49 results about "Strain softening" patented technology

The invention discloses a numerical simulation determination method of a deep high-stress roadway drilling pressure relief parameter. Before simulation is carried out, a test roadway surrounding rock sample is firstly subjected to a loading and unloading test in a laboratory, an attenuation relationship between a rock sample strength parameter and a damage variable is obtained by fitting and is embedded into a FLAC<3D> (Fast Lagrangian Analysis of Continua) built-in strain softening constitutive model, and an actual measurement mine pressure expression law of a test roadway is taken as a known characteristic value to carry out inversion on the numerical calculation model parameter of a rock mass. A deep roadway drilling pressure relief numerical calculation model is established to simulate and analyze the influence law of a pressure relief drilling orientation, pressure relief opportunity and drilling parameters (diameter, length and inter-row spacing) on the stability of roadway surrounding rock, and a determination method of each factor which affects a pressure relief effect is put forward, and a drilling pressure relief technology system is perfected. The numerical simulation determination method considers the mutual action relationship of a pressure relief degree and the stability of the surrounding rock while pressure relief drilling parameters are determined, and the designed pressure relief drilling can perform a maximum pressure relief effect on a premise that the stability of the surrounding rock is guaranteed. The method is simple and exhibits high application value.

A medical tubing is disclosed which includes a first material extending between proximal and distal ends of the tubing and which defines a lumen of the tubing. The tubing also includes a second material extending between at least portion of the distance between the proximal and distal ends of the tubing and that is embedded in the first material. The second material is fractured. The first material is flexible and the second material is relatively rigid and brittle and the two materials combined to provide a medical tubing that exhibits strain softening behavior.

The invention discloses an underground cavity analysis method considering nonlinear softening and dilation characteristics of surrounding rock. According to the method, a hyperbolic softening model based on the characteristics of the Hoek-Brown criterion is established according to the characteristic that the strength parameter of the surrounding rock of a tunnel is weakened with the increasing of the strain of a plastic zone, the model is based on the characteristics of a resultant stress-strain curve of the surrounding rock, and reflects the nonlinear characteristics of the surrounding rock through example verification, the model is applied to analysis for the surrounding rock subjected to strain softening in underground construction, and a new method for an underground cavity analysis is established by considering the nonlinear softening and non-associated flow characteristics as well as a nonlinear failure criterion of a rock mass; the solutions of the stress of the underground cavity, the deformation of the cavity and the radius of the plastic zone are obtained; according to the method disclosed by the invention, the dilation characteristics of the surrounding rock are considered according to a non-associated flow criterion, and with regard to the deformations of the surrounding rock under different plastic models, application example results indicate that the strain dilation of a rock-soil material with dilation and strain softening is considered to be safe.

A finite element method for predicting crack opening and propagation entails defining a succession of overlapping interface elements at a potential crack plane, each element having a bound node pair and side node pairs spaced from the bound node pair to sense approach of a crack. An energy-based fracture mechanics criterion determines whether release occurs at the bound nodes and, if so, the displacement between the bound nodes is calculated based on a strain softening law. The process is repeated for each element in sequence.

The invention relates to a borehole wall sloughing analysis method which comprises the steps of parameter collection and input (1), initial stress processing (2), first time of stress release (3), first step of second time of stress release (4A), second step of second time of stress release (4B), characteristic value evaluation (5), generalized force and generalized displacement (6), path curve balancing (7), and collapse pressure processing (8). Evaluation is conducted according to a minimum obtained characteristic value (Mu1) m, and when the minimum obtained characteristic value (Mu1) m is more than 0, if m is less than M, m plus 1 arrows m, thus entering the second step of the second time of the stress release (4B); otherwise, a total field is obtained; when the minimum characteristic value (Mu1) m is less than 0, a disturbance field is calculated according to an interpolation method; and the collapse pressure qcr and a plastic area distribution area corresponding to the qcr are calculated, so as to determine the density of collapse prevention drilling fluid. The borehole wall sloughing analysis method has the effect of being capable of analyzing the borehole wall stability of a strain softening plastic stratum under the condition of non-uniform ground stress; and the density of the collapse prevention drilling fluid is designed, thus playing the role of protecting a reservoir stratum during on-site drilling.

The invention discloses a saturated clay sample strength and strain softening parameter measuring device based on full-flow penetration, and belongs to the technical field of geotechnical, geology andenvironment research. The device mainly comprises two parts, namely, an overlying pressure loading system and a full-flow penetration system. Mainly for the problem of incomplete backflow of a soil body in a process of measuring soil body strength and strain softening parameters of a saturated clay by applying a full-flow penetrometer, by applying a working principle of a traditional consolidometer, the backflow of the soil body is guaranteed through vertical pressurization of a soil sample, so that the applicability of the full-flow penetrometer in the aspect of soil body strength and strainsoftening parameter measurement is improved, and an important practical value is achieved for experimental research and marine engineering design. The device can be applied to the measurement of laboratory soil samples and undisturbed soil samples in marine exploration, so that the undrained shear strength of the soil samples, the soil body strength after sufficient disturbance and the softeningparameters of the soil body are obtained. Finally reliable soil body material parameters are provided for design and stability evaluation of facilities such as seabed pipelines, ocean foundations andthe like.

The invention relates to an earthquake slope stability analysis method considering sliding surface dynamic progressive damage, and belongs to the technical field of slope stability. The method includes: based on the slope sliding surface damage evolution rule under the earthquake effect, obtaining strength parameter characteristics and a dynamic attenuation law of the slope geotechnical material by adopting a mechanical test; constructing a characterization material strength parameter attenuation strain softening model and a fracture surface vibration degradation model; based on a dichotomy strength reduction method and a maximum shear strain increment, determining a critical state sliding surface position under a slope static force state; furthermore, by combining a sliding surface dynamic progressive failure theory and a vector sum method, an earthquake side slope safety factor time-history curve is solved in numerical calculation, the stability state of the side slope under the earthquake action is truly reflected, and the accuracy and reliability of a numerical calculation result are improved.

A Cu-based bulk and amorphous alloy composite and a preparation method thereof belong to the field of material science. The Cu-based bulk and amorphous alloy composite comprises the following ingredients by percent: 40-50% of Cu, 40-50% of Zr, 0-10% of Al and 0-7% of M, wherein M is any one of Nb, Hf and Y. After repeated smelting in a smelting furnace copper crucible, on dependency of self-weight, a self-flowing pouring method is adopted to prepare the Cu-based bulk and amorphous alloy composite. The problems of room-temperature brittleness and strain softening of amorphous alloy are effectively solved, and favorable tensile plasticity is achieved.

The invention provides a strain softening shear constitutive model and displacement change based structural plane control slope stability dynamic elevation method, including landslide survey, stress analysis, building of an anti-skating force computing model, calculating of free face removal load, determining of structural plane shear constitutive equation, building of structural plane control slope body motion equation, calculating curves of displacement process of a potential slip mass and the like. Real-time stability status of the structural plane control slope can be judged dynamically bythe method according to field deformation monitoring documents. Long-term stability of the structural plane control slope of rock can be predicted to a certain degree according to the calculated convergence of the displacement of the slip mass.

The invention discloses a construction method of a polycarbonate uniform constitutive model based on tensile tests and compression tests, and aims to solve the technical problem that the accuracy of a constitutive model established by a conventional construction method is low. According to the construction method, through the description of the linear elastic phase, yield phase, strain softening phase, and strain hardening phase of polycarbonate, a large amount of tensile tests and compression tests under different strain rates and temperatures and massive loading/unloading tests are carried out to determine the related parameters of a material model under real stress-strain, especially, through the loading/unloading tests, the influence of the inner damage of the material on the mechanical properties is written into the constitutive model, the parameters of the model are reasonably optimized, the number of the parameters is reduced, at the same time, the accuracy of the constitutive model is guaranteed, and at the same time, the tensile constitutive model and the compression constitutive model are effectively unified and combined.

The present invention discloses a side slope dynamic stability assessing method based on a Swedish slice method and a simplified strain softening theory, and belongs to the technical field of geological engineering. The method comprises: dividing a side slope vertical bar into n soil blocks; using a strain of the soil block as a parameter; according to a simplified relationship between the strain and a stress, determining a value of the stress of the soil block; and based on the Swedish slice method, calculating stability of a side slope. According to the method provided by the present invention, a dynamic progressive breakage process of the side slope is considered, and according to the change of the strain of the soil block in the breakage process, information about a change in a safety factor in the breakage process of the side slope is determined. The method is simple in principle, convenient for calculation and applicable to dynamic stability analysis of a stain softening side slope.

The invention relates to a high-strength high-plasticity Cu-Zr-Zn amorphous composite and a preparation method. The atomic feature ratio of the high-strength high-plasticity Cu-Zr-Zn amorphous composite is Cu47.25Zr47.25Zn4.5. The Cu47.25Zr47.25Zn4.5 amorphous composite prepared through a rapid solidification method not only has the excellent amorphous mechanical property, such as the high breaking strength (1713+/-75 MPa), the large elastic limit (2.0+/-0.1%) and the like, but also the brittleness caused by shear zone high localization, the low plasticity caused by strain softening and other defects are overcome. In the deformation process at the room temperature, the amorphous composite has the good plasticity (6.8+/-0.8%), and furthermore the hardening capacity of micro processing is showed.

The invention belongs to the technical field of geotechnical, geological and environmental researches, and provides a long-distance continuous measurement device for soil mass parameters of soft soilsites. The device comprises a dragging structure main body I, a soil mass parameter measurement system II and a dragging system III. The device breaks through the limitation that the traditional single-point vertical measurement devices cannot obtain the transverse continuous soil mass parameters; the transverse long-distance continuous field measurement of the parameters such as soil mass intensity, strain softening and friction effect between soil masses and structure interfaces can be completed through one dragging test; and the measured parameters can be used for instructing the design andconstruction of jetty projects and projects such as seabed oil and gas pipelines, cables and optical cables. Along with the daily increasing of deep sea oil and gas resource development, the device disclosed by the invention has important significance for measuring the seabed soil mass parameters, designing the engineering facilities such as seabed pipelines, seabed cables and the like and carrying out stability evaluation.

The invention belongs to the technical field of researches such as rock-soil, geology and environment, and provides a horizontal continuous measuring method for soil mass parameters of a soft soil site. The horizontal continuous measuring method for the soil mass parameters of the soft soil site comprises the following main measuring steps of arranging soil mass strength measuring devices at the front end of a towing device, arranging soil mass strain softening relationship measuring devices at the bottom end of the towing device, and measuring interface friction parameters between a soil massand a structure, wherein the towing device actively or passively walks in a soft soil layer, a part of the towing device in walking is ensured to penetrate into a soil layer to be measured, and the penetration depth of the towing device is controlled through adjusting balance weight above the towing device and a towing angle of the towing device. The method provided by the invention breaks through the limitation that the horizontal continuous soil mass parameters cannot be acquired through a traditional single-point vertical measuring method, and can accomplish the horizontal long-distance continuous field measurement of the parameters such as the soil mass strength, the strain softening, and the interface friction effect between the soil mass and the structure through a one-time towing test; and the measured parameters can be used for guiding design and construction of projects such as breakwater projects, oil and gas offshore pipelines, cables and optical cables.

The invention relates to a designing method of a coal pillar dam body of a coal mine underground reservoir and belongs to the technical field of comprehensive utilization of mineral engineering and hydraulic engineering. The problems that in the prior art, a designing method of the coal pillar dam body of the underground reservoir has blindness and lacks in scientificity and practicability are solved. The designing method comprises the following steps that firstly, physical and mechanical parameters of coal and rock with different water contents are tested; secondly, deformation and stress distribution models of the coal pillar dam body of the underground reservoir are established; thirdly, a coal body ideal elasto-plastic strain softening model is established; and fourthly, a coal pillardam body elasto-plastic deformation model is established, and a coal pillar dam body width calculation method is obtained. According to the designing method of the coal pillar dam body of the coal mine underground reservoir, the data calculation amount is small, and the reliability and calculation precision in design of the coal pillar dam body of the underground reservoir can be improved.

The invention belongs to the technical field of the rock-soil, geology and environment and like research, and provides a large-range soft soil site soil body parameter continuous measurement device. The device comprises a dragging structure main body I, a soil body parameter measurement system II and a dragging system III. The device disclosed by the invention breaks through the boundedness that the traditional single-point vertical measurement device cannot acquire the rock stratum layer continuous soil body parameter, the transverse long-distance continuous field measurement of the soil bodystrength, the strain softening and the soil body and structure interface friction effect and like parameters can be accomplished through once dragging test, the measured parameters can be used for guiding the design and construction of the breakwater engineering, the seabed oil and gas pipeline, cable, and optical cable. Along with the increasing of the deep sea oil and gas resource development,the seabed soil body parameter is measured based on the method, and then the device has significance for the design and stability evaluation of the seabed pipeline and seabed cable and like engineering facilities.

The invention provides a shield excavation face spread joint fluid-solid coupling safety degree analysis method which comprises the steps that a spread joint strain softening model of an excavation face is established, a rock mass of the excavation face is divided into a plurality of units, and each unit is composed of a rock block and a joint; judging an elastic stage and a yield stage of the rock mass and the joint; safety calculation is conducted on the rock blocks and joints in the elastic stage/yield stage; selecting the rock mass/joint with the minimum safety degree in the elastic stage/yield stage; permeability coefficient calculation is conducted on the rock mass/joint with the minimum safety degree; substituting the safety coefficient into fluid-solid coupling numerical calculation to carry out iterative calculation so as to monitor the dynamic change of the permeability coefficient; by calculating the safety degree of each unit of the rock mass and determining the permeability coefficient of the rock mass, the shield excavation surface local stability monitoring of rock mass fluid-solid coupling is realized, the permeability coefficient dynamic change of the rock mass spread over joint characteristics is clearly reflected, and the shield excavation surface analysis accuracy under the spread over joint condition is improved.