CN-122019913-A - SMAF-ECC fiber stress calculation method based on multi-slit cracking effect

CN122019913ACN 122019913 ACN122019913 ACN 122019913ACN-122019913-A

Abstract

The invention relates to the technical field of material performance and provides an SMAF-ECC fiber stress calculation method based on a multi-slit cracking effect, which comprises the steps of obtaining material parameters of a material to be measured, wherein the material parameters are parameters describing mechanical behaviors of the material to be measured; the method comprises the steps of carrying out strain calculation on shape memory alloy fibers in a material to be tested according to material parameters and preset multi-crack widths to obtain shape memory alloy fiber strain, wherein the preset multi-crack widths represent the sum of opening widths of all cracks in the material to be tested which is intersected with the shape memory alloy fibers, and calculating the shape memory alloy fiber stress according to the material parameters and the shape memory alloy fiber strain based on constitutive relation of the shape memory alloy fibers. According to the invention, by establishing the fiber strain calculation model considering the accumulation widths of a plurality of cracks, the high-precision prediction from crack information to fiber stress is realized.

Inventors

YANG ZHAO
QI XIAOLONG
WU QING
MA YIFAN
Wu Juansheng
WANG XINLEI

Assignees

武汉科技大学

Dates

Publication Date: 20260512
Application Date: 20251223

Claims (10)

1. The SMAF-ECC fiber stress calculation method based on the multi-slit cracking effect is characterized by comprising the following steps of: acquiring material parameters of a material to be measured, wherein the material parameters are parameters describing mechanical behaviors of the material to be measured; according to the material parameters and the preset multi-crack width, performing strain calculation on the shape memory alloy fiber in the material to be measured to obtain the shape memory alloy fiber strain; the preset multi-crack width represents the sum of the opening widths of all cracks in the material to be tested which is intersected with the shape memory alloy fiber; based on constitutive relation of the shape memory alloy fiber, calculating shape memory alloy fiber stress according to the material parameter and the shape memory alloy fiber strain.
2. The method for calculating the stress of the SMAF-ECC fiber based on the multi-slit cracking effect according to claim 1, wherein the calculating the strain of the shape memory alloy fiber in the material to be measured according to the material parameter and the preset multi-slit width to obtain the shape memory alloy fiber strain comprises: According to the material parameters and the preset multi-crack width, performing strain calculation on the shape memory alloy fiber in the material to be measured through a first formula to obtain the shape memory alloy fiber strain, wherein the first formula is as follows: ; Wherein, the Is a strain of the fiber of the shape memory alloy, For the fracture strain of the matrix, Is the stretched length of the shape memory alloy fiber, Is a preset multi-crack width.
3. The SMAF-ECC fiber stress computing method based on multi-slit cracking effect of claim 1, wherein the constitutive relation of the shape memory alloy fiber, based on the material parameter and the shape memory alloy fiber strain, computes shape memory alloy fiber stress comprising: Calculating the shape memory alloy fiber stress according to the material parameters and the shape memory alloy fiber strain by a second formula, wherein the second formula is as follows: ; Wherein, the Is the stress of the fiber of the shape memory alloy, Is a strain of the fiber of the shape memory alloy, For the modulus of elasticity of the austenite, Is the deformation modulus of the martensite in the positive phase transition yield stage, Is the modulus of elasticity of the martensite, For the corresponding strain value at the beginning of stress induced martensitic transformation, For the corresponding strain value at the end of stress induced martensitic transformation, To control the parameters of the sharpness of the martensitic hardened corner, To control parameters of the corner sharpness of the hysteresis curve.
4. A SMAF-ECC fiber stress computing method based on a multi-slit cracking effect as recited in claim 3, wherein the parameter controlling martensitic hardening corner sharpness and the parameter controlling hysteresis curve corner sharpness are determined by: carrying out uniaxial tensile test on the single shape memory alloy fiber to obtain stress-strain data; and determining the parameter for controlling the sharpness of the martensitic hardening corner and the parameter for controlling the sharpness of the hysteresis curve by a nonlinear least square method according to the stress-strain data.
5. The SMAF-ECC fiber stress computing method based on multi-slit cracking effect as recited in claim 1, wherein the preset multi-slit width is obtained by: obtaining the matrix strain of the material to be tested; according to the matrix strain and the material parameters, calculating a preset multi-crack width according to a third formula, wherein the third formula is as follows: ; Wherein, the Is a preset width of the multi-crack, For the purpose of the strain of the substrate, Is the stretched length of the shape memory alloy fiber, Is the cracking strain of the matrix.
6. The method for calculating the stress of the SMAF-ECC fiber based on the multi-slit cracking effect according to claim 5, wherein the matrix strain and the matrix cracking strain are both measured by an SMAF-ECC test piece uniaxial tensile test.
7. An SMAF-ECC fiber stress calculation device based on a multi-slit cracking effect, comprising: the parameter acquisition module is used for acquiring material parameters of a material to be measured, wherein the material parameters are parameters describing the mechanical behavior of the material to be measured; The strain calculation module is used for calculating the strain of the shape memory alloy fiber in the material to be measured according to the material parameters and the preset multi-crack width to obtain the strain of the shape memory alloy fiber; the preset multi-crack width represents the sum of the opening widths of all cracks in the material to be tested which is intersected with the shape memory alloy fiber; And the stress calculation module is used for calculating the stress of the shape memory alloy fiber according to the material parameter and the strain of the shape memory alloy fiber based on the constitutive relation of the shape memory alloy fiber.
8. The SMAF-ECC fiber stress computing device based on multi-slit cracking effect of claim 7, wherein the strain computing module comprises: the strain calculation unit is used for calculating the strain of the shape memory alloy fiber in the material to be measured according to the material parameters and the preset multi-crack width by a first formula to obtain the strain of the shape memory alloy fiber, wherein the first formula is as follows: ; Wherein, the Is a strain of the fiber of the shape memory alloy, For the fracture strain of the matrix, Is the stretched length of the shape memory alloy fiber, Is a preset multi-crack width.
9. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the SMAF-ECC fiber stress calculation method based on the multi-slit effect as claimed in any one of claims 1 to 6 when the computer program is executed.
10. A non-transitory computer readable storage medium storing computer instructions for causing a computer to perform the SMAF-ECC fiber stress computing method based on the multi-slit effect of any one of claims 1 to 6.

Description

SMAF-ECC fiber stress calculation method based on multi-slit cracking effect Technical Field The invention relates to the technical field of material performance, in particular to an SMAF-ECC fiber stress calculation method based on a multi-slit cracking effect. Background By doping Shape Memory Alloy Fibers (SMAF) into engineering cement-based composite materials (ECC), the novel composite materials, namely the shape memory alloy fiber reinforced engineering cement-based composite materials (SMAF-ECC), are prepared, the multi-slit cracking effect of the ECC materials is achieved, and micro cracks of an ECC matrix can be closed and residual strain of the ECC matrix can be reduced by utilizing super elasticity of the SMAF materials. As a typical fiber-reinforced cement-based composite material, SMAF-ECC is widely used in the civil engineering field due to its excellent self-healing property and high ductility. In the design and durability evaluation of concrete structures, control of crack width is critical. The width of the crack not only affects the bearing capacity of the structure, but also directly relates to the corrosion of the steel bar and the service life of the structure. Therefore, research on the relation of the fiber stress and crack width of the SMAF-ECC material has important reference value for concrete structural design. In the tensile process, the SMAF-ECC often presents a multi-slit cracking mode, densely distributed micro-slits are formed, the micro-slit spacing is smaller (usually 1-5 mm), and a plurality of micro-slits exist in the length range of a single SMAF, so that the relation between the fiber stress and the width of the matrix slit is obviously different from the mechanical model under the traditional single-slit assumption. At present, most of mechanical models aiming at the relation between fiber stress and crack width are based on single crack assumption, namely, only one crack exists in the length range of a single fiber, and the relation between the SMAF stress and the multi-crack width of an ECC matrix cannot be accurately reflected by the mechanical models. Accordingly, there is a need for a fiber stress-crack width calculation method that accurately describes the multi-slit cracking effect to improve the reliability of crack control and the accuracy of durability assessment. Disclosure of Invention The invention aims to provide an SMAF-ECC fiber stress calculation method based on a multi-slit cracking effect so as to solve the technical problems. The technical scheme includes that the SMAF-ECC fiber stress calculation method based on the multi-slit cracking effect comprises the steps of obtaining material parameters of a material to be measured, wherein the material parameters are parameters describing mechanical behaviors of the material to be measured, calculating strain of a shape memory alloy fiber in the material to be measured according to the material parameters and preset multi-slit widths, and obtaining the strain of the shape memory alloy fiber, wherein the preset multi-slit widths represent the sum of the opening widths of all slits in the material to be measured, intersecting the shape memory alloy fiber, and calculating the stress of the shape memory alloy fiber according to the material parameters and the strain of the shape memory alloy fiber based on constitutive relation of the shape memory alloy fiber. The method has the beneficial effects that the high-precision prediction from crack information to fiber stress is realized by establishing the fiber strain calculation model considering the accumulated widths of a plurality of cracks. Compared with the traditional single-crack model, the method fully reflects the actual mechanical behavior of the SMAF-ECC material under the multi-crack cracking condition, and the accuracy and reliability of fiber stress calculation are remarkably improved. On the basis of the technical scheme, the invention can be improved as follows. Further, according to the material parameter and the preset multi-crack width, performing strain calculation on the shape memory alloy fiber in the material to be measured to obtain a shape memory alloy fiber strain, including: According to the material parameters and the preset multi-crack width, performing strain calculation on the shape memory alloy fiber in the material to be measured through a first formula to obtain the shape memory alloy fiber strain, wherein the first formula is as follows: ; Wherein, the Is a strain of the fiber of the shape memory alloy,For the fracture strain of the matrix,Is the stretched length of the shape memory alloy fiber,Is a preset multi-crack width. Further, the constitutive relation based on the shape memory alloy fiber calculates shape memory alloy fiber stress according to the material parameter and the shape memory alloy fiber strain, comprising: Calculating the shape memory alloy fiber stress according to the material parameters and the shape memo