WO2024046430A1 - 一种钢筋混凝土结构损伤定量监测方法及系统 - Google Patents

一种钢筋混凝土结构损伤定量监测方法及系统 Download PDF

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WO2024046430A1
WO2024046430A1 PCT/CN2023/116214 CN2023116214W WO2024046430A1 WO 2024046430 A1 WO2024046430 A1 WO 2024046430A1 CN 2023116214 W CN2023116214 W CN 2023116214W WO 2024046430 A1 WO2024046430 A1 WO 2024046430A1
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section
time
fiber
concrete
steel
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PCT/CN2023/116214
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English (en)
French (fr)
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周英武
叶增辉
黄晓旭
邢锋
李宗军
朱忠锋
郭孟环
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深圳大学
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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/10—Geometric CAD
    • G06F30/13—Architectural design, e.g. computer-aided architectural design [CAAD] related to design of buildings, bridges, landscapes, production plants or roads
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C3/00—Structural elongated elements designed for load-supporting
    • E04C3/02—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces
    • E04C3/20—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of concrete or other stone-like material, e.g. with reinforcements or tensioning members
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/14—Force analysis or force optimisation, e.g. static or dynamic forces

Definitions

  • the invention relates to the technical field of civil engineering, and in particular to a quantitative monitoring method and system for damage to reinforced concrete structures.
  • Reinforced concrete (RC) structures are strong, durable, have good fire resistance, and have low construction costs. They are currently a widely used structural form. Many important infrastructures use reinforced concrete structures, such as ports, bridges, airports, etc. Reinforced concrete structures may be subjected to extreme loads such as earthquakes, impacts, explosions, and typhoons many times during the design basis period. Real-time quantitative damage monitoring of important reinforced concrete structures helps to accurately judge the performance degradation of the structure and provides reference for emergency repairs and structural repairs. Therefore, it is necessary and important to quantitatively monitor and evaluate structural damage caused by various complex loads.
  • Damage to beams and columns under load is divided into superficial damage and internal damage.
  • the extent of superficial damage can be determined with the naked eye, but internal damage is difficult to distinguish with the naked eye.
  • the cross-section damage has uncertainty in the damage degree and damage distribution.
  • Distributed optical fiber sensors have huge application potential in structural health monitoring due to their characteristics of light weight, high accuracy, high sensitivity, and anti-interference. However, it can only detect the strain of specific components of the structure, and cannot quantitatively monitor and evaluate the damage of the structure.
  • the purpose of the present invention is to provide a quantitative monitoring method and system for damage to reinforced concrete structures to solve the problem that structural damage analysis methods in the prior art cannot quantitatively monitor and evaluate structural damage.
  • the present invention provides the following solutions:
  • a quantitative monitoring method for reinforced concrete structure damage including:
  • the section design parameters include geometric parameters and material performance parameters; the geometric parameters include section width, section height, section equivalent height, protective layer thickness and steel bar area; the material performance parameters include concrete compression peak stress, concrete initial Tangent modulus and initial tangent modulus of steel bars;
  • a cross-section analysis model is established according to the cross-section design parameters;
  • the cross-section analysis model includes a concrete damage stress-strain relationship model and a steel bar damage stress-strain relationship model;
  • the optical fiber strain signal is input into the cross-section analysis model to obtain the damage index and bending moment-curvature curve of each cross-section.
  • optical fiber strain signal into the cross-section analysis model to obtain the damage index and bending moment-curvature curve of each cross-section, which specifically includes:
  • the strain distribution of the steel fibers in the x-th section at time t use the steel damage stress-strain relationship model to calculate the stress distribution and damage index of the steel fibers in the x-th section at time t; the stress distribution and damage index of the x-th section at time t are calculated
  • the strain distribution of the steel fiber includes the strain distribution of the tensile steel fiber in the x-th section at time t and the strain distribution of the compression steel fiber in the x-th section at time t;
  • ⁇ Nx(t) is the resultant force of the axial force
  • D ci,x ( ⁇ ci,x (t)) is the damage index of the i-th concrete fiber in the x-th section at time t
  • D s ,x ( ⁇ sc,x (t)) is the damage index of the compression steel fiber of the x-th section at time t
  • D s,x ( ⁇ s,x (t)) is the tensile strength of the x-th section at time t Damage index of steel fiber
  • b is the cross-section width
  • h is the cross-section height
  • a s is the area of the tensile steel fiber
  • a s ' is the area of the compressed steel fiber
  • ⁇ s,x ( ⁇ sc,x (t)) is the stress distribution of the x-th section of
  • the calculation of the damage index and bending moment-curvature curve of the x-th section at time t specifically includes:
  • D ci,x ( ⁇ ci,x (t)) is the damage index of the i-th concrete fiber in the x-th section at time t
  • D s,x ( ⁇ sc,x (t)) is the damage index of the x-th section at time t.
  • Damage index of compression steel fiber D s,x ( ⁇ s,x (t)) is the damage index of tension steel fiber in the x-th section at time t; h is the section height; A s is the area of tension steel fiber ; A s ' is the area of compressed steel fiber; ⁇ s,x ( ⁇ sc,x (t)) is the stress distribution of compressed steel fiber in the x-th section at time t; ⁇ s,x ( ⁇ s,x ( t)) is the strain distribution of the tensile steel fiber in the x-th section at time t; ⁇ ci,x ( ⁇ ci,x (t)) is the stress of the i-th concrete fiber in the x-th section at time t; E 0 is the initial tangent modulus of concrete; d' is the thickness of the protective layer; E s is the initial tangent modulus of steel; A c,i is the area of the i-th concrete fiber; n(x) is
  • the bending moment-curvature curve is obtained.
  • a quantitative monitoring system for reinforced concrete structure damage including:
  • the data acquisition module is used to obtain the optical fiber strain signal and cross-sectional design parameters of the longitudinal tension steel bars of the reinforced concrete beam;
  • the cross-sectional design parameters include geometric parameters and material performance parameters;
  • the geometric parameters include cross-sectional width, cross-sectional height, cross-section, etc. Effective height, protective layer thickness and steel bar area;
  • the material performance parameters include concrete compressive peak stress, concrete initial tangent modulus and steel bar initial tangent modulus;
  • a model building module configured to establish a cross-section analysis model according to the cross-section design parameters;
  • the cross-section analysis model includes a concrete damage stress-strain relationship model and a steel bar damage stress-strain relationship model;
  • a calculation module is used to input the optical fiber strain signal into the cross-section analysis model to obtain the damage index and bending moment-curvature curve of each cross-section.
  • the computing module includes:
  • Neutral axis hypothesis unit used to set the neutral axis position of the x-th section at time t as y 0,x (t);
  • a strain calculation unit used to calculate the strain distribution of the concrete fibers in the x-th section at time t and the strain distribution of the compressed steel fibers in the x-th section at time t based on the curvature;
  • a concrete stress calculation unit configured to calculate the stress distribution and damage index of the concrete fiber at the xth section at time t based on the strain distribution of the concrete fiber at the xth section at time t, using the concrete damage stress-strain relationship model;
  • the steel stress calculation unit is used to calculate the stress distribution and damage index of the steel fibers in the xth section at time t based on the strain distribution of the steel fibers in the xth section at time t, using the steel damage stress-strain relationship model;
  • the strain distribution of the steel fibers in the x-th section at time t includes the strain distribution of the tension steel fibers in the x-th section at time t and the strain distribution of the compression steel fibers in the x-th section at time t;
  • the resultant force calculation unit is used to calculate the resultant force of the axial force based on the stress distribution and damage index of the concrete fiber of the xth section at time t and the stress distribution and damage index of the steel fiber of the xth section at time t;
  • a judgment unit used to judge whether the resultant force of the axial force is zero;
  • the first execution unit is used to calculate the damage index and bending moment-curvature curve of the x-th section at time t and output them if the resultant force of the axial force is zero;
  • the second execution unit is used to return to the step of "Suppose the neutral axis position of the x-th section curvature at time t is y 0,x (t)" if the resultant force of the axial force is not zero.
  • the resultant force calculation unit includes:
  • the first execution unit includes:
  • D ci,x ( ⁇ ci,x (t)) is the damage index of the i-th concrete fiber in the x-th section at time t
  • D s,x ( ⁇ sc,x (t)) is the damage index of the x-th section at time t.
  • Damage index of compression steel fiber D s,x ( ⁇ s,x (t)) is the damage index of tension steel fiber in the x-th section at time t; h is the section height; A s is the area of tension steel fiber ; A s ' is the area of compressed steel fiber; ⁇ s,x ( ⁇ sc,x (t)) is the stress distribution of compressed steel fiber in the x-th section at time t; ⁇ s,x ( ⁇ s,x ( t)) is the strain distribution of the tensile steel fiber in the x-th section at time t; ⁇ ci,x ( ⁇ ci,x (t)) is the stress of the i-th concrete fiber in the x-th section at time t; E 0 is the initial tangent modulus of concrete; d' is the thickness of the protective layer; E s is the initial tangent modulus of steel; A c,i is the area of the i-th concrete fiber; n(x) is
  • the bending moment calculation subunit is used to calculate the sum of the products of the axial force of each concrete fiber and the distance from the center of the concrete fiber to the neutral axis y 0, x (t), the axial force of each steel fiber and the distance from the center of the steel fiber to the neutral axis.
  • a curve drawing subunit is used to draw the bending moment-curvature curve according to the bending moment and the curvature.
  • the present invention discloses the following technical effects:
  • the present invention arranges distributed optical fiber sensors on the tension steel bars of reinforced concrete beams and inputs the optical fiber strain signals collected by the distributed optical fiber sensors into the established cross-section analysis model to calculate the damage index and damage mechanical properties of each cross-section.
  • the present invention combines distributed optical fiber sensing technology with the damage assessment theory of cross-sectional analysis to realize the inversion of locally monitored strains into damage indicators and damage mechanical properties corresponding to each cross-section, and to realize quantitative monitoring of the damaged cross-section.
  • Figure 1 is a flow chart of a quantitative monitoring method for reinforced concrete structure damage provided by the present invention
  • Figure 2 is a schematic diagram of the cross-sectional unit division provided by the present invention.
  • Figure 3 is a schematic diagram of the concrete fiber division provided by the present invention.
  • Figure 4 is a flow chart of using the cross-section analysis model to calculate the damage index and bending moment-curvature curve of the cross-section in practical applications;
  • Figure 5 is a structural diagram of a reinforced concrete structure damage quantitative monitoring system provided by the present invention.
  • the purpose of the present invention is to provide a quantitative monitoring method and system for damage to reinforced concrete structures to solve the problem that structural damage analysis methods in the prior art cannot quantitatively monitor and evaluate structural damage.
  • the main problem solved by the present invention is to quantitatively monitor the performance of damaged sections, thereby evaluating the degree of damage (rebar damage index, concrete damage index, section damage index) and mechanical properties (load , deflection). Therefore, it is proposed to arrange distributed optical fiber sensors on the tension steel bars of reinforced concrete beams, and input the strain data collected by the distributed optical fiber sensors into the cross-section analysis program to calculate the damage index and damage mechanical properties of each section, providing a Methods for quantitative monitoring of damage to reinforced concrete structures.
  • This invention is based on the longitudinal tensile steel strain signal collected by distributed optical fibers and the cross-sectional analysis program written in Matlab, and can quantitatively monitor the damage state of the cross-section of interest.
  • the monitored local strain signals can be used to back-calculate the damage factors and mechanical properties corresponding to each damaged section, quantitatively analyze the degradation of the overall performance of the structure, and evaluate the attenuation and residual performance of the overall performance of the component.
  • Figure 1 is a flow chart of a quantitative monitoring method for reinforced concrete structure damage provided by the present invention. As shown in Figure 1, the method includes:
  • Step 101 Obtain the optical fiber strain signal and cross-sectional design parameters of the longitudinal tension steel of the reinforced concrete beam.
  • the section design parameters include geometric parameters and material performance parameters; the geometric parameters include section width, section height, section equivalent height, protective layer thickness and steel bar area; the material performance parameters include concrete compression peak stress, concrete initial Tangent modulus and initial tangent modulus of steel bars.
  • distributed optical fibers are arranged in the longitudinal tension steel bars of newly constructed reinforced concrete beams in advance, and the optical fiber strain signals are collected in real time.
  • Step 102 Establish a cross-sectional analysis model according to the cross-sectional design parameters.
  • the cross-section analysis model includes a concrete damage stress-strain relationship model and a steel bar damage stress-strain relationship model.
  • the cross-sectional analysis program is an important part of the present invention, specifically as follows:
  • the cross-section limit state is defined as the outermost concrete fiber in the compression zone reaching the ultimate compressive strain.
  • the reinforced concrete beam is divided into m section units along the length direction X-axis. As shown in Figure 2, the section units have the same number as the distributed optical fiber strain measuring points. Divide each section into n fibers along the y-axis in the height direction, as shown in Figure 3.
  • Step 103 Input the optical fiber strain signal into the cross-section analysis model to obtain the damage index and bending moment-curvature curve of each cross-section.
  • Input section design parameters such as geometric parameters (such as section width b, section height h, section equivalent height, protective layer thickness, steel bar area, etc.), material performance parameters (concrete compressive peak stress, concrete initial tangent modulus, The initial tangent modulus of the steel bar, etc.)) and the strain distribution of the x-th section tensile steel fiber (expressed as ⁇ s, x (t), that is, the fiber strain signal) collected by the distributed optical fiber at time t are transferred to the cross-section analysis model.
  • the subscript x is used to represent the section number.
  • S6 According to the strain distribution of the steel fibers in the x-th section at time t, use the steel damage stress-strain relationship model to calculate the stress distribution and damage index of the steel fibers in the x-th section at time t; the x-th section at time t
  • the strain distribution of the cross-section steel fibers includes the strain distribution of the tensile steel fibers in the x-th cross-section at time t and the strain distribution of the compression steel fibers in the x-th cross-section at time t.
  • strains of each concrete and steel fiber in the x-th section at time t are substituted into the concrete damage stress-strain relationship model and the steel damage stress-strain relationship model to calculate the stress distribution and damage index of each concrete and steel fiber on the section at the corresponding time.
  • the stress of the i-th concrete fiber in the x-th section at time t can be expressed as ⁇ ci,x ( ⁇ ci,x (t)), and the tensile and compression steel fiber stresses in the x-th section at time t can be expressed as: ⁇ s,x ( ⁇ s,x (t)), ⁇ s,x ( ⁇ sc,x (t)); the damage index of the i-th concrete fiber in the x-th section at time t can be expressed as D ci,x ( ⁇ ci,x (t));
  • the damage indexes of the tensile and compressive steel fibers of the x-th section at time t can be expressed as: D s,x ( ⁇ s,x (t)), D s,x ( ⁇ sc,x (t)).
  • the concrete damage stress-strain relationship in the cross-section analysis program adopts the concrete uniaxial damage stress-strain relationship given in the "Design Code for Concrete Structures" (GB 50010-2010), and the i-th concrete fiber in the x-th section at time t is calculated. stress.
  • ⁇ ci,x ( ⁇ ci,x (t)) (1-D ci,x ( ⁇ ci,x (t)))E 0 ⁇ ci,x (t), E 0 initial tangent modulus of concrete .
  • f c is the peak stress of unconstrained concrete
  • ⁇ 0 is the peak strain corresponding to the peak stress of unconstrained concrete
  • ⁇ c is the parameter value of the declining section of the uniaxial compressive stress-strain curve.
  • ⁇ t is the parameter value of the descending section of the uniaxial tensile stress-strain curve, is the uniaxial tensile strength of concrete, ⁇ t is Corresponding peak tensile strain of concrete.
  • the stress ⁇ s,x ( ⁇ s,x (t)) (1-D s,x ( ⁇ s,x (t)))E s ⁇ s,x ( t); damage index
  • E s is the initial tangent modulus of the steel bar
  • ⁇ y is the yield strain of the steel bar.
  • ⁇ Nx(t) is the resultant force of the axial force
  • b is the cross-sectional width
  • h is the cross-sectional height degree
  • a s is the fiber area of the tension steel bar
  • a s ' is the fiber area of the compression steel bar
  • n(x) is the number of concrete fibers in the x-th section.
  • D ci,x ( ⁇ ci,x (t)) is the damage index of the i-th concrete fiber in the x-th section at time t
  • D s,x ( ⁇ sc,x (t)) is the damage index of the x-th section at time t.
  • D s,x ( ⁇ s,x (t)) is the damage index of tension steel fibers in the x-th section at time t
  • E 0 is the initial tangent modulus of concrete
  • d' is protection layer thickness
  • E s is the initial tangent modulus of the steel bar
  • a c,i is the area of the i-th concrete fiber
  • n(x) is the number of concrete fibers in the x-th section.
  • A, B, C, A', B', and C' are intermediate variables for simplified calculation and have no specific meaning.
  • the bending moment-curvature curve is drawn.
  • Repeating S1-S10 can calculate the bending moment-curvature curve and damage index of all sections (m sections).
  • the invention combines distributed optical fiber sensing technology and damage section analysis method, and can invert the collected strain signal to the damage factor and mechanical properties of the section of interest. It can not only display the stress, strain, and damage variables of concrete fibers and steel fibers in the section, but also quantitatively evaluate the mechanical properties and damage indicators of the section.
  • the sensors of this invention are simple to arrange, and only need to arrange distributed optical fiber sensors on the longitudinal tension steel bars to quantitatively obtain the stress state and damage indicators of each section.
  • the damage indicators and mechanical properties of key components of the reinforced concrete structure during service can be monitored in real time, and then the safety of the structure can be evaluated. performance, providing guarantee and guidance for structural maintenance and repair.
  • distributed optical fiber sensors can be arranged in longitudinal stress-bearing components of beams and columns, such as steel bars, FRP bars, steel-FRP continuous fiber bars, steel plates, etc.
  • the premise of this method is to obtain the damage stress-strain relationship of the material, which can be replaced according to the material type of the structure.
  • This method is not limited by the cross-sectional shape of the structure, which can be either a square or a circular cross-section.
  • the invention also provides a reinforced concrete structure damage quantitative monitoring system, as shown in Figure 5, including:
  • the data acquisition module 501 is used to acquire the optical fiber strain signal and cross-sectional design parameters of the longitudinal tension steel bars of the reinforced concrete beam;
  • the cross-sectional design parameters include geometric parameters and material performance parameters;
  • the geometric parameters include section width, section height, section equivalent height, protective layer thickness and steel bar area;
  • the material performance parameters include concrete compressive peak stress, concrete initial tangent modulus and steel bar initial tangent modulus.
  • the model building module 502 is used to establish a cross-section analysis model according to the cross-section design parameters; the cross-section analysis model includes a concrete damage stress-strain relationship model and a steel bar damage stress-strain relationship model.
  • the calculation module 503 is used to input the optical fiber strain signal into the cross-section analysis model to obtain the damage index and bending moment-curvature curve of each cross-section.
  • calculation module 503 includes:
  • the neutral axis assumption unit is used to set the neutral axis position of the x-th section at time t to be y 0,x (t).
  • ⁇ x (t) is the curvature of the x-th section at time t
  • ⁇ s, x (t) is the optical fiber strain signal
  • d is the equivalent height of the section.
  • a strain calculation unit is used to calculate the strain distribution of the concrete fibers in the x-th section at time t and the strain distribution of the compressed steel fibers in the x-th section at time t based on the curvature.
  • the concrete stress calculation unit is used to calculate the stress distribution and damage index of the concrete fiber at the xth section at time t based on the strain distribution of the concrete fiber at the xth section at time t, using the concrete damage stress-strain relationship model.
  • the steel stress calculation unit is used to calculate the stress distribution and damage index of the steel fibers in the xth section at time t based on the strain distribution of the steel fibers in the xth section at time t, using the steel damage stress-strain relationship model.
  • the strain distribution of the x-th cross-section steel fiber at time t includes the strain distribution of the tensile steel fiber fiber at the x-th cross-section at time t and the strain distribution of the compression steel fiber fiber at the x-th cross-section at time t.
  • the resultant force calculation unit is used to calculate the resultant force of the axial force based on the stress distribution and damage index of the concrete fibers in the xth section at time t and the stress distribution and damage index of the steel fibers in the xth section at time t.
  • a judgment unit is used to judge whether the resultant force of the axial force is zero.
  • the first execution unit is used to calculate and output the damage index and bending moment-curvature curve of the x-th section at time t if the resultant force of the axial force is zero.
  • the second execution unit is used to return to the step of "Suppose the neutral axis position of the x-th section curvature at time t is y 0,x (t)" if the resultant force of the axial force is not zero.
  • the resultant force calculation unit includes:
  • the first execution unit includes:
  • D ci,x ( ⁇ ci,x (t)) is the damage index of the i-th concrete fiber in the x-th section at time t
  • D s,x ( ⁇ sc,x (t)) is the damage index of the x-th section at time t.
  • D s,x ( ⁇ s,x (t)) is the damage index of tension steel fibers in the x-th section at time t
  • E 0 is the initial tangent modulus of concrete
  • d' is the thickness of the protective layer
  • E s is the initial tangent modulus of steel bars
  • a c,i is the area of the i-th concrete fiber
  • n(x) is the concrete fiber in the x-th section quantity.
  • the bending moment calculation subunit is used to calculate the sum of the products of the axial force of each concrete fiber and the distance from the center of the concrete fiber to the neutral axis y 0, x (t), the axial force of each steel fiber and the distance from the center of the steel fiber to the neutral axis.
  • Msx(t) is the bending moment of the x-th cross-section steel fiber at time t
  • Msx(t) (1-D s,x ( ⁇ s,x (t))) ⁇ s,x ( ⁇ s,x (t) ))A s (d-h+y 0,x (t))+(1-D s,x ( ⁇ sc,x (t))) ⁇ s,x ( ⁇ sc,x (t))A′ s (hd′-y 0,x (t)).
  • a curve drawing subunit is used to draw the bending moment-curvature curve according to the bending moment and the curvature.

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Abstract

本发明涉及一种钢筋混凝土结构损伤定量监测方法及系统，属于土木工程技术领域。方法包括：获取钢筋混凝土梁的纵向受拉钢筋的光纤应变信号和截面设计参数(101)；截面设计参数包括几何参数和材料性能参数；几何参数包括截面宽度、截面高度、截面等效高度、保护层厚度和钢筋面积；材料性能参数包括混凝土受压峰值应力、混凝土初始切线模量和钢筋初始切线模量；根据截面设计参数建立截面分析模型(102)；截面分析模型包括混凝土损伤应力-应变关系模型和钢筋损伤应力-应变关系模型；将光纤应变信号输入截面分析模型，得到各个截面的损伤指标和弯矩-曲率曲线(103)。本发明实现了对损伤截面进行定量监测。

Description

一种钢筋混凝土结构损伤定量监测方法及系统
本申请要求于2022年08月31日提交中国专利局、申请号为202211053057.9、发明名称为“一种钢筋混凝土结构损伤定量监测方法及系统”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本发明涉及土木工程技术领域，特别是涉及一种钢筋混凝土结构损伤定量监测方法及系统。
背景技术
钢筋混凝土(RC)结构具有坚固、耐久、耐火性能好、建造成本低等特点，是目前运用较广泛的一种结构形式。许多重要基础设施都是采用钢筋混凝土结构，如港口、桥梁、机场等。钢筋混凝土结构在设计基准期内可能会多次遭受地震、撞击、爆炸、台风等极端荷载。对重要的钢筋混凝土结构进行实时损伤定量监测，有助于对于结构的性能退化有准确的判断，为抢修和结构修复提供参考。因此对各种复杂荷载导致的结构损伤进行定量监测及评估具有一定的必要性和重要意义。
荷载作用下梁柱的损伤分为表观损伤和内部损伤，表观损伤可以使用肉眼判定损伤的程度，但是内部损伤肉眼难以分辨。同时由于荷载的不确定性，截面损伤具有损伤程度不确定性和损伤分布不确定性。目前对于截面损伤定量分析已有成熟的理论，主要通过截面分析方法对截面损伤进行定量分析。分布式光纤传感器由于具有质量轻、精度高、灵敏度高、抗干扰等特点在结构健康监测中具有巨大的应用潜力。但是其只能对结构特定部件的应变进行检测，无法对结构的损伤进行定量监测和评估。
发明内容
本发明的目的是提供一种钢筋混凝土结构损伤定量监测方法及系统，以解决现有技术中的结构损伤分析方法无法对结构的损伤进行定量监测和评估的问题。
为实现上述目的，本发明提供了如下方案：
一种钢筋混凝土结构损伤定量监测方法，包括：
获取钢筋混凝土梁的纵向受拉钢筋的光纤应变信号和截面设计参数； 所述截面设计参数包括几何参数和材料性能参数；所述几何参数包括截面宽度、截面高度、截面等效高度、保护层厚度和钢筋面积；所述材料性能参数包括混凝土受压峰值应力、混凝土初始切线模量和钢筋初始切线模量；
根据所述截面设计参数建立截面分析模型；所述截面分析模型包括混凝土损伤应力-应变关系模型和钢筋损伤应力-应变关系模型；
将所述光纤应变信号输入所述截面分析模型，得到各个截面的损伤指标和弯矩-曲率曲线。
可选地，将所述光纤应变信号输入所述截面分析模型，得到各个截面的损伤指标和弯矩-曲率曲线，具体包括：
设t时刻第x个截面的中和轴位置为y0,x(t)；
根据所述截面设计参数、所述光纤应变信号和所述中和轴位置，利用公式φx(t)＝εs，x(t)/(y0，x(t)-d)计算t时刻第x个截面的曲率；其中，φx(t)为t时刻第x个截面的曲率；εs，x(t)为光纤应变信号；d为截面等效高度；
根据所述曲率计算t时刻第x个截面的混凝土纤维的应变分布和t时刻第x个截面的受压钢筋纤维的应变分布；
根据所述t时刻第x个截面的混凝土纤维的应变分布，利用所述混凝土损伤应力-应变关系模型计算t时刻第x个截面的混凝土纤维的应力分布和损伤指标；
根据t时刻第x个截面的钢筋纤维的应变分布，利用所述钢筋损伤应力-应变关系模型计算t时刻第x个截面的钢筋纤维的应力分布和损伤指标；所述t时刻第x个截面的钢筋纤维的应变分布包括t时刻第x个截面的受拉钢筋纤维的应变分布和t时刻第x个截面的受压钢筋纤维的应变分布；
根据所述t时刻第x个截面的混凝土纤维的应力分布和损伤指标以及所述t时刻第x个截面的钢筋纤维的应力分布和损伤指标计算轴力的合力；
判断所述轴力的合力是否为零；
若所述轴力的合力为零，则计算t时刻第x个截面的损伤指标和弯矩-曲率曲线并输出；
若所述轴力的合力不为零，则返回“设t时刻第x个截面曲率中和轴位置为y0,x(t)”的步骤。
可选地，根据所述t时刻第x个截面的混凝土纤维的应力分布和损伤指标以及所述t时刻第x个截面的钢筋纤维的应力分布和损伤指标计算轴力的合力，具体包括：
利用公式 计算轴力的合力；其中，∑Nx(t)为轴力的合力；Dci,x(εci,x(t))为t时刻第x个截面第i根混凝土纤维的损伤指标、Ds,x(εsc,x(t))为t时刻第x个截面的受压钢筋纤维的损伤指标；Ds,x(εs,x(t))为t时刻第x个截面的受拉钢筋纤维的损伤指标；Ac,i＝(bh/n(x))为第i个混凝土纤维的面积；b为截面宽度；h为截面高度；As为受拉钢筋纤维面积；As’为受压钢筋纤维面积；σs,x(εsc,x(t))为t时刻第x个截面的受压钢筋纤维的应力分布；σs,x(εs,x(t))为t时刻第x个截面的受拉钢筋纤维的应变分布；σci,x(εci,x(t))为t时刻第x个截面中第i个混凝土纤维的应力；n(x)是第x个截面中混凝土纤维的数量。
可选地，所述计算t时刻第x个截面的损伤指标和弯矩-曲率曲线，具体包括：
利用公式计算t时刻第x个截面的损伤指标；其中， A'＝E0Ac,iyi,x(t)2+EsAs(d-h+y0,x(t))2+EsA's(h-d'-y0,x(t))2、B′＝E0Ac,iyi,x(t)+EsAs(d-h+y0,x(t))+EsA′s(h-d′-y0,x(t))、
Dci,x(εci,x(t))为t时刻第x个截面第i根混凝土纤维的损伤指标、Ds,x(εsc,x(t))为t时刻第x个截面的受压钢筋纤维的损伤指标；Ds,x(εs,x(t))为t时刻第x个截面的受拉钢筋纤维的损伤指标；h为截面高度；As为受拉钢筋纤维面积；As’为受压钢筋纤维面积；σs,x(εsc,x(t))为t时刻第x个截面的受压钢筋纤维的应力分布；σs,x(εs,x(t))为t时刻第x个截面的受拉钢筋纤维的应变分布；σci,x(εci,x(t))为t时刻第x个截面中第i个混凝土纤维的应力；E0为混凝土初始切线模量；d’为保护层厚度；Es为钢筋初始切线模量；Ac,i为第i根混凝土纤维的面积；n(x)是第x个截面中混凝土纤维的数量；
根据各混凝土纤维的轴力与混凝土纤维中心到中和轴y0，x(t)的距离的乘积之和、各钢筋纤维的轴力与钢筋纤维中心到中和轴y0，x(t)的距离的乘积之和计算第x个截面的弯矩Mx(t)＝Mcx(t)+Msx(t)；其中，Mcx(t)为t时刻第x个截面混凝土纤维的弯矩， yi，x(t)为t时刻第x个截面中第i个混凝土纤维中心到中和轴的距离；Msx(t)为t时刻第x个截面钢筋纤维的弯矩，Msx(t)＝(1-Ds,x(εs,x(t)))σs,x(εs,x(t))As(d-h+y0,x(t))+(1-Ds,x(εsc,x(t)))σs,x(εsc,x(t))A's(h-d'-y0,x(t))；
根据所述弯矩和所述曲率，得到所述弯矩-曲率曲线。
一种钢筋混凝土结构损伤定量监测系统，包括：
数据获取模块，用于获取钢筋混凝土梁的纵向受拉钢筋的光纤应变信号和截面设计参数；所述截面设计参数包括几何参数和材料性能参数；所述几何参数包括截面宽度、截面高度、截面等效高度、保护层厚度和钢筋面积；所述材料性能参数包括混凝土受压峰值应力、混凝土初始切线模量和钢筋初始切线模量；
模型建立模块，用于根据所述截面设计参数建立截面分析模型；所述截面分析模型包括混凝土损伤应力-应变关系模型和钢筋损伤应力-应变关系模型；
计算模块，用于将所述光纤应变信号输入所述截面分析模型，得到各个截面的损伤指标和弯矩-曲率曲线。
可选地，所述计算模块，包括：
中和轴假设单元，用于设t时刻第x个截面的中和轴位置为y0,x(t)；
曲率计算单元，用于根据所述截面设计参数、所述光纤应变信号和所述中和轴位置，利用公式φx(t)＝εs，x(t)/(y0，x(t)-d)计算t时刻第x个截面的曲率；其中，φx(t)为t时刻第x个截面的曲率，εs，x(t)为光纤应变信号，d为截面等效高度；
应变计算单元，用于根据所述曲率计算t时刻第x个截面的混凝土纤维的应变分布和t时刻第x个截面的受压钢筋纤维的应变分布；
混凝土应力计算单元，用于根据所述t时刻第x个截面的混凝土纤维的应变分布，利用所述混凝土损伤应力-应变关系模型计算t时刻第x个截面的混凝土纤维的应力分布和损伤指标；
钢筋应力计算单元，用于根据t时刻第x个截面的钢筋纤维的应变分布，利用所述钢筋损伤应力-应变关系模型计算t时刻第x个截面的钢筋纤维的应力分布和损伤指标；所述t时刻第x个截面的钢筋纤维的应变分布包括t时刻第x个截面的受拉钢筋纤维的应变分布和t时刻第x个截面的受压钢筋纤维的应变分布；
合力计算单元，用于根据所述t时刻第x个截面的混凝土纤维的应力分布和损伤指标以及所述t时刻第x个截面的钢筋纤维的应力分布和损伤指标计算轴力的合力；
判断单元，用于判断所述轴力的合力是否为零；
第一执行单元，用于若所述轴力的合力为零，则计算t时刻第x个截面的损伤指标和弯矩-曲率曲线并输出；
第二执行单元，用于若所述轴力的合力不为零，则返回“设t时刻第x个截面曲率中和轴位置为y0,x(t)”的步骤。
可选地，所述合力计算单元，包括：
合力计算子单元，用于利用公式 计算轴力的合力；其中，∑Nx(t)为轴力的合 力；Dci,x(εci,x(t))为t时刻第x个截面第i根混凝土纤维的损伤指标；Ds,x(εsc,x(t))为t时刻第x个截面的受压钢筋纤维的损伤指标；Ds,x(εs,x(t))为t时刻第x个截面的受拉钢筋纤维的损伤指标；Ac,i＝(bh/n(x))为第i个混凝土纤维的面积；b为截面宽度；h为截面高度；As为受拉钢筋纤维面积；As’为受压钢筋纤维面积；σs,x(εsc,x(t))为t时刻第x个截面的受压钢筋纤维的应力分布；σs,x(εs,x(t))为t时刻第x个截面的受拉钢筋纤维的应变分布；σci,x(εci,x(t))为t时刻第x个截面中第i个混凝土纤维的应力；n(x)是第x个截面中混凝土纤维的数量。
可选地，所述第一执行单元，包括：
损伤指标计算子单元，用于利用公式计算t时刻第x个截面的损伤指标；其中， A'＝E0Ac,iyi,x(t)2+EsAs(d-h+y0,x(t))2+EsA's(h-d'-y0,x(t))2、B'＝E0Ac,iyi,x(t)+EsAs(d-h+y0,x(t))+EsA's(h-d'-y0,x(t))、
Dci,x(εci,x(t))为t时刻第x个截面第i根混凝土纤维的损伤指标、Ds,x(εsc,x(t))为t时刻第x个截面的受压钢筋纤维的损伤指标；Ds,x(εs,x(t))为t时刻第x个截面的受拉钢筋纤维的损伤指标；h为截面高度；As为受拉钢筋纤维面积；As’为受压钢筋纤维面积；σs,x(εsc,x(t))为t时刻第x个截面的受压钢筋纤维的应力分布；σs,x(εs,x(t))为t时刻第x个截面的受拉钢筋纤维的应变分布；σci,x(εci,x(t))为t时刻第x个截面中第i个混凝土纤维的应力；E0为混凝土初始切线模量；d’为保护层厚度；Es为钢筋初始切线模量；Ac,i为第i根混凝土纤维的面积；n(x)是第x个截面 中混凝土纤维的数量；
弯矩计算子单元，用于根据各混凝土纤维的轴力与混凝土纤维中心到中和轴y0，x(t)的距离的乘积之和、各钢筋纤维的轴力与钢筋纤维中心到中和轴y0，x(t)的距离的乘积之和计算第x个截面的弯矩Mx(t)＝Mcx(t)+Msx(t)；其中，Mcx(t)为t时刻第x个截面混凝土纤维的弯矩， yi，x(t)为t时刻第x个截面中第i个混凝土纤维中心到中和轴的距离；Msx(t)为t时刻第x个截面钢筋纤维的弯矩，Msx(t)＝(1-Ds,x(εs,x(t)))σs,x(εs,x(t))As(d-h+y0,x(t))+(1-Ds,x(εsc,x(t)))σs,x(εsc,x(t))A′s(h-d′-y0,x(t))；
曲线绘制子单元，用于根据所述弯矩和所述曲率，绘制所述弯矩-曲率曲线。
根据本发明提供的具体实施例，本发明公开了以下技术效果：
本发明通过在钢筋混凝土梁的受拉钢筋布置分布式光纤传感器，并将分布式光纤传感器采集到的光纤应变信号输入建立好的截面分析模型中，计算得到各个截面的损伤指标和损伤力学性能。本发明将分布式光纤传感技术与截面分析的损伤评估理论相结合，实现了将局部监测的应变反演成各个截面对应的损伤指标及损伤力学性能，实现了对损伤截面进行定量监测。
说明书附图
图1为本发明提供的一种钢筋混凝土结构损伤定量监测方法的流程图；
图2为本发明提供的截面单元划分示意图；
图3为本发明提供的混凝土纤维划分示意图；
图4为实际应用中的使用截面分析模型计算截面的损伤指标和弯矩-曲率曲线的流程图；
图5为本发明提供的一种钢筋混凝土结构损伤定量监测系统的结构图。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进 行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
本发明的目的是提供一种钢筋混凝土结构损伤定量监测方法及系统，以解决现有技术中的结构损伤分析方法无法对结构的损伤进行定量监测和评估的问题。
针对现有结构损伤监测技术的不足，本发明主要解决的问题是对损伤截面的性能进行定量监测，从而评估截面的损伤程度(钢筋损伤指标、混凝土损伤指标、截面损伤指标)和力学性能(荷载、挠度)。因此，提出了在钢筋混凝土梁的受拉钢筋布置分布式光纤传感器，并将分布式光纤传感器采集到的应变数据输入截面分析程序，计算得到各个截面的损伤指标和损伤力学性能，提供了一种对钢筋混凝土结构损伤定量监测的方法。
本发明基于分布式光纤采集的纵向受拉钢筋应变信号和Matlab编写的截面分析程序，能够定量地监测所关心截面的损伤状态。可以将监测的局部应变信号反算出各个损伤截面对应的损伤因子和力学性能，对结构整体性能的退化进行定量分析，评估构件整体性能的衰减和残余性能。为新建的钢筋混凝土结构的损伤定量监测及评估提供解决方案。
为使本发明的上述目的、特征和优点能够更加明显易懂，下面结合附图和具体实施方式对本发明作进一步详细的说明。
图1为本发明提供的一种钢筋混凝土结构损伤定量监测方法的流程图，如图1所示，方法包括：
步骤101：获取钢筋混凝土梁的纵向受拉钢筋的光纤应变信号和截面设计参数。所述截面设计参数包括几何参数和材料性能参数；所述几何参数包括截面宽度、截面高度、截面等效高度、保护层厚度和钢筋面积；所述材料性能参数包括混凝土受压峰值应力、混凝土初始切线模量和钢筋初始切线模量。
在实际应用中，预先在新建钢筋混凝土梁的纵向受拉钢筋中布置分布式光纤，并实时采集光纤应变信号。
步骤102：根据所述截面设计参数建立截面分析模型。所述截面分析模型包括混凝土损伤应力-应变关系模型和钢筋损伤应力-应变关系模型。
在实际应用中，建立损伤截面分析程序：根据截面设计参数(几何参数、材料性能参数)，在Matlab中编写截面分析程序，即建立截面分析模型，分析程序中的材料模型(应力-应变关系)采用的是混凝土损伤应力-应变关系和钢筋损伤应力-应变关系。
截面分析程序是本发明的重要组成部分，具体如下：
截面分析程序计算采用的假定如下：
(1)截面极限状态定义为受压区最外侧混凝土纤维达到极限压应变。
(2)截面受力状态符合平截面假定。
(3)截面中纤维受拉为负，受压为正。
在一个具体实施方式中，将钢筋混凝土梁沿长度方向X轴划分成m段截面单元，如图2所示，截面单元与分布式光纤应变测点数相同。将每个截面沿高度方向y轴均分成n个纤维，如图3所示。
步骤103：将所述光纤应变信号输入所述截面分析模型，得到各个截面的损伤指标和弯矩-曲率曲线。
使用截面分析程序计算截面的损伤指标和弯矩-曲率曲线的流程如图4所示，详细步骤如下：
S1：输入截面设计参数(如几何参数(如截面宽度b、截面高度h、截面等效高度、保护层厚度、钢筋面积等)、材料性能参数(混凝土受压峰值应力、混凝土初始切线模量、钢筋初始切线模量等))和分布式光纤时刻t采集的第x个截面受拉钢筋纤维的应变分布(表示成εs，x(t)，即光纤应变信号)至所述截面分析模型。本发明中用下标x表示截面编号。
S2：假设t时刻第x个截面的中和轴位置为y0,x(t)。
S3：根据所述截面设计参数、所述光纤应变信号和所述中和轴位置，利用公式φx(t)＝εs，x(t)/(y0，x(t)-d)计算t时刻第x个截面的曲率；其中，φx(t)为t时刻第x个截面的曲率，εs，x(t)为光纤应变信号，d为截面等效高度。
S4：根据所述曲率计算t时刻第x个截面的混凝土纤维的应变分布和 t时刻第x个截面的受压钢筋纤维的应变分布。
在实际应用中，计算时刻t第x个截面各个混凝土、钢筋纤维的应变分布,则时刻t第x个截面中第i个混凝土纤维的应变可表示为：εci,x(t)＝φx(t)yi，x(t)，其中，yi，x(t)为t时刻第x个截面中第i个混凝土纤维中心到中和轴的距离；t时刻第x个截面中受压钢筋纤维的应变可表示为：εsc,x(t)＝φx(t)(h-y0，x(t)-d’)，d’为保护层厚度即受压钢筋中心到最外侧受压混凝土纤维的距离。
S5：根据所述t时刻第x个截面的混凝土纤维的应变分布，利用所述混凝土损伤应力-应变关系模型计算t时刻第x个截面的混凝土纤维的应力分布和损伤指标。
S6：根据t时刻第x个截面的钢筋纤维的应变分布，利用所述钢筋损伤应力-应变关系模型计算t时刻第x个截面的钢筋纤维的应力分布和损伤指标；所述t时刻第x个截面的钢筋纤维的应变分布包括t时刻第x个截面的受拉钢筋纤维的应变分布和t时刻第x个截面的受压钢筋纤维的应变分布。
将t时刻第x个截面中各个混凝土、钢筋纤维的应变代入混凝土损伤应力-应变关系模型、钢筋损伤应力-应变关系模型计算对应时刻、截面上各个混凝土、钢筋纤维的应力分布、损伤指标。
时刻t第x个截面中第i个混凝土纤维的应力可表示为σci,x(εci,x(t))，t时刻第x个截面受拉和受压钢筋纤维应力分别可表示为：σs,x(εs,x(t))，σs,x(εsc,x(t))；t时刻第x个截面中第i个混凝土纤维的损伤指标可表示为Dci,x(εci,x(t))；t时刻第x个截面受拉和受压钢筋纤维的损伤指标分别可表示为：Ds,x(εs,x(t))，Ds,x(εsc,x(t))。
截面分析程序中的混凝土损伤应力-应变关系采用《混凝土结构设计规范》(GB 50010-2010)给出的混凝土单轴损伤应力-应变关系，计算时刻t第x个截面中第i个混凝土纤维的应力。
其中，σci,x(εci,x(t))＝(1-Dci,x(εci,x(t)))E0εci,x(t)，E0混凝土初始切线模量。
当εci,x(t)>0时，混凝土纤维受压：
其中，fc为无约束混凝土的峰值应力，ε0为与无约束混凝土的峰值应力对应的峰值应变，αc为单轴受压应力-应变曲线下降段的参数值。
当εci,x(t)<0时，混凝土纤维受拉：
其中，αt为单轴受拉应力-应变曲线下降段的参数值，为混凝土单轴抗拉强度，εt为与相对应的混凝土峰值抗拉应变。
t时刻第x个截面受拉钢筋纤维的应力σs,x(εs,x(t))＝(1-Ds,x(εs,x(t)))Esεs,x(t)；损伤指标
时刻t第x个截面受压钢筋纤维的应力σs,x(εsc,x(t))＝(1-Ds,x(εsc,x(t)))Esεsc,x(t)；损伤指标
其中，Es为钢筋初始切线模量，εy为钢筋屈服应变。
S7：根据所述t时刻第x个截面的混凝土纤维的应力分布和损伤指标以及所述t时刻第x个截面的钢筋纤维的应力分布和损伤指标计算轴力的合力。
进一步地，利用公式 计算轴力的合力；其中，∑Nx(t)为轴力的合力，Ac,i＝(bh/n(x))为第i个混凝土纤维的面积，b为截面宽度，h为截面高 度；As为受拉钢筋纤维面积；As’为受压钢筋纤维面积；n(x)是第x个截面中混凝土纤维的数量。
S8：判断所述轴力的合力是否为零。
S9：若所述轴力的合力为零，则计算t时刻第x个截面的损伤指标和弯矩-曲率曲线并输出。
S10：若所述轴力的合力不为零，则返回“设t时刻第x个截面曲率中和轴位置为y0,x(t)”的步骤。
判断t时刻第x个截面中轴力的合力∑Nx(t)是否为0；如果t时刻第x个截面中轴力的合力∑Nx(t)为0，则表示步骤S2假设的中和轴为真实中和轴，可进行下一步；如果t时刻第x个截面中轴力的合力∑Nx(t)不等于0，则需要重新假定中性轴高度，重复S2-S7的计算。
具体地，利用公式计算t时刻第x个截面的损伤指标；其中， A'＝E0Ac,iyi,x(t)2+EsAs(d-h+y0,x(t))2+EsA's(h-d'-y0,x(t))2、B'＝E0Ac,iyi,x(t)+EsAs(d-h+y0,x(t))+EsA's(h-d'-y0,x(t))、
Dci,x(εci,x(t))为t时刻第x个截面第i根混凝土纤维的损伤指标、Ds,x(εsc,x(t))为t时刻第x个截面的受压钢筋纤维的损伤指标；Ds,x(εs,x(t))为t时刻第x个截面的受拉钢筋纤维的损伤指标，E0为混凝土初始切线模量；d’为保护层厚度；Es为钢筋初始切线模量；Ac,i为第i根混凝土纤维的面积；n(x)是第x个截面中混凝土纤维的数量。另外，A、B、C、A’、B’、C’为简化计算的中间变量无具体含义。
根据各混凝土纤维的轴力与混凝土纤维中心到中和轴y0，x(t)的距离的乘积之和、各钢筋纤维的轴力与钢筋纤维中心到中和轴y0，x(t)的距离的乘积之和计算第x个截面的弯矩Mx(t)＝Mcx(t)+Msx(t)；其中，Mcx(t)为t时刻第x个截面混凝土纤维的弯矩， Msx(t)为t时刻第x个截面钢筋纤维的弯矩，Msx(t)＝(1-Ds,x(εs,x(t)))σs,x(εs,x(t))As(d-h+y0,x(t))+(1-Ds,x(εsc,x(t)))σs,x(εsc,x(t))A′s(h-d′-y0,x(t))；
根据所述弯矩和所述曲率，绘制所述弯矩-曲率曲线。
重复S1-S10可计算所有截面(m个截面)的弯矩-曲率曲线和损伤指标。
本发明将分布式光纤传感技术和损伤截面分析方法相结合，能够将采集的应变信号反演出所关心截面的损伤因子和力学性能。既能展现截面内混凝土纤维、钢筋纤维的应力、应变、损伤变量，又能量化评估截面的力学性能和损伤指标。
该发明传感器布置简单，仅需在纵向受拉钢筋布置分布式光纤传感器就能定量获取各个截面的受力状态和损伤指标。
采用本发明提供的基于分布式光纤应变的结构损伤定量监测方法(钢筋混凝土结构损伤定量监测方法)，可以对服役期间钢筋混凝土结构关键构件的损伤指标和力学性能进行实时监测，进而评估结构的安全性能，为结构的维护和抢修提供保障和指导。
本发明的钢筋混凝土结构损伤定量监测方法，该方法中分布式光纤传感器可布置于梁、柱纵向受力部件中如钢筋、FRP筋、钢-FRP连续纤维筋、钢板等。该方法的前提是获取材料的损伤应力-应变关系，可根据结构的材料类型进行替换。该方法不受结构的截面形状的限制，即可是方形截面也可是圆形截面。
本发明还提供了一种钢筋混凝土结构损伤定量监测系统，如图5所示，包括：
数据获取模块501，用于获取钢筋混凝土梁的纵向受拉钢筋的光纤应变信号和截面设计参数；所述截面设计参数包括几何参数和材料性能参数； 所述几何参数包括截面宽度、截面高度、截面等效高度、保护层厚度和钢筋面积；所述材料性能参数包括混凝土受压峰值应力、混凝土初始切线模量和钢筋初始切线模量。
模型建立模块502，用于根据所述截面设计参数建立截面分析模型；所述截面分析模型包括混凝土损伤应力-应变关系模型和钢筋损伤应力-应变关系模型。
计算模块503，用于将所述光纤应变信号输入所述截面分析模型，得到各个截面的损伤指标和弯矩-曲率曲线。
进一步地，所述计算模块503，包括：
中和轴假设单元，用于设t时刻第x个截面的中和轴位置为y0,x(t)。
曲率计算单元，用于根据所述截面设计参数、所述光纤应变信号和所述中和轴位置，利用公式φx(t)＝εs，x(t)/(y0，x(t)-d)计算t时刻第x个截面的曲率。其中，φx(t)为t时刻第x个截面的曲率，εs，x(t)为光纤应变信号，d为截面等效高度。
应变计算单元，用于根据所述曲率计算t时刻第x个截面的混凝土纤维的应变分布和t时刻第x个截面的受压钢筋纤维的应变分布。
混凝土应力计算单元，用于根据所述t时刻第x个截面的混凝土纤维的应变分布，利用所述混凝土损伤应力-应变关系模型计算t时刻第x个截面的混凝土纤维的应力分布和损伤指标。
钢筋应力计算单元，用于根据t时刻第x个截面的钢筋纤维的应变分布，利用所述钢筋损伤应力-应变关系模型计算t时刻第x个截面的钢筋纤维的应力分布和损伤指标。所述t时刻第x个截面的钢筋纤维的应变分布包括t时刻第x个截面的受拉钢筋纤维的应变分布和t时刻第x个截面的受压钢筋纤维的应变分布。
合力计算单元，用于根据所述t时刻第x个截面的混凝土纤维的应力分布和损伤指标以及所述t时刻第x个截面的钢筋纤维的应力分布和损伤指标计算轴力的合力。
判断单元，用于判断所述轴力的合力是否为零。
第一执行单元，用于若所述轴力的合力为零，则计算t时刻第x个截面的损伤指标和弯矩-曲率曲线并输出。
第二执行单元，用于若所述轴力的合力不为零，则返回“设t时刻第x个截面曲率中和轴位置为y0,x(t)”的步骤。
进一步地，所述合力计算单元，包括：
合力计算子单元，用于利用公式 计算轴力的合力；其中，∑Nx(t)为轴力的合力，Ac,i＝(bh/n(x))为第i个混凝土纤维的面积，b为截面宽度，h为截面高度；As为受拉钢筋纤维面积；As’为受压钢筋纤维面积；σs,x(εsc,x(t))为t时刻第x个截面的受压钢筋纤维的应力分布；σs,x(εs,x(t))为t时刻第x个截面的受拉钢筋纤维的应变分布；σci,x(εci,x(t))为t时刻第x个截面中第i个混凝土纤维的应力；n(x)是第x个截面中混凝土纤维的数量。
进一步地，所述第一执行单元，包括：
损伤指标计算子单元，用于利用公式计算t时刻第x个截面的损伤指标。其中， A'＝E0Ac,iyi,x(t)2+EsAs(d-h+y0,x(t))2+EsA's(h-d'-y0,x(t))2、B'＝E0Ac,iyi,x(t)+EsAs(d-h+y0,x(t))+EsA's(h-d'-y0,x(t))、
Dci,x(εci,x(t))为t时刻第x个截面第i根混凝土纤维的损伤指标、Ds,x(εsc,x(t))为t时刻第x个截面的受压钢筋纤维的损伤指标；Ds,x(εs,x(t))为t时刻第x个截面的受拉钢筋纤维的损伤指标， E0为混凝土初始切线模量；d’为保护层厚度；Es为钢筋初始切线模量；Ac,i为第i根混凝土纤维的面积；n(x)是第x个截面中混凝土纤维的数量。
弯矩计算子单元，用于根据各混凝土纤维的轴力与混凝土纤维中心到中和轴y0，x(t)的距离的乘积之和、各钢筋纤维的轴力与钢筋纤维中心到中和轴y0，x(t)的距离的乘积之和计算第x个截面的弯矩Mx(t)＝Mcx(t)+Msx(t)；其中，Mcx(t)为t时刻第x个截面混凝土纤维的弯矩， Msx(t)为t时刻第x个截面钢筋纤维的弯矩，Msx(t)＝(1-Ds,x(εs,x(t)))σs,x(εs,x(t))As(d-h+y0,x(t))+(1-Ds,x(εsc,x(t)))σs,x(εsc,x(t))A′s(h-d′-y0,x(t))。
曲线绘制子单元，用于根据所述弯矩和所述曲率，绘制所述弯矩-曲率曲线。
本说明书中各个实施例采用递进的方式描述，每个实施例重点说明的都是与其他实施例的不同之处，各个实施例之间相同相似部分互相参见即可。对于实施例公开的系统而言，由于其与实施例公开的方法相对应，所以描述的比较简单，相关之处参见方法部分说明即可。
本文中应用了具体个例对本发明的原理及实施方式进行了阐述，以上实施例的说明只是用于帮助理解本发明的方法及其核心思想；同时，对于本领域的一般技术人员，依据本发明的思想，在具体实施方式及应用范围上均会有改变之处。综上所述，本说明书内容不应理解为对本发明的限制。

Claims (8)

  1. 一种钢筋混凝土结构损伤定量监测方法，其特征在于，包括：
    获取钢筋混凝土梁的纵向受拉钢筋的光纤应变信号和截面设计参数；所述截面设计参数包括几何参数和材料性能参数；所述几何参数包括截面宽度、截面高度、截面等效高度、保护层厚度和钢筋面积；所述材料性能参数包括混凝土受压峰值应力、混凝土初始切线模量和钢筋初始切线模量；
    根据所述截面设计参数建立截面分析模型；所述截面分析模型包括混凝土损伤应力-应变关系模型和钢筋损伤应力-应变关系模型；
    将所述光纤应变信号输入所述截面分析模型，得到各个截面的损伤指标和弯矩-曲率曲线。
  2. 根据权利要求1所述的钢筋混凝土结构损伤定量监测方法，其特征在于，将所述光纤应变信号输入所述截面分析模型，得到各个截面的损伤指标和弯矩-曲率曲线，具体包括：
    设t时刻第x个截面的中和轴位置为y0,x(t)；
    根据所述截面设计参数、所述光纤应变信号和所述中和轴位置，利用公式φx(t)＝εs,x(t)/(y0,x(t)-d)计算t时刻第x个截面的曲率；其中，φx(t)为t时刻第x个截面的曲率；εs,x(t)为光纤应变信号；d为截面等效高度；
    根据所述曲率计算t时刻第x个截面的混凝土纤维的应变分布和t时刻第x个截面的受压钢筋纤维的应变分布；
    根据所述t时刻第x个截面的混凝土纤维的应变分布，利用所述混凝土损伤应力-应变关系模型计算t时刻第x个截面的混凝土纤维的应力分布和损伤指标；
    根据t时刻第x个截面的钢筋纤维的应变分布，利用所述钢筋损伤应力-应变关系模型计算t时刻第x个截面的钢筋纤维的应力分布和损伤指标；所述t时刻第x个截面的钢筋纤维的应变分布包括t时刻第x个截面的受拉钢筋纤维的应变分布和t时刻第x个截面的受压钢筋纤维的应变分布；
    根据所述t时刻第x个截面的混凝土纤维的应力分布和损伤指标以及所述t时刻第x个截面的钢筋纤维的应力分布和损伤指标计算轴力的合力；
    判断所述轴力的合力是否为零；
    若所述轴力的合力为零，则计算t时刻第x个截面的损伤指标和弯矩-曲率曲线并输出；
    若所述轴力的合力不为零，则返回“设t时刻第x个截面曲率中和轴位置为y0,x(t)”的步骤。
  3. 根据权利要求2所述的钢筋混凝土结构损伤定量监测方法，其特征在于，所述根据所述t时刻第x个截面的混凝土纤维的应力分布和损伤指标以及所述t时刻第x个截面的钢筋纤维的应力分布和损伤指标计算轴力的合力，具体包括：
    利用公式 计算轴力的合力；其中，∑Nx(t)为轴力的合力；Dci,x(εci,x(t))为t时刻第x个截面第i根混凝土纤维的损伤指标、Ds,x(εsc,x(t))为t时刻第x个截面的受压钢筋纤维的损伤指标；Ds,x(εs,x(t))为t时刻第x个截面的受拉钢筋纤维的损伤指标；Ac,i＝(bh/n(x))为第i个混凝土纤维的面积；b为截面宽度；h为截面高度；As为受拉钢筋纤维面积；As’为受压钢筋纤维面积；σs,x(εsc,x(t))为t时刻第x个截面的受压钢筋纤维的应力分布；σs,x(εs,x(t))为t时刻第x个截面的受拉钢筋纤维的应变分布；σci,x(εci,x(t))为t时刻第x个截面中第i个混凝土纤维的应力；n(x)是第x个截面中混凝土纤维的数量。
  4. 根据权利要求2所述的钢筋混凝土结构损伤定量监测方法，其特征在于，所述计算t时刻第x个截面的损伤指标和弯矩-曲率曲线，具体包括：
    利用公式计算t时刻第x个截面的损伤指标；其中， A'＝E0Ac,iyi,x(t)2+EsAs(d-h+y0,x(t))2+EsA's(h-d'-y0,x(t))2、 B'＝E0Ac,iyi,x(t)+EsAs(d-h+y0,x(t))+EsA's(h-d'-y0,x(t))、
    Dci,x(εci,x(t))为t时刻第x个截面第i根混凝土纤维的损伤指标、Ds,x(εsc,x(t))为t时刻第x个截面的受压钢筋纤维的损伤指标；Ds,x(εs,x(t))为t时刻第x个截面的受拉钢筋纤维的损伤指标；h为截面高度；As为受拉钢筋纤维面积；As’为受压钢筋纤维面积；σs,x(εsc,x(t))为t时刻第x个截面的受压钢筋纤维的应力分布；σs,x(εs,x(t))为t时刻第x个截面的受拉钢筋纤维的应变分布；σci,x(εci,x(t))为t时刻第x个截面中第i个混凝土纤维的应力；E0为混凝土初始切线模量；d’为保护层厚度；Es为钢筋初始切线模量；Ac,i为第i根混凝土纤维的面积；n(x)是第x个截面中混凝土纤维的数量；
    根据各混凝土纤维的轴力与混凝土纤维中心到中和轴y0，x(t)的距离的乘积之和、各钢筋纤维的轴力与钢筋纤维中心到中和轴y0，x(t)的距离的乘积之和计算第x个截面的弯矩Mx(t)＝Mcx(t)+Msx(t)；其中，Mcx(t)为t时刻第x个截面混凝土纤维的弯矩， yi，x(t)为t时刻第x个截面中第i个混凝土纤维中心到中和轴的距离；Msx(t)为t时刻第x个截面钢筋纤维的弯矩，Msx(t)＝(1-Ds,x(εs,x(t)))σs,x(εs,x(t))As(d-h+y0,x(t))+(1-Ds,x(εsc,x(t)))σs,x(εsc,x(t))A′s(h-d′-y0,x(t))；
    根据所述弯矩和所述曲率，得到所述弯矩-曲率曲线。
  5. 一种钢筋混凝土结构损伤定量监测系统，其特征在于，包括：
    数据获取模块，用于获取钢筋混凝土梁的纵向受拉钢筋的光纤应变信号和截面设计参数；所述截面设计参数包括几何参数和材料性能参数；所述几何参数包括截面宽度、截面高度、截面等效高度、保护层厚度和钢筋面积；所述材料性能参数包括混凝土受压峰值应力、混凝土初始切线模量 和钢筋初始切线模量；
    模型建立模块，用于根据所述截面设计参数建立截面分析模型；所述截面分析模型包括混凝土损伤应力-应变关系模型和钢筋损伤应力-应变关系模型；
    计算模块，用于将所述光纤应变信号输入所述截面分析模型，得到各个截面的损伤指标和弯矩-曲率曲线。
  6. 根据权利要求5所述的钢筋混凝土结构损伤定量监测系统，其特征在于，所述计算模块，包括：
    中和轴假设单元，用于设t时刻第x个截面的中和轴位置为y0,x(t)；
    曲率计算单元，用于根据所述截面设计参数、所述光纤应变信号和所述中和轴位置，利用公式φx(t)＝εs，x(t)/(y0，x(t)-d)计算t时刻第x个截面的曲率；其中，φx(t)为t时刻第x个截面的曲率，εs，x(t)为光纤应变信号，d为截面等效高度；
    应变计算单元，用于根据所述曲率计算t时刻第x个截面的混凝土纤维的应变分布和t时刻第x个截面的受压钢筋纤维的应变分布；
    混凝土应力计算单元，用于根据所述t时刻第x个截面的混凝土纤维的应变分布，利用所述混凝土损伤应力-应变关系模型计算t时刻第x个截面的混凝土纤维的应力分布和损伤指标；
    钢筋应力计算单元，用于根据t时刻第x个截面的钢筋纤维的应变分布，利用所述钢筋损伤应力-应变关系模型计算t时刻第x个截面的钢筋纤维的应力分布和损伤指标；所述t时刻第x个截面的钢筋纤维的应变分布包括t时刻第x个截面的受拉钢筋纤维的应变分布和t时刻第x个截面的受压钢筋纤维的应变分布；
    合力计算单元，用于根据所述t时刻第x个截面的混凝土纤维的应力分布和损伤指标以及所述t时刻第x个截面的钢筋纤维的应力分布和损伤指标计算轴力的合力；
    判断单元，用于判断所述轴力的合力是否为零；
    第一执行单元，用于若所述轴力的合力为零，则计算t时刻第x个截 面的损伤指标和弯矩-曲率曲线并输出；
    第二执行单元，用于若所述轴力的合力不为零，则返回“设t时刻第x个截面曲率中和轴位置为y0,x(t)”的步骤。
  7. 根据权利要求6所述的钢筋混凝土结构损伤定量监测系统，其特征在于，所述合力计算单元，包括：
    合力计算子单元，用于利用公式 计算轴力的合力；其中，∑Nx(t)为轴力的合力；Dci,x(εci,x(t))为t时刻第x个截面第i根混凝土纤维的损伤指标；Ds,x(εsc,x(t))为t时刻第x个截面的受压钢筋纤维的损伤指标；Ds,x(εs,x(t))为t时刻第x个截面的受拉钢筋纤维的损伤指标；Ac,i＝(bh/n(x))为第i个混凝土纤维的面积；b为截面宽度；h为截面高度；As为受拉钢筋纤维面积；As’为受压钢筋纤维面积；σs,x(εsc,x(t))为t时刻第x个截面的受压钢筋纤维的应力分布；σs,x(εs,x(t))为t时刻第x个截面的受拉钢筋纤维的应变分布；σci,x(εci,x(t))为t时刻第x个截面中第i个混凝土纤维的应力；n(x)是第x个截面中混凝土纤维的数量。
  8. 根据权利要求6所述的钢筋混凝土结构损伤定量监测系统，其特征在于，所述第一执行单元，包括：
    损伤指标计算子单元，用于利用公式计算t时刻第x个截面的损伤指标；其中， A'＝E0Ac,iyi,x(t)2+EsAs(d-h+y0,x(t))2+EsA's(h-d'-y0,x(t))2、B'＝E0Ac,iyi,x(t)+EsAs(d-h+y0,x(t))+EsA's(h-d'-y0,x(t))、
    Dci,x(εci,x(t))为t时刻第x个截面第i根混凝土纤维的损伤指标、Ds,x(εsc,x(t))为t时刻第x个截面的受压钢筋纤维的损伤指标；Ds,x(εs,x(t))为t时刻第x个截面的受拉钢筋纤维的损伤指标；h为截面高度；As为受拉钢筋纤维面积；As’为受压钢筋纤维面积；σs,x(εsc,x(t))为t时刻第x个截面的受压钢筋纤维的应力分布；σs,x(εs,x(t))为t时刻第x个截面的受拉钢筋纤维的应变分布；σci,x(εci,x(t))为t时刻第x个截面中第i个混凝土纤维的应力；E0为混凝土初始切线模量；d’为保护层厚度；Es为钢筋初始切线模量；Ac,i为第i根混凝土纤维的面积；n(x)是第x个截面中混凝土纤维的数量；
    弯矩计算子单元，用于根据各混凝土纤维的轴力与混凝土纤维中心到中和轴y0，x(t)的距离的乘积之和、各钢筋纤维的轴力与钢筋纤维中心到中和轴y0，x(t)的距离的乘积之和计算第x个截面的弯矩Mx(t)＝Mcx(t)+Msx(t)；其中，Mcx(t)为t时刻第x个截面混凝土纤维的弯矩， yi，x(t)为t时刻第x个截面中第i个混凝土纤维中心到中和轴的距离；Msx(t)为t时刻第x个截面钢筋纤维的弯矩，Msx(t)＝(1-Ds,x(εs,x(t)))σs,x(εs,x(t))As(d-h+y0,x(t))+(1-Ds,x(εsc,x(t)))σs,x(εsc,x(t))A's(h-d'-y0,x(t))；
    曲线绘制子单元，用于根据所述弯矩和所述曲率，绘制所述弯矩-曲率曲线。
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