32 results about "Threshold stress" patented technology

An energy absorbing device for carrying a passenger seat; the device comprises a base fixed to a vehicle; a member displaceable from base; at least one energy-absorbing arrangement interconnecting base and displaceable member. The energy-absorbing arrangement comprises a plastically deformable absorbing element in response to stresses greater than a predetermined threshold stress. In some embodiments the plastically deformable absorbing element is a helically configured ribbon having spaced-apart ribbon laps. In other embodiments the plastically deformable absorbing element is compressible, and / or extendable. A method of attenuating the acceleration applied to a passenger due to impact is disclosed; the method comprises steps of: providing an energy absorbing device fixedly attaching the base to the vehicle; fixedly attaching the passenger seat to the base; accidently applying the impact to the vehicle; displacing the displaceable member relative to the base; attenuating the effect of the impact on the passenger.

A system is provided to protect a loudspeaker (144) by controlling a level of an applied audio signal. A control signal is generated by applying an input audio signal (115) to the collective operations of a gain control system (100). The gain control system (100) uses the input audio signal (115) in conjunction with at least one parameter to derive an estimated stress associated with the loudspeaker (144). The estimated stress is compared with a protection threshold stress (127). If the protection threshold stress is exceeded, a gain applied by a gain component (134) is selectively adjusted to modify the input audio signal (115). The resulting gain-controlled audio signal (116) is employed to drive the loudspeaker (144).

In a method of determining a fatigue crack lifetime of a low-alloy steel material coming in contact with high-pressure hydrogen in a high-pressure hydrogen environment, estimate a fatigue crack acceleration starting point KmaxT of the low-alloy steel material using a crack-growth threshold stress intensity factor KIH-R obtained through a rising load test on the low-alloy steel material in a high-pressure hydrogen environment. The high-pressure hydrogen environment of the rising load test is a high-pressure hydrogen environment which has the same pressure and atmosphere as in the high-pressure hydrogen environment in which KmaxT is estimated and in which the test temperature tolerance between both environments is ±5° C.

An analysis model control unit disposes at least two component models, which are to be used in assembly of a product to be evaluated, in virtual space displayed on a screen. A virtual glove controller moves and operates component models, which are disposed in virtual space, in accordance with an input operation signal of a user by a virtual glove. When the two component models are brought into contact with each other, a model conversion unit converts them into component analysis models. A deformed structure analysis unit executes structure analysis calculations with respect to the relative movement caused along with assembly of the two component analysis models after contact so as to calculate deformation and deformation stresses. An evaluation processing unit compares the deformation stress with a threshold stress of the material so as to evaluate whether assembly can be performed without breaking the components.

The invention provides a gear bending fatigue life forecast method and a device. The gear bending fatigue life forecast method comprises the steps that a fatigue limit amendment model is built based on the surface roughness, and the fatigue limit of materials is amended according to the amendment model, the fatigue limit after the amendment is obtained; the threshold crack length is determined according to the threshold stress strength factor range and the amended fatigue limit; a fatigue crack size initiation model is created, and gear fatigue crack initiation life is forecasted based on the fatigue crack size initiation model; gear fatigue crack propagation life is forecasted based on the linear elastic fracture mechanics guidelines; according to the gear fatigue crack initiation life and gear fatigue crack propagation life, a gear bending fatigue calculation model is built, to calculate the gear bending fatigue life.

To estimate penetration behavior of hydrogen up until hydrogen content reaches saturation even if load stress on steel is equal to or higher than threshold stress. A hydrogen penetration behavior estimation device includes a first measurement data input unit adapted to input first measurement data concerning variation of hydrogen content with time up until hydrogen content in steel-to-be-estimated reaches saturation when measurements are taken by applying such stress to the steel that no hydrogen embrittlement fracture occurs; a second measurement data input unit adapted to input second measurement data concerning variation of hydrogen content in the steel-to-be-estimated with time up until the steel fractures when measurements are taken by applying such stress to the steel that hydrogen embrittlement fracture occurs; a ratio calculation unit adapted to calculate increases in hydrogen contents in an initial stage of measurement and calculate a ratio of the second measurement data to the first measurement data in terms of increase in hydrogen content; and a saturated hydrogen content calculation unit adapted to multiply saturated hydrogen content based on the first measurement data by the ratio and designate the product as saturated hydrogen content of the steel-to-be-estimated, the saturated hydrogen content being reached upon application of such stress that hydrogen embrittlement fracture occurs.

The invention relates to an alloy vermicular cast iron for a railway vehicle brake disc and a melting method thereof. The chemical composition of the vermicular cast iron, in terms of mass percentage, includes: C: 3.3-3.5%, Si: 2.3-2.5%, Mn: 0.4~0.7%, Cu: 0.6~1.0%, Mo: 0.2~0.6%, Ni: 0.6~1.0%, P≤0.07%, S≤0.02%, and the balance of Fe, among them, vermicular graphite cast iron brake disc The creep rate is ≥75%, and the pearlite content is 50%-60%. The invention can increase the stress threshold value of disc cracking and expansion caused by thermal stress concentration, and improve the mechanical properties of the railway vehicle brake disc.

The invention discloses a stress corrosion test method and a stress corrosion test device for a metal sheet pre-cracked sample. The method comprises the following steps of: fixing one end of the sample on a bearing wall, clamping the other end of the sample by using an upper clamping plate and a lower clamping plate and fixing; clamping a test section of the sample by using a corrosion environment test box; pre-estimating the initially applied stress field intensity factor according to the threshold stress field intensity factor of crack propagation of similar metal materials, wherein the pre-estimated value is greater than the threshold stress field intensity factor of the crack propagation of the metal materials; loading stress to the metal sheet sample, measuring the crack length of the sheet sample to obtain a crack stress field intensity factor, and stopping loading the stress when the crack stress field intensity factor is equal to the pre-estimated value; filling a corrosion medium in the corrosion environment test box; measuring the length of a crack at the tip of the pre-cracked sample at intervals of certain time; and measuring the crack length and the loaded stress after the crack stress field intensity factor is stabilized to obtain the threshold stress field intensity factor of stress corrosion crack propagation. The method is convenient to operate and high in measuring accuracy.

The invention relates to a continuous loading indentation stress corrosion tester and a test method therefor. The continuous loading indentation stress corrosion tester is used for researching hysteresis growth and related mechanical behaviors of material cracks and especially for researching rules of the influence produced by different stresses, environmental mediums and temperatures on crack nucleation and growth, and clearly expounds the rule and the mechanism of material invalidation under the stress-environment coupling condition. The test method comprises the following steps of 1, through contact between a pressure head and a test sample under a certain load, determining fracture toughness of a brittle material, and observing the influence produced by the environment on crack growth under the continuous loading condition, 2, determining threshold stress of hysteresis growth of cracks of the brittle material by radial cracks having certain length under a certain environmental condition, 3, in a solution medium, researching crack growth of a toughness material by indentation, and 4, observing a change of electrochemical parameters in crack growth by connection with an electrochemical workstation. The continuous loading indentation stress corrosion tester can be operated conveniently and simply, realize control of an experimental environment and a load, is especially suitable for long-term loading in different environments, has a simple structure, is convenient for operation and has a large application prospect.

The embodiment of the invention discloses an optical sheet rotating wheel, a light source system and a projection system. The optical sheet rotating wheel includes a rotating shaft and a fixed surface fixed on the rotating shaft; The outer diameter of the optical sheet is larger than the outer diameter of the fixed surface; the fixed surface includes two hollow areas, and each hollow area is equipped with a dispensing area and a beam group, and each dispensing area only passes through the beam group and the non-hollowed out area. The areas are connected and fixed, and the beam group includes at least one beam; the optical device is fixed to the fixed surface only by bonding with the dispensing area; the stiffness of the beam group in each hollow area along the radial direction passing through the center of the dispensing area The coefficient is less than the first predetermined value, so that when the branch beam group is deformed under the predetermined temperature difference, the stress on the optical device along the radial direction through the dispensing area is less than or equal to the critical value, so that the stress on the optical device is less than the stress that causes it to break. Stress critical value. The invention can provide an optical sheet rotating wheel which prevents the optical sheet from being pulled.