Anti-buckling system integrating stress-driven self-centering and cathodic protection functions and design method thereof

An anti-buckling system integrating stress-driven self-centering and cathodic protection functions, comprising:

• a composite tendon, a power source, and a sensing assembly, wherein the composite tendon and the sensing assembly are installed on a steel structure column;
• the composite tendon comprises a plurality of diagonal tension assemblies, and the plurality of diagonal tension assemblies are symmetrically distributed on two sides of the steel structure column;
• each of the diagonal tension assemblies comprises a shape memory alloy (SMA) structure and a fiber-reinforced composite structure that are insulated from each other;
• the fiber-reinforced composite structure is disposed in a groove of the SMA structure;
• two ends of the SMA structure corresponding to each of the diagonal tension assemblies are connected to a positive electrode and a negative electrode of the power source respectively, and the fiber-reinforced composite structure corresponding to each of the diagonal tension assemblies is connected to the positive electrode of the power source;
• the steel structure column is connected to the negative electrode of the power source;
• and
• when the sensing assembly detects that a strain of the steel structure column reaches a preset condition, the power source applies an excitation current to the SMA structure corresponding to the diagonal tension assembly under tension, such that the diagonal tension assembly under tension recovers to a target length;
• a first lateral support and a second lateral support are provided on the two sides of the steel structure column respectively;
• the plurality of diagonal tension assemblies comprise a first diagonal tension member, a second diagonal tension member, a third diagonal tension member, and a fourth diagonal tension member;
• two ends of the first diagonal tension member are connected to a top end of the steel structure column and an upper side end of the first lateral support respectively;
• two ends of the second diagonal tension member are connected to the top end of the steel structure column and an upper side end of the second lateral support respectively;
• two ends of the third diagonal tension member are connected to a bottom end of the steel structure column and a lower side end of the first lateral support respectively;
• two ends of the fourth diagonal tension member are connected to the bottom end of the steel structure column and a lower side end of the second lateral support respectively;
• the sensing assembly comprises a first strain sensor and a second strain sensor, the first strain sensor is disposed on the first diagonal tension member, and the second strain sensor is disposed on the second diagonal tension member;
• when the first strain sensor detects that a strain of the first diagonal tension member is greater than a preset value, the power source applies an excitation current to the first diagonal tension member and the third diagonal tension member, whereby the first diagonal tension member and the third diagonal tension member recover to an initial length;
• and
• when the first strain sensor detects that a strain of the second diagonal tension member is greater than the preset value, the power source applies an excitation current to the second diagonal tension member and the fourth diagonal tension member, whereby the second diagonal tension member and the fourth diagonal tension member recover to the initial length;
• the steel structure column is a rectangular column;
• the first diagonal tension member and the third diagonal tension member are installed on one long side of the rectangular column with relatively small moment of inertia;
• the second diagonal tension member and the fourth diagonal tension member are installed on another long side of the rectangular column with relatively small moment of inertia;
• when the strain from the second strain sensor on the second diagonal tension member is less than 0 and the strain from the first strain sensor on the first diagonal tension member is greater than a preset value, the rectangular column buckles towards the second lateral support;
• the second diagonal tension member and the fourth diagonal tension member are under compression, while the first diagonal tension member and the third diagonal tension member are under tension;
• and in this case, an activation current is applied to the first diagonal tension member and the third diagonal tension member under tension to restore the first diagonal tension member and the third diagonal tension member to an original length;
• when the strain of the first diagonal tension member is less than 0 and the strain from the strain sensor of the second diagonal tension member is greater than the preset value, the rectangular column buckles towards the first lateral support;
• the first diagonal tension member and the third diagonal tension member are under compression, while the second diagonal tension member and the fourth diagonal tension member are under tension;
• and then, an activation current is applied to the second diagonal tension member and the fourth diagonal tension member under tension to restore the second diagonal tension member and the fourth diagonal tension member to the original length, wherein the preset value is MyNdl/(12EIEsAbsinq), My is a buckling moment of the rectangular column, Nd is a design axial pressure of the rectangular column, l is a height of the rectangular column, EI is stiffness of the rectangular column, Es is an elastic modulus of an SMA-carbon fiber reinforced polymer (CFRP) tendon, Ab is an area of a reinforced segment of the SMA-CFRP tendon, and q is an angle between the diagonal tension members and the rectangular column;
• and
• the groove is a spiral groove, a cross-section of the spiral groove is circular or rectangular, the spiral groove is used for anchoring the fiber-reinforced composite structure, and the fiber-reinforced composite structure has an ultimate strain range of 1.5%-2%.