8 results about "Secant modulus" patented technology

The invention provides a calculation method for the elastic modulus of a soil-rock mixture based on a mesoscopic structure model, relevant to the field of meso-numerical simulation of geotechnical materials. It includes the following steps: obtaining the gradation curve of soil-rock mixture particles through a screening test and constructing a two-dimensional random meso-structure model of the mixture with varying stone contents. Using the finite element method, a biaxial compression numerical test is conducted on the model under different stone contents and confining pressures. The equivalent elastic modulus of the mixture is determined by the corresponding secant elastic modulus at an axial strain of 1%. This macro-equivalent elastic modulus, considering stone content and confining pressure, is then fitted. This method effectively addresses the challenge of presenting accurate physical and mechanical parameters in engineering design and construction, making it directly applicable to practical engineering involving soil-rock mixture materials.

The invention provides a ceramic-based composite material interface parameter optimization identification method, medium and equipment considering multiple characteristics of a hysteresis loop under fatigue load, and belongs to the field of ceramic-based composite material interface parameter identification. Comprising the following steps: carrying out a CMC fatigue test, and extracting multiple features of a hysteresis loop under different cycle numbers; deducing a theoretical expression of multiple features of the hysteresis loop in different interface debonding and slippage states; establishing an inverse function relationship between the interface shear stress and the hysteresis loop secant modulus as an interface shear stress identification function; establishing an optimization model based on an interface shear stress identification result; and solving the optimization model by adopting a genetic algorithm, and identifying the degradation rule of the interface shear stress along with the cycle index according to the optimized key influence parameters. According to the method, an interface parameter identification mechanism guided by a main feature is adopted, an optimization model compatible with multiple features of the hysteresis loop is constructed, high-precision prediction of the features of the hysteresis loop and the fatigue life is realized based on an iterative verification system, and the reasonability of an interface shear stress identification result is proved.

The present invention relates to a tire (10) comprising a crown (12), a first and a second side (30A, 30B), a first and a second bead (32A, 32B), an inner surface (34) delimiting an annular cavity (36), a first outer layer (33A) arranged radially and / or axially outside and in contact with a first inner layer (37A), and a reinforcing structure (52) extending continuously in the annular cavity (36) from the first side (30A) and / or the first bead (32A) to the crown (12), through the first inner layer (37A) and at least partially penetrating the first outer layer (33A). The modulus ratio between the nominal secant modulus at 10% elongation of the first outer layer (33A) and the nominal secant modulus at 10% elongation of the first inner layer (37A) is strictly greater than 1.0.

The invention relates to a tunnel surrounding rock crustal stress rapid determination and verification method based on secant modulus, and belongs to the technical field of geotechnical engineering testing. The method comprises the following steps: firstly, sampling from a drill hole, sampling a directional thick rock core, and drilling cylindrical rock samples in all directions in the thick rock core; then preloading the rock sample for specified time; the method comprises the following steps: performing uniaxial compression on a sample at a higher level, synchronously acquiring axial and radial strain data by using a strain gauge in the compression process, and drawing a stress-strain curve; obtaining a strain value of a corresponding stress increment by using a secant modulus; calculating a strain difference by using a strain difference function to obtain a characteristic SMM curve; determining a normal stress through a strain difference function, establishing a simultaneous equation to solve a stress tensor, and obtaining the size and direction of a principal stress through eigenvalue analysis; the crustal stress measured by the secant modulus method is substituted into the calculated displacement, and degradation correction is carried out by considering the influence of construction disturbance; and comparing the actually measured displacement with a theoretical calculation value for verification.

The invention discloses a karst area extrusion and expansion branch pile settlement calculation method considering the extrusion and expansion compaction effect, and the method comprises the steps: calculating the self-weight stress, confining pressure and partial principal stress of a soil layer through on-site drilling coring, indoor soil test, triaxial compression test and single pile test, and obtaining a relation curve of the partial principal stress and axial strain; the method comprises the following steps: establishing a pile-soil three-dimensional model based on finite element software, respectively arranging extrusion and diffusion hard areas on the lower part and the periphery of a supporting disc, establishing analysis steps by combining a graded load sequence, calculating a soil body secant modulus between adjacent loads, endowing differentiated elastic modulus, and completing corresponding elastic modulus assignment and finite element calculation under each analysis step, extracting a pile top settlement value, comparing the pile top settlement value with a field test pile load-displacement curve, and substituting the pile top settlement value into engineering pile design parameters to estimate instantaneous and long-term settlement; the method can accurately quantify the squeezing and diffusion compaction effect, is adaptive to the complex stratum of the karst area, and has important guiding significance for further estimating the settlement of the engineering pile applied on a large scale subsequently.

The application discloses a kind of polyurethane grouting constitutive model construction method considering damage and compaction coupling effect, step 1: the material macroscopic stress response is decomposed into the damage term caused by cell wall rupture and the compaction term caused by pore compaction;Step 2: based on Weibull distribution, establish damage evolution equation, combined with initial secant modulus to establish damage term mathematical expression;Step 3: draw lessons from the thought of Avalle model to build compaction strengthening function;Step 4: the damage term and compaction term are superimposed to form coupled constitutive model;Step 5: through uniaxial compression test data, model parameters are jointly calibrated using least squares method.The model parameters of the application have clear physical meaning, and the calibration method is simple and efficient, which can quickly predict the stress-strain relationship of polyurethane grouting material at different loading stages in engineering site, and is suitable for road repair, tunnel reinforcement and other fields.

The application discloses a method for determining a filled wall constitutive model considering stiffness contribution, and relates to the field of finite element simulation, which comprises the following steps: establishing a five-section constitutive model of a diagonal bracing, determining the elastic modulus of the diagonal bracing, the tangent modulus of a strengthening section of the diagonal bracing, the corresponding secant modulus of the ultimate strain of the diagonal bracing, the ultimate strength of the diagonal bracing, the yield strength, the residual strength, the starting point strain corresponding to the ultimate strength of the diagonal bracing, and the end point strain corresponding to the ultimate strength of the diagonal bracing, correcting the ultimate strength of the diagonal bracing, the yield strength and the residual strength by using a strength reduction coefficient, and correcting the starting point strain corresponding to the ultimate strength of the diagonal bracing by using a starting point strain correction coefficient. The application can give material parameters of a simplified model corresponding to a wall body under the influence of different factors, and then accurately simulate the stiffness contribution of different wall bodies at different stages to the structure, so as to realize a structure modeling method considering the stiffness of the filled wall.

The invention provides a glacier debris flow mechanical property sample preparation and test method, which comprises the following steps: preparing test moraine soil with similar particle content and proper particle size proportion through a parallel grading method, and fully mixing ice particles with the test moraine soil to prepare an ice-soil mixture of which the volume ice content accords with test setting; a series of monotonic triaxial tests are carried out on ice-soil mixtures with different volume ice contents and different environment temperatures under different confining pressures, and the influences of the ice contents and the environment temperatures on the stress-strain relation, the shear strength, the Young modulus, the secant modulus, the Poisson's ratio, the dilatancy angle, the friction angle and the cohesive force are determined. The obtained mechanical behavior results of the ice-soil mixture at different temperatures are helpful for explaining the interaction between ice and soil particles, and have important significance on disaster prevention and control of existing Sichuan and Tibet railways and future infrastructures.