14 results about "Plastic yielding" patented technology

The invention relates to the technical field of tunnels and underground engineering, in particular to an analysis method and related equipment for the time-varying stability of surrounding rock of a super-large-depth tunnel, and the method comprises the steps: obtaining engineering geological survey data and engineering design data, constructing a tunnel numerical model, carrying out the crustal stress initialization to obtain an initialized model, and carrying out the initial crustal stress balance processing; clearing the balanced model displacement field to obtain a reference model; configuring an elastic-plastic-viscous constitutive model for the surrounding rock of the reference model, simulating a tunnel excavation construction process, and identifying a plastic yield unit in the model to obtain an excavation simulation result containing plastic unit information; based on the yield state of the plastic yield unit, carrying out real-time dynamic reduction on physical and mechanical parameters of the plastic unit, and judging the stability of the surrounding rock by combining a preset stability criterion to obtain a stability analysis result; and outputting a surrounding rock time-varying stability analysis report. According to the method, the precision of time-varying stability analysis of the surrounding rock of the super-large buried-depth tunnel is improved.

A method for establishing a high-efficiency equivalent honeycomb numerical model relates to the field of vibration reduction, and comprises the following steps: carrying out tests of a honeycomb structure, including a mechanical parameter calibration test and a verification test; establishing a high-efficiency equivalent honeycomb numerical model according to a mechanical property test result obtained from the mechanical parameter calibration test; carrying out secondary development and verification on an elastic-plastic constitutive and damage model; in order to verify the effectiveness of the developed equivalent honeycomb model, the method can accurately represent the characteristics of anisotropy, strain rate effect, shear failure and the like of the honeycomb structure, and realizes high-precision prediction of honeycomb mechanical response, crushing deformation and shear tear failure under complex working conditions. A three-dimensional anisotropic constitutive model is established for the first time, the anisotropy of honeycomb elastic and plastic yield along with out-of-plane angle change can be accurately described, and the in-plane angle change anisotropy caused by the thickness difference of all edges of the honeycomb can be effectively reflected.

The invention discloses a rock-soil structure bearing path generation method based on plastic limit analysis. The rock-soil structure bearing path generation method comprises the steps that a design domain, external load applying conditions, geometric constraint conditions and boundary constraint conditions of a rock-soil structure are established; introducing a plastic constitutive relation, selecting a yield criterion, and establishing a yield constraint condition; analyzing the rock-soil structure model based on a plastic limit analysis theory; according to a plastic limit analysis result, identifying a main bearing path of the rock-soil structure in a limit bearing state; the rock-soil structure configuration is adjusted, the structural participation degree of a main bearing path area is enhanced, and the structural participation degree of a low-efficiency bearing area is weakened; after adjustment, the plastic limit analysis and bearing path identification process is repeatedly executed until the spatial distribution of the bearing path tends to be stable; and outputting the rock-soil structure configuration which meets the plastic yield constraint condition and is stable in bearing path. According to the method, the main bearing path of the rock-soil structure can be identified in the ultimate bearing state, and a reasonable structure configuration is determined accordingly.

The invention discloses a viscoelastic-plastic numerical simulation method, which comprises the following steps of: receiving physical modeling and solving control data of a viscoelastic-plastic material, constructing a convex cone planning model for uniformly describing elastoplasticity, viscoelasticity and friction multi-physical field coupling behaviors according to the physical modeling and solving control data, expressing a plastic yield criterion and a viscous flow law as second-order cone constraints, converting the model into a second-order cone complementary equation; converting the equation into an implicit immobile point iterative equation by adopting a modular system matrix splitting iterative algorithm, performing matrix splitting on a system stiffness matrix, and constructing an iterative solution format with calculation complexity at a quadratic level; and performing iterative calculation to convergence based on the format and the input data, and outputting numerical results of a displacement field, a stress field and a strain field. According to the method, multi-field coupling behaviors are unified to a convex cone planning framework, solving is conducted through an efficient iterative algorithm, the calculation efficiency and stability of large-scale viscoelastic-plastic numerical simulation are improved, and the problem of calculation bottleneck caused by existing commercial software multi-field decoupling and general solver explicit inversion is solved.

The invention discloses a strain-driven elastic-plastic damage prediction method with a damage cross-border control factor, which relates to the field of elastic-plastic damage prediction, and comprises the following steps: establishing a plastic yield criterion, a non-associated flow rule and a hardening rule; carrying out incremental updating on the plastic internal variable by adopting a return mapping algorithm of a Newton iteration format containing a self-adaptive factor; judging the initial damage state of the material by adopting a parabolic failure criterion, and deducing equivalent strain conjugated with equivalent stress; introducing a damage border-crossing control factor, and mapping equivalent stress and equivalent strain which exceed a real threshold value when the damage is started back to a real damage starting state by referring to a plastic mechanics return mapping algorithm; and establishing a linear damage evolution criterion containing equivalent strain, and introducing the unit size and fracture toughness into the linear damage evolution criterion in combination with the crack zone model. According to the method, the problem that an existing elastic-plastic damage model still has remarkable defects in the aspects of driving mechanism self-consistency, damage starting accuracy, grid independence and the like is solved.

The invention discloses a machining method for improving the strength and ductility of a metal material, and relates to the technical field of metal material strengthening. Comprising the following steps that a metal sample is machined into a structure comprising a clamping section, a transition arc and a scale distance section, and a prefabricated part is obtained; pre-treating the prefabricated part to obtain a pre-treated sample; soaking the pretreated sample in liquid nitrogen, and then carrying out clockwise and anticlockwise alternate repeated cyclic torsion treatment in a liquid nitrogen environment to form a torsion sample with a gradient dislocation structure; and carrying out annealing treatment on the torsion sample at 10-200 DEG C to obtain a reinforced sample. High-density dislocation and small-angle grain boundaries are accumulated through alternate cyclic torsion in the clockwise direction and the anticlockwise direction at the low temperature, a gradient nanoscale low-angle dislocation structure is formed, progressive plastic yield from the surface to the core part is shown, the strength of gradient metal formed after strengthening is remarkably improved, high ductility is reserved, and the performance of the gradient metal is improved. And the overall mechanical property is improved.

The invention discloses a post-treatment method for additive manufacturing austenitic stainless steel and the additive manufacturing high-strength and high-plasticity austenitic stainless steel. The post-treatment method is combined with surface plastic deformation treatment and low-temperature heat treatment to excite the interior of the austenitic stainless steel to form a high-density nano-twin crystal structure, and comprises the following steps: carrying out surface plastic deformation treatment on an austenitic stainless steel base material subjected to additive manufacturing; and the austenitic stainless steel subjected to surface plastic deformation treatment is subjected to low-temperature annealing treatment, the annealing temperature ranges from 150 DEG C to 400 DEG C, the annealing treatment heat preservation time ranges from 1 h to 10 h, and the austenitic stainless steel of the high-density nano-twin crystal structure is prepared. The austenitic stainless steel obtained through treatment has high strength and high plasticity at the same time, the yield strength ranges from 710 MPa to 840 MPa, and the elongation at break ranges from 58% to 96%.

The application discloses a thermosetting resin elastoplastic-damage simulation method based on a hygrothermal effect. Under the hygrothermal effect, the corresponding relationship between the glass transition temperature of the thermosetting resin and the tensile and compression performance under uniaxial load is expressed through mathematical analysis means based on the judgment of the strength criterion and the plastic yield criterion, a constitutive model is established, the constitutive model is programmed, full-size modeling is carried out according to the pattern in the test, and the simulation result is verified. Compared with the prior art, the thermosetting resin elastoplastic-damage simulation method based on the hygrothermal effect has the characteristics of few parameters and high precision.

The application discloses a low-density Ni-Co-Fe-Cr-based deformed high-entropy high-temperature alloy resistant to 750 DEG C and a preparation method thereof. The alloy comprises Ni, Co, Fe, Cr, Mo, Al, Ti, Nb, C, B and Zr, and the alloy composition wt.% is as follows: Co is 12-25, Fe is 8.5-17.5, Cr is 15.5-17.0, Mo is 2.0-3.5, Al is 1.5-3, Ti is 2-4, Nb is 0-5.7, C is 0.01-0.05, B is 0.005-0.02, Zr is 0.01-0.03, and Ni is the balance. The atomic percentage ratio of (Ti+Nb) / Al is 0.8-2, and the atomic percentage ratio of Cr / Mo is 9-14.5. The alloy obtained by the application has good mechanical properties and excellent processing deformation capacity, the room-temperature yield strength is greater than 1100 MPa, the room-temperature plasticity is greater than 15%, and the 750 DEG C yield strength is greater than 950 MPa.

The utility model belongs to the technical field of detection equipment, and relates to a metal material plasticity yield strength detection device. The detection device comprises a rectangular working table, and a supporting and pressing ring assembly capable of moving in the width direction of the rectangular working table is arranged on the table top of the rectangular working table; an inverted-U-shaped auxiliary frame is further fixed to the table top of the rectangular workbench, the auxiliary frame is parallel to the length direction of the rectangular workbench and located in the middle of the rectangular workbench, and a pressure detection assembly capable of conducting lifting movement is arranged on a cross beam of the auxiliary frame; a telescopic clamping assembly is fixedly arranged on the lower portion of a supporting rod of the auxiliary frame, and the telescopic clamping assembly makes contact with the side edge of the metal material to be detected so that the metal material to be detected can be clamped and fixed. According to the utility model, the metal material is supported by the lower backing ring, the area around the point to be measured is pressed by the upper pressing ring, and the influence of the stress state around the deformation point on the yield strength of the adjacent area can be avoided through the pressing effect of the upper pressing ring.

The present application relates to the technical field of coal mining safety, and discloses a small coal pillar prevention and control method for rock burst of ground fracturing weakened roof, which comprises the following steps: calibrating geological parameters; then, arranging a roadway in a low stress area adjacent to the edge of a goaf, leaving a 5-8m small coal pillar or adopting a coal pillar-free process to make the coal pillar in a plastic yield state; then, constructing a fracturing borehole along the strike of the roadway on the ground, injecting high-pressure fluid into the main roof to build a fracture network, and actively cutting off the roof cantilever and stress transmission path; and building a combined support system composed of guniting closure, constant resistance single prop and energy absorption wood pile during underground excavation. Through arrangement optimization, roof weakening and collaborative support, the present application eliminates the stress concentration source of the wide coal pillar, realizes source treatment of rock burst, effectively controls the deformation of the roadway surrounding rock, and improves the safety of mine exploitation.

This invention discloses a soft steel friction composite damper based on a limit-triggered mechanism, belonging to the field of damper technology. Specifically, it achieves graded vibration control under all seismic ground motion levels by pre-setting a first-stage trigger gap through a limit-triggered component: under wind-induced vibration or frequent earthquakes, only the friction energy-dissipating unit undergoes relative sliding to dissipate energy, achieving early and efficient vibration control under low displacement; under the action of a fortified earthquake or a rare earthquake, the soft steel damper is triggered to enter a plastic yielding state, working together with the friction unit to dissipate a large amount of seismic energy, thus solving the problems of narrow energy dissipation range and mutual interference of traditional dampers, avoiding low-cycle fatigue damage of the soft steel unit, and the trigger displacement and energy dissipation capacity can be customized according to engineering needs. It has a compact structure, is easy to install and maintain, and is suitable for vibration reduction projects of various building and bridge structures.

Mass timber (MT) panel connectors are provided that include a first bearing portion configured to affix to a first MT structural member, a second bearing portion configured to affix to a second MT structural member, and a fuse portion extending between the second bearing portion and the first bearing portion. The first bearing portion extending from a first end towards a second end. The second bearing portion extending from the second end towards the first end. The fuse portion is configured to plastically yield when an overload is transferred between the first bearing portion and the second bearing portion. MT constructions assemblies are also provided that include structural members that are connected by a plurality of MT panel connectors.

The invention discloses a construction method for a semi-rigid energy dissipation node of a point-supported exterior wall cladding based on a composite rib material, relates to the technical field of constructional engineering, and solves the technical problem that a traditional prefabricated assembly type node is seriously damaged due to a weak structural link caused by displacement, acceleration and the like under the anti-seismic effect. Under the action of an earthquake, the high damping characteristic of the elastic supporting columns can effectively attenuate vibration energy, a multi-path energy dissipation system is formed by combining the friction and bending mechanism of the semi-rigid energy dissipation units, a hysteretic curve is full, the energy dissipation efficiency is high, the earthquake response of a main body structure is reduced, and the nodes keep rigid constraint and transmit loads during small earthquakes; in a large earthquake, flexible energy dissipation is achieved through elastic deformation of the composite rib materials and plastic yield of the energy dissipation units, brittle failure is avoided, structural safety is guaranteed, the internal force peak value of a main body structure under dynamic loads can be reduced through the semi-rigid energy dissipation design of the nodes, and the size of structural components is optimized.