132 results about "Ultimate load" patented technology

The present invention relates to a sound rated floor system for inhibiting sound transmission between floors. The system includes a corrugated steel deck; a first layer of cementitious material or board or sheet applied over the corrugated steel deck; a sound insulation mat or board applied over the first layer; a second layer of cementitious material applied over the sound insulation mat or board. The floor system has an IIC rating of at least 25 and the corrugated steel deck provides at least 50 percent of the ultimate load carrying capacity under static and impact loading of the floor system with a floor deflection of at most 1/360 of the floor span.

The invention relates to a calculation method for ultimate bearing capacities of rock slopes with rock bridges, and belongs to the field of rock slope stability analysis. The method comprises the following steps of: dispersing a rock slope with rock bridges by adoption of a composite element method on the basis of a theory of the plastic ultimate analysis lower limit method; establishing a nonlinear mathematic programming model for stability analysis of rock slopes with rock bridges by taking an ultimate load and a strength reserve coefficient of the rock slope as target functions; and solving maximum values of the ultimate load and the strength reserve coefficient by using a mathematic programming optimization algorithm. According to the method provided by the invention, the plastic ultimate analysis lower limit method, a composite element method dispersion technology and a mathematic programming measure are combined to establish a rock slope ultimate bearing capacity solution method which not only can simulate the continuous media characteristics of the rock bridges, but also can simulate the non-continuous media characteristics of rock blocks. The method provided by the invention has the characteristics of being clear in concept and high in calculation precision, and can be applied to the analysis of bearing capacities of the rock bridges in rock slopes.

The invention discloses a high-frequency high-specific pressure long-stroke temperature-controllable reciprocating friction test device. The high-frequency high-specific pressure long-stroke temperature-controllable reciprocating friction test device is characterized in that a tested unit comprises an upper test piece and a lower test piece which are arranged in a splitting way, wherein the lower test piece is supported on a roll ball; the upper test piece and a pressure transmitting piece are arranged in a reverse T shape; a mating test piece positioned between the upper test piece and the lower test piece is in surface contact with the upper test piece and the lower test piece; a reciprocating motion driving unit is a crank-slider mechanism driven by a motor; a loading unit is a loading lever capable of carrying out multilevel incremental loading; and a friction coefficient measuring unit is a force sensor taking the lower test piece as a tested piece. In the invention, the reciprocating motion frequency can reach 40 Hz, the reciprocating motion stroke can reach 115 millimeters and the contact surface specific pressure can reach 40 MPa; the measurement of the friction coefficients and the real-time temperature of parts can be realized; and the ultimate loads of the parts can be measured.

The invention discloses a safety evaluation method for the shortcomings of a high temperature production device or part, comprising the steps as follows: a creep strain-time curve of the material of the high temperature production device or part at a particular temperature is obtained, and an isochronous stress-strain curve corresponding to the particular time is established based on the creep strain-time curve; a failure assessment curve chart related to time is established; and a parameter Kr which can determine and reflect the cracking failure degree of the part and a parameter Lr which can determine and reflect the ultimate load failure degree of the part are counted; and finally the parameters(Kr and Lr) are put into the failure assessment chart as state points for comparing so as to determine the failure assessment point and judge the safety of the failure assessment point. The method can be used for analyzing the safety of the shortcomings during the production process and the use process of the high temperature production device or part, thereby avoiding unnecessary maintenance and premium, and further increasing the rationality of making maintenance plans for high temperature production devices.

The present invention is directed at providing a numerical analysis method to determine the damage sustained on a structure based upon the physical dimensions of a the structure, the structure's design wind speed and the forces applied during an event such as a hurricane or man made event. The method includes the steps of creating a timeline by which event forces can be plotted and compared to an ultimate load of the structure, individual loads placed upon the structure as well as a sum of the individual loads placed upon the structure. By using this method, the user is able to identify the time at which the ultimate load of the structure was exceeded and the maximum individual and total loads occurred. The method further identifies the time when the structural failure likely initiated and the time by which the structural failure was likely complete. The method further provides a determination of the percentage individual load at the time the ultimate load is breeched as well as a time step of forces applied to the structure throughout the course of the event.

The invention provides a piston cooling nozzle control method and system, relates to the technical field of vehicles, and aims to solve the problem that the oil consumption of a vehicle is increased due to the too low temperature of a piston. The piston cooling nozzle control method comprises the following steps: acquiring the current rotational speed and the current load of an engine in the vehicle during heat-engine running of the vehicle; opening a piston cooling nozzle when the current rotational speed of the engine is higher than or equal to the ultimate rotational speed and when the current load of the engine is higher than or equal to the ultimate load; and closing the piston cooling nozzle when the current rotational speed of the engine is lower than the ultimate rotational speed and when the current load of the engine is lower than the ultimate load, wherein the ultimate rotational speed is set to the rotational speed of the engine acquired when the piston of the engine reaches the limit of heat load and the ultimate load is set to the load of the engine acquired when the piston reaches the limit of heat load. The piston cooling nozzle control method provided by the invention is used for lowering the oil consumption of the vehicle.

The invention relates to a calculation method for ultimate strength and fatigue strength of a yaw bearing connecting bolt of a wind turbine. Mesh generation and assembling are separately performed on three-dimensional geometrical models of devices on a load transfer path related to the bolt by use of finite element software, so as to establish a finite element model, so that the load transfer path is completed and is consistent with the reality. The devices on the load transfer path at least comprise a gear box body, a main frame, a tower drum, a yaw bearing and a yaw bearing connecting bolt. Limit loads of different working conditions are applied to the models, and the models are submitted to finite element analysis software to be solved, so as to obtain the ultimate strength and fatigue strength of the yaw bearing connecting bolt of the wind turbine. Through adoption of the method, the complete load transfer path is realized, the accuracy of bolt security coefficient is improved, and the operation reliability of the wind turbine is improved.

The invention relates to a high-level assessment method for defects of a welding joint area at a piping safety end of a pressure vessel of an AP1000 nuclear reactor. The method comprises the following steps of: characterizing the detected dimensions of unpenetrated circumferential inner surface defects; establishing a failure assessment graph, wherein the failure assessment graph comprises the family of the failure assessment curves of the unpenetrated circumferential inner surface defects in the different dimensions, which are acquired on the basis of three-dimensional finite element calculation; selecting the failure assessment curves according to the dimensions of the defects; based on the three-dimensional finite element calculation, calculating the family of the curves that stress intensity factors change along an extra resultant bending moment at the deepest points of the unpenetrated circumferential inner surface defects in the different dimensions; determining the stress intensity factors according to the resultant bending moment and the dimensions of the defects; calculating a specific breaking strength parameter Kr; based on the three-dimensional finite element calculation, acquiring the family of the ultimate load bending moment curves of the unpenetrated circumferential inner surface defects in the different dimensions; determining ultimate load bending moments according to the dimensions of the defects; calculating a load ratio parameter Lr; and marking a calculated coordinate (Lr, Kr) on the failure assessment graph, and judging whether falling into an area which is encircled by the selected failure assessment curves, a vertical end line and coordinate axes or not.

The invention discloses an intelligent optimization design method for a low-wind-speed wind turbine generator wind wheel, which comprises the following steps: selecting blade aerodynamic configurationparameters as optimization variables, calculating a blade power coefficient and a thrust coefficient according to variable values, and constraining Cpmax and Ctr; selecting the structural layer design parameters as optimization variables, calculating the mass center, the rigidity distribution and the inertia structural performance of each section of the blade, and forming a blade model by combining the aerodynamic configuration data; Adding the blade model into the complete machine model, and calculating the annual generating capacity of the complete machine; calculating and counting the dynamic load to obtain the maximum limit load of the blade root, the fatigue load and the blade clearance, and constraining the blade clearance; and finally, selecting a reasonable range of each optimization variable, and searching a blade design optimal solution by taking the maximum annual generating capacity and the minimum blade root load as optimization objectives. The optimized blade can ensurethe structural strength, the annual generating capacity is increased, the blade root load is reduced, the blade efficiency is improved, the cost is reduced, and the competitiveness is higher.

The invention discloses a plastic limit analysis upper-bound method for ultimate bearing capacity of a masonry retaining wall, relates to a plastic limit analysis method for solving ultimate bearing capacity of masonry retaining, and belongs to the technical field of side-slope protection projects. The method comprises the steps of taking the masonry retaining wall as a research object; simulating mechanical properties of masonry by adopting a rigid block element based on a theory of the plastic limit analysis upper-bound method; establishing external force overload conditions by taking a displacement rate of the centroid of the block element as an unknown variable and introducing a Rankine earth pressure theory; establishing a kinematically admissible velocity field meeting rigid block unit and mortar layer surface deformation compatibility conditions, plastic flow constraint conditions, internal and external power equality conditions and velocity boundary conditions; building a nonlinear mathematic planning model for solving the ultimate bearing capacity of the masonry retaining; and solving a minimum value of an ultimate load by using an optimization algorithm. The method has the characteristics of definite concept, high calculation precision and the like, and can be applied to the analysis of the bearing capacity of the masonry retaining wall.

The invention discloses a method that combination of a test and calculation is utilized, and structure performance evaluation of a horizontal shaft wind turbine blade is carried out under the static force loading function. Compared with the existing method that performance evaluation is carried out by only using a blade test-bed static force test, the static force test result correcting method is capable of accurately estimating showed structural responses when limit load or other static load is borne in operation. The static force test result correcting method is composed of the following parts: static force of the blade on a test test-bed, numerical simulation during the process of a test-bed static force test; correlation analysis of the test and the calculation, impact analysis of centrifugal load to blade structure responses under the actual operating conditions, correction of impacts to test results. Due to the fact that the impact analysis of the centrifugal load to the blade structure responses is introduced by the static force test result correcting method, and correction is carried out on the test, and the shortage that impacts of the centrifugal load to the blade structure responses can not be reflected by the test-bed static force test can be made up, and accuracy of the structure performance evaluation is improved.

The invention relates to a displacement release type anchor head device comprising an anchor rod, a loosing ring and a clamp nut. The displacement release type anchor head device is characterized by also comprising a stress release device and a protective device, wherein the stress release device is arranged between the loosing ring and the clamp nut; the protective device is arranged on the periphery of the stress release device; the axial compression strength of the stress release device is lower than that of the anchor rod; and a strain type device is used as the anchor head so that the anchor rod properly internally moves along with a rock mass inside the loosing ring by properly releasing a certain amount of space through the deformation of the anchor head when external force acting on the anchor rod exceeds the self strength of the anchor rod, the anchor rod can still work under the action of ultimate load, and the normal use of a tunnel can be ensured.

A system for extending and retracting a folding trailer. The trailer has a movable top extending from a base, and a plurality of extendible supports mounted on the base and connected to the top. A drive including an electric motor extends and retracts the extendible supports in unison to extend and retract the top. A controller is provided for the drive, the controller having a motor load monitor having both an ultimate load detector and a calculated load detector. In extending and retracting the top, the load of the electric motor is regularly monitored, and is first compared with an ultimate load threshold. The motor is stopped if the ultimate load threshold is met or exceeded. The monitored load is also compared with a stall load threshold, and the motor remains in operation until the stall load threshold is met or exceeded.

The invention relates to the field of aircraft high-lift system tests, in particular to a high-lift system whole-aircraft loading dynamic test method, so as to solve the problem that test results of the high-lift system design at present are incorrect. The high-lift system whole-aircraft loading dynamic test method loads an aerodynamic load on aerofoils of a high-lift device under the condition of a predetermined angle step by step through a loading actuator, judges whether a fault recurs during the process of loading the aerodynamic load to a limit load step by step under the predetermined angle so as to obtain magnitude of the loading load when the aircraft fails, can truly simulate the real flying condition of the aircraft high-lift system, confirms that the stress conditions of the high-lift system, the relevant high-lift device, wing boxes and the like in whole-aircraft tests are consistent to that of the same in the air, and eliminates major flight failures of the aircraft; in addition, the high-lift system whole-aircraft loading dynamic test method is a breakthrough of the dynamic driving/coordinated loading technology, and changes the severe shortages and deficiencies of the previous test methods essentially.

The invention relates to a wind turbine blade static analysis method. The method is characterized by comprising steps: a blade model narrowed with equal proportion is adopted for carrying out static force test and static force calculation, material performance of the blade is corrected through correlation analysis on the two, the corrected material data are applied to a blade which is analyzed or estimated actually, the actual blade is calculated, and static parameter of the blade under the effect of concerned load. As for the researched and designed wind turbine blade, the method can be used for accurately predicting various structural response data of the blade under the effects of limit load and other static load, and the response situations of the prior blade under the effects of the static load can be estimated. According to the method, at the beginning when the blade is designed, various structural response data of the blade under the effects of limit load and other static load can be accurately mastered, structure optimization can be carried out in the case of design, and the method can also be applied to static estimation on a large blade which is already produced or in operation.

The invention belongs to the technical field of electric power and relates to a transformer winding short circuit fault damage point locating method. The method includes the following steps that: step1, the three-dimensional field-circuit coupled electromagnetic field mathematical model of a transformer is established, and the voltage constraint condition of a short-circuit process is a directlyintroduced, and an electromagnetic field and short-circuit current are solved simultaneously; step 2, the axial vibration and radial stability of the winding of the transformer are analyzed; and step3, a branching type unstability theory is introduced to establish the finite element calibration model of the transformer, and the buckling modality of the coil of the winding under a radial limit load force and different short-circuit load forces can be obtained through buckling analysis with the effects of struts and spacers considered, so that the short-circuit fault damage point of the transformer can be found out. With the method of the invention adopted, the calculated limit load of the winding is closer to an actual working condition under the condition that the effects of the struts and spacers are fully considered, and the damage degree and deformation displacement of the winding can be effectively judged, and the specific damage fault location of the winding can be determined.

The invention relates to a finite element modeling method for a hub of a megawatt wind generating set, and belongs to the technical field of wind power generation. The technical scheme comprises the following steps of: modeling a 1/3 model of the spherical hub according to the symmetry of the spherical hub to form a finite element model of the 1/3 model, and rotating finite element model of the 1/3 model to form a finite element model of the whole hub; and performing calculation and strength checking by utilizing the rotational symmetry of the spherical hub, wherein the rotational symmetry refers to that hub stress nephograms formed by applying a load on one blade and applying a load on another blade can be completely superposed after rotating 120 or 240 degrees. The method has the advantages that: for analysis on the ultimate strength of the hub, all ultimate load working conditions can be taken into account, and limitation on the condition that a certain load component reaches maximum is avoided, so that calculation reliability and comprehensiveness are improved, and a calculated amount is decreased; and for analysis on fatigue strength, the workload of calculation is greatly reduced, and working efficiency is improved.

The invention provides a dynamic design method of initial support of tunnel based on deformation structural method. Including: the construction of a beam-spring model of surrounding rock and the initial support structure, the deformation data of initial support are obtained, Calculate the load, determine the structural internal force of the initial supporting structure, determine the safety factorof the initial supporting structure according to the calculation of the structural internal force, evaluate the safety of the initial supporting structure according to the safety factor, and completethe design of the initial supporting structure of the tunnel until the initial supporting structure meets the safety requirements. The invention determines the structural internal force of the initial support through the calculation load of the support deformation, which is high in efficiency, convenience and good in timeliness. It provides the basis for changing the design parameters of the initial support, realizes the dynamic design of the initial support, and realizes the quantification of the initial support combined with the safety factor. The ultimate deformation of the initial supportcan be easily predicted based on the time history curve of the node displacement, so that the ultimate load of the initial support can be predicted.

The present invention relates to a leak before burst (LBB) analysis method based on a failure assessment diagram (FAD). The method comprises the following steps: (a) service state analysis; (b) initial crack selection; (c) load analysis; (d) line elastic stress intensity factor (SIF) calculation; (e) ultimate load analysis; (f) evaluation point coordinate calculation; (g) FAD selection; (h) evaluation point drawing; (i) elastoplastic SIF calculation; (j) J-integral calculation; (k) calculation and fitting of the J-integral of different cracks; (l) calculation of the structural failure criticalcrack size; (m) calculation of the structural critical leakage crack size; and (n) LBB criterion evaluation. According to the method provided by the present invention, based on the FAD theory, defects that the theoretical basis of elastoplastic analysis in the existing norms is insufficient, the existing J-integral calculation manual has a limited application scope, the finite element modeling analysis process is complicated, and the processes for calculating the structural failure critical crack size and the structural critical leakage crack size are complicated, and the like are overcome, and a FAD-based LBB analysis basis is provided.

The invention discloses an airplane gravity center envelope calculation method. The method comprises the steps that original parameters of an airplane are input, and the loading condition and the initial gravity center position are given; according to the aircraft aerodynamic model, the undercarriage model, the engine model and the full-aircraft flight mechanical model, calculating full-aircraft aerodynamic force and aerodynamic moment of the aircraft, and finishing trimming; the load weight and the gravity center position are dispersed; judging whether the aircraft can normally cruise and flyand normally take off and land or not; and then introducing static stability margin constraint and wing and horizontal tail limit load constraint under the condition of large aircraft load under thecondition of minimum horizontal flight speed to obtain a relation graph of front and rear gravity center limits and aircraft flight weight. According to the method, discretization processing is carried out on the load gravity center coordinate point, the flight process and the take-off and landing process of the aircraft are simulated, the gravity center of the aircraft is accurately calculated, the process is simple, and calculation is convenient.

The invention discloses a crankshaft fatigue limit load prediction method based on an improved stress field intensity method, and the method comprises the steps: taking two crankshafts with the same material and different structures, wherein the fatigue limit load of a first crankshaft is known, and the fatigue limit load of a second crankshaft is unknown; analyzing the stress state of the first crankshaft under the action of the fatigue limit load, acquiring the stress distribution of the first crankshaft under the action of the limit load, and calculating the weight function of the first crankshaft, thereby determining the field diameter value of the first crankshaft; applying1000 N.m bending moment load to the second crankshaft, and obtaining the field diameter value of the second crankshaft and the field intensity value under the action of the bending moment load through relative stress gradient correction; and predicting the fatigue limit load of the second crankshaft. According to the method, the fatigue limit loads of crankshafts of the same material and different structures can be predicted more accurately, and the influence of the fillet radius of the crankshafts on the prediction result can be greatly reduced.

The invention provides an airplane front landing gear outer cylinder support rod connector traction takeoff static force testing method which comprises the following steps: according to a bearing situation of an outer cylinder support rod connector, confirming a key stress part and a strain piece pasting position of the outer cylinder support rod connector; detecting a strain piece, and ensuring that the survival rate of the strain is 95% or greater in loading measurement; manufacturing a sample part of the outer cylinder support rod connector, mounting the sample part on a clamp, and exertinga load; implementing loading testing, including pre-testing and official testing, exerting a limit load of 60% from a limit load of 5% step by step in pre-testing, implementing 100% limit load testing once and implementing 150% extreme load testing once in official testing, exerting loads according to the 5% limit load step by step in the 100% limit load testing, exerting loads for the former 100% limit loads according to 5% limit loads step by step and exerting loads for the later 50% limit loads according to 2% limit loads step by step in the 150% extreme load testing, and judging that theouter cylinder support rod connector is qualified in the static force testing if the sample part is not damaged in the testing. By adopting the static force testing method provided by the invention, the fatigue properties and the service lives of partial structures are verified in advance by testing test parts, and the research cost is reduced.