metabolic environment with a certain nitrogen-to-phosphorus ratio, inhibiting the colonization of sulfate-reducing bacteria.

[0040] (2) Configure laser shock parameters A laser with a specific range of pulse energy and pulse width parameters is used to control parameters such as spot diameter and overlap rate. A multi-source sensor network monitors the biofilm thickness distribution in real time, dynamically adjusting the pulse energy to a range of ±2 J. A natural seawater flow with a specific velocity is used as the confinement layer, and vortex guidance technology is used to optimize the propagation path of the plasma shock wave.

[0041] (3) Implementation of laser shot peening Spiral scanning was performed along the pile foundation axis, with a controlled scanning speed (10-15 mm / s) and a single-pass treatment width (40-60 mm). During the impact process, the biofilm's light absorption efficiency dynamically stabilized at 82%-85%, the surface residual compressive stress reached -320 MPa, and the microstructure exhibited a gradient nanocrystalline structure (grain size 20-150 nm).

[0042] As a specific embodiment, the present invention provides a process for extending the life of a deepwater pipeline weld reinforcement, comprising: (1) Preparation of a coordinated protection system A double-layer biofilm structure was constructed in the pipeline weld area, with an inner layer consisting of a Pseudoalteromonas membrane producing extracellular polymers (EPPseudoalteromonas) and an outer layer consisting of a photosynthetic cyanobacteria membrane. A biomimetic flow channel design was used to optimize the flow field, reducing the flow velocity in the weld area to 0.3 m / s and achieving a uniform biofilm coverage rate of ≥95%. Combined with the placement of zinc-based sacrificial anodes, an electrochemical-biological synergistic protective interface was formed.

[0043] (2) Dynamic laser parameter adaptation Configure the laser shock parameters of pulse energy and pulse width within a certain range, and control parameters such as spot diameter and overlap rate. Use the acoustic-optical feedback system to match the weld morphology in real time, and use the high peak power mode (peak power density 5~10 GW / cm 2 ), and the stress wave action time in the fusion line area is extended to 200 ns.

[0044] (3) Strengthening treatment and monitoring Repeated impacts were applied along the weld seam, with 50-70 minutes between passes to allow the biofilm to self-repair. After impact, the surface roughness (Ra) was reduced, and the residual stress field depth reached 1.2 mm. An integrated fiber optic sensing network monitored interfacial potential fluctuations in real time, dynamically compensating for microenvironmental variations ranging from -50 mV to +80 mV.

[0045] In a fourth aspect, the present invention provides an underwater component in service, comprising the aforementioned natural absorption layer for laser shot peening of the underwater component. The component in service includes deepwater pipelines, offshore wind power piles, anchor chains for cross-sea bridges, and supports for deep-sea drilling platforms.

[0046] One or more of the above technical solutions have the following advantages or beneficial effects: (1) The present invention discloses a natural absorption layer for laser shot peening of underwater components. The natural absorption layer is formed by in-situ inducing marine microbial communities to form a biofilm with gradient optical properties. Specifically, an algae-bacteria symbiotic system with light energy conversion and interface adhesion properties is selected to form a biofilm with gradient optical properties. A dynamic spectrum control strategy is adopted to activate the metabolic activity of target microorganisms with a specific wavelength combination of light to inhibit the colonization of corrosive bacteria.

[0047] (2) A life extension treatment process for underwater components based on natural absorption layer coupling laser pulses. By in-situ inducing marine microbial communities to form biofilms with gradient optical properties as natural absorption layers, the multi-physics field (light field refers to the photon flux in the 450-680 nm band, flow field refers to the seawater velocity distribution, and laser field refers to the plasma shock wave, and the three synergistically improve the energy transfer efficiency) coupling control technology is combined to achieve dynamic adaptation of laser peening parameters and biofilm state, and simultaneously complete surface enhancement and corrosion synergistic inhibition. The method first constructs algae-bacteria symbiotic biofilms on the surface of the component, uses dynamic spectral control to activate the metabolic activity of target microorganisms and inhibit the corrosive bacteria; optimizes the flow field distribution through biomimetic guide structures to maintain the uniformity of the biofilm, and integrates slow-release nutrient supply and periodic laser trimming to ensure the stability of the absorption layer. Secondly, based on the multi-source sensor network, the biofilm thickness and light absorption characteristics are monitored in real time, and a light energy conversion model is established to dynamically match the laser pulse energy, pulse width and scanning path. The propagation path of the plasma shock wave is controlled by combining the natural water flow constraint layer. Simultaneously, photosynthesis regulates the interfacial oxygen concentration gradient, and microbial metabolites passivate the metal surface, forming a composite system that combines physical strengthening with electrochemical protection. After impact treatment, the biofilm's natural degradation process is initiated. Non-contact detection and a digital twin model are combined to quantify the residual stress distribution and service performance evolution, ultimately achieving an eco-friendly underwater life extension treatment.

[0048] (3) The life extension treatment process provided by the present invention has the technical effects of zero chemical intervention, adaptive regulation, and corrosion-enhancement synergy. Specifically, the zero chemical intervention refers to the fact that the treatment process is completely dependent on in-situ ecological factors, does not require coating or pretreatment, and meets green manufacturing standards; the adaptive regulation refers to the fact that light-flow-laser multi-field coupling (photosynthesis regulates oxygen concentration gradient (light), natural water flow forms turbulent constraints (flow), and laser impact produces an enhancement effect (laser)) to achieve real-time matching of biofilm thickness, water flow rate, and laser energy; the corrosion-enhancement synergy refers to the fact that biological metabolism is combined with electrochemical protection to break through the bottleneck of traditional single technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The accompanying drawings, which constitute a part of the present invention, 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 improper limitations on the present invention.

[0050] Figure 1 shows a process flow chart in an embodiment of the present invention; DETAILED DESCRIPTION In the present invention, unless otherwise specified, other test materials and instruments and equipment are conventional test materials in this field and can be purchased through commercial channels.

[0051] Based on the many problems mentioned in the background technology when metal structural materials or components face underwater environments, there is an urgent need to provide a new protection system. Breakthroughs in the field of biofilm research provide new ideas for the construction of new protection systems. Specific microbial communities exhibit self-organized growth and light energy conversion characteristics. Studies have found that natural biofilms have excellent laser energy absorption capabilities and interface adaptive properties, and their metabolites can simultaneously achieve metal surface modification and corrosion inhibition. This biological-material synergistic mechanism has laid the foundation for the development of in-situ protection technology. At the same time, advances in multi-physical field coupling control technology have made it possible to monitor the state of biofilms in real time and dynamically match laser parameters, providing technical support for the construction of self-regulating surface treatment systems. Current marine equipment life extension technology shows a trend of deep multidisciplinary integration, and the cross-innovation of fluid dynamics, microbial engineering and advanced manufacturing technology continues to break through the boundaries of traditional technologies. By utilizing the natural elements of the marine environment to achieve energy transfer enhancement and ecological protection synergy, a new generation of environmentally adaptive surface treatment systems is being spawned. This technical route innovation has opened up an important way to solve the problem of long-term underwater protection. Therefore, the present invention provides a life extension treatment process for underwater in-service components based on natural absorption layer coupling laser pulses. During the process, the marine microbial community is induced in situ to form a biofilm with gradient optical properties as a natural absorption layer. Combined with multi-physical field coupling control technology, dynamic adaptation of laser peening parameters and biofilm state is achieved, and surface enhancement and corrosion synergistic inhibition are achieved simultaneously.

[0052] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0053] Example 1: Impact Life Extension of Offshore Wind Turbine Pile Foundation (1) Construction of in situ biofilm absorption layer A diatom-cyanobacteria mixed biofilm was induced on the surface of an offshore wind turbine foundation using a dynamic spectral control strategy (wavelength combination: alternating 450 nm blue light and 680 nm red light) and grown naturally for 21 days under controlled seawater flow rates of ≤0.8 m / s. The biofilm thickness reached 65±5 μm, and the phycocyanin content was stabilized at 1.2 mg / cm 2 , forming a natural absorption layer with gradient light absorption characteristics. A slow-release nutrient supply system is simultaneously deployed to maintain a metabolic environment with a nitrogen-to-phosphorus ratio of 12:1, inhibiting the colonization of sulfate-reducing bacteria.

[0054] (2) Configure laser shock parameters A Nd:YAG laser with a pulse energy of 25 J and a pulse width of 30 ns was used, with a spot diameter of 6 mm and an overlap rate of 80%. A multi-source sensing network was used to monitor the biofilm thickness distribution in real time, dynamically adjusting the pulse energy to a range of ±2 J. A 1.5 m / s natural seawater flow was used as the confinement layer, and vortex guidance technology was employed to optimize the plasma shock wave propagation path.

[0055] (3) Implementation of laser shot peening Spiral scanning was performed along the pile foundation axis at a speed of 12 mm / s, with a single pass width of 50 mm. During the impact process, the biofilm's light absorption efficiency dynamically stabilized at 82%-85%, the surface residual compressive stress reached -320 MPa, and the microstructure exhibited a gradient nanocrystalline structure (grain size 20-150 nm).

[0056] (4) Performance evaluation and operation and maintenance comparison After 240 days of testing in a marine environment, the corrosion rate dropped to 0.002 mm / a, and the area of ​​microbial fouling decreased by 76%. Compared with the traditional black paint coating process, the annual maintenance frequency was reduced from 6 to 2, the comprehensive operation and maintenance cost was reduced by 40%, and the fatigue life was increased to 1.5×10 7 load cycles.

[0057] Example 2: Deepwater Pipeline Weld Strengthening (1) Preparation of a coordinated protection system A double-layer biofilm structure was constructed in the weld area of ​​a submarine pipeline. The inner layer consisted of a 30 μm thick film of Pseudoalteromonas bacteria producing extracellular polymers (EPPseudoalteromonas), while the outer layer consisted of a 35 μm thick film of photosynthetic cyanobacteria. A biomimetic flow channel design was used to optimize the flow field, reducing the flow velocity in the weld area to 0.3 m / s and achieving a uniform biofilm coverage of ≥95%. Combined with a zinc-based sacrificial anode arrangement, this formed an electrochemical-biological synergistic protective interface.

[0058] (2) Dynamic laser parameter adaptation The laser shock parameters were configured with 25 J pulse energy and 30 ns pulse width, a spot diameter of 6 mm, and an overlap rate of 85%. The weld morphology was matched in real time through an acoustic-optical feedback system, and a high peak power mode (26 J high peak mode, peak power density 8 GW / cm) was used in the residual height area. 2 ), and the stress wave action time in the fusion line area is extended to 200 ns.

[0059] (3) Strengthening treatment and monitoring Three repeated impacts were applied along the weld seam, with a 60-minute interval between passes to allow for biofilm self-repair. After impact, the surface roughness Ra decreased from 12.6 μm to 3.2 μm, and the residual stress field depth reached 1.2 mm. An integrated fiber optic sensing network monitored interfacial potential fluctuations in real time, dynamically compensating for microenvironmental variations ranging from -50 mV to +80 mV.

[0060] (4) Long-term performance verification Combining accelerated fatigue testing with actual seawater verification, the fatigue life of welds exceeded 1×10 7 Cycle (API standard load spectrum). The microbial corrosion current density was reduced by 2 orders of magnitude, and the vessel maintained maintenance-free operation for 18 months at a water depth of 2,000 meters. The biofilm degradation products were tested and met ISO marine ecological safety standards.

[0061] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A natural absorption layer for laser shot peening of underwater components, characterized in that: The surface of the underwater in-service component is covered with a natural absorption layer, which is an in-situ biofilm obtained by directional induction and regulation based on the algae-bacteria symbiotic system; The algae-bacteria symbiotic system includes photosynthetic cyanobacteria and Pseudoalteromonas; Using a dynamic spectral control strategy, the biofilm grew naturally under controlled water flow conditions, with a biofilm thickness of 65±5 μm and a phycocyanin content stable at 1~2 mg / cm 2 , forming a natural absorption layer.

2. The natural absorption layer according to claim 1, characterized in that Alternate irradiation with 440-460 nm blue light and 670-690 nm red light; Preferably, the water flow rate is 0.3-0.8 m / s; Preferably, it is grown naturally for 15 to 25 days; Preferably, the biofilm has a double-layer structure, the inner layer is a Pseudoalteromonas membrane, and the outer layer is a photosynthetic cyanobacteria membrane, wherein the difference between the thickness of the outer layer and the thickness of the inner layer is 2-10 μm.

3. Use of the natural absorption layer for laser shot peening of underwater components according to claim 1 or 2 in the life extension treatment of in-service components in an aquatic environment.

4. A life extension treatment process for underwater in-service components, characterized in that: The following steps are involved: 1) constructing the natural absorption layer according to claim 1 or 2 on the surface of a target in-service component; 2) Construct a multi-source sensing network to monitor various parameters of the in situ biofilm in real time, establish an energy transfer model for light energy conversion efficiency, and achieve dynamic adaptation of laser parameters to the in situ biofilm state; 3) In the laser-impacted area, an electrochemical-fluid coupling control system is established using synergistic inhibition of microbial corrosion. This synergistic inhibition of microbial corrosion includes regulating the interfacial oxygen concentration gradient through photosynthesis, utilizing microbial secretion of antimicrobial and / or passivating substances, optimizing surface microstructure design, and combining intelligent response materials to achieve dynamic repair of damaged areas. 4) Conduct post-impact processing and evaluation.

5. The life extension process according to claim 1, characterized in that: Step 1) also includes: designing a bionic flow-guiding structure to optimize the local flow field distribution based on the fluid environment characteristics of the component surface; maintaining the ecological balance of the microbial community through a slow-release nutrient supply system, and implementing periodic laser trimming based on real-time monitoring data; Preferably, the slow-release nutrient supply system maintains a metabolic environment with a nitrogen-to-phosphorus ratio of 10 to 15:

1.

6. The life extension process according to claim 4, characterized in that: In step 2), the multi-source sensing network is a monitoring system including a fiber optic sensor, a multispectral imager, and an acoustic Doppler velocimeter; In step 2), the real-time monitoring of various parameters of the in-situ biofilm includes the thickness of the in-situ biofilm, light absorption characteristics and fluid parameters.

7. The life extension process according to claim 6, characterized in that: The establishment of the light energy conversion efficiency energy transfer model includes: adjusting the laser pulse energy, pulse width and spot distribution according to various parameters of the in-situ biofilm monitored in real time, designing a turbulent confinement layer in combination with natural water flow, and optimizing plasma expansion and shock wave propagation path; Preferably, the specific steps include: developing a dynamic parameter adjustment system to adaptively adjust the laser pulse energy, pulse width and spot distribution according to the in-situ biofilm state; when the sensor detects a thickness of <60 μm, the system switches to a 25-30 J high peak mode; when the thickness is >70 μm, the pulse width is extended to 35-40 ns; combining natural water flow to design a turbulence constraint layer, and using the bionic guide groove structure on the component surface to guide the water flow to form a directional vortex.

8. The life extension process according to claim 7, characterized in that: The laser pulse energy is 20-30 J, the pulse width is 20-40 ns, the spot diameter is 5-10 mm, and the overlap rate is 70-90%; Preferably, the turbulence constraint layer is designed based on natural water flow, and the flow rate of natural water flow is 1-5 m / s. Preferably, microorganisms are utilized to secrete antimicrobial substances and / or passivating substances, and the microorganisms are beneficial microorganisms, including photosynthetic cyanobacteria that secrete antimicrobial peptides and Pseudoalteromonas that secrete extracellular polymers.

9. The life extension process according to claim 4, characterized in that: In step 4), the specific steps include: initiating the natural degradation process of the biofilm, in-situ monitoring and tracking the film peeling process and the environmental migration path of the degradation products; using non-contact detection technology to analyze the residual stress distribution, micromorphology and sub-surface defect evolution of the component surface, and quantifying the effect of laser shock on material performance improvement; deploying a long-term monitoring system in a simulated and real marine environment, and constructing a digital twin model to invert the mapping relationship between process parameters and service behavior; Preferably, after the light and nutrient supply are terminated, the apoptosis of the algae triggers the release of intracellular enzymes, initiating the natural degradation process of the biofilm; Preferably, in situ monitoring is achieved by fluorescent labeling; Preferably, the non-contact detection technology includes X-ray diffractometer, confocal microscope and ultrasonic phased array.

10. An underwater in-service component, characterized in that: The invention comprises the natural absorption layer for laser shot peening of underwater components as claimed in claim 1 or 2.

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