33results about How to "Meet the rigidity requirements" patented technology

The present invention provides a complete scissor-like double-layer annular truss extendible antenna mechanism. The mechanism comprises an inner layer annular truss component, an outer layer annular truss component and N inner and outer layer connection truss components; the inner layer annular truss component and the outer layer annular truss component both include N extending units; two common flower discs are connected between adjacent extending units; the inner and outer layer connection truss components are concentrically arranged; two upper and lower flower discs at each side of the inner layer extending units are connected with the corresponding two upper and lower outer layer flower discs at each side of the outer side layer extending units respectively through one inner and outer layer connection truss component to form a double-layer annular truss; and the distance between the length of the rod pieces at the same position of the inner and outer layer extending units and a flower disc rotation secondary axis and a center line satisfies a special proportional relation, and the ratio of the inner layer and the outer layer is (1-sin(180 / N)) / (1+sin(180 / N)). The complete scissor-like double-layer annular truss extendible antenna mechanism is high in rigidity, simple in structure and high in reliability, and can be applicable to a communication satellite, a space station and a space probe.

The invention discloses a device and method used for measuring axial bolt relaxation in consideration of joint surface characteristics, which belongs to the field of mechanical manufacturing and structural mechanics. A bolt bar passes through upper and lower connectors, and contact surfaces have specific size and surface data. A pressure sensor is used to measure the attenuation of the bolt clamping force. An eddy current displacement sensor is used to measure displacement between the contact surfaces. Three-dimensional topography scanning is used to measure the surface three-dimensional data. A tensile testing machine is used to carry out cyclic tensile test and simulate the bolt conditions. The axial clamping force and axial displacement are transmitted to a computer for recording and processing through a data acquisition system. Axial bolt relaxation characteristics are acquired by analysis and processing several kinds of data. According to the invention, the connection characteristic of an axial part is ensured; the influence of a fixed joint surface on bolt relaxation is considered; and the bolt relaxation test precision is improved.

The invention provides a double-layer annular truss antenna mechanism based on passive drive and relates to double-layer annular truss type expandable antenna mechanisms. The problems that an existing large-caliber single-ring annular truss antenna is small in rigidity, the use rigidity requirement can not be met, an existing annular truss antenna mechanism is complex in drive structure and large in weight, inhaul cables are prone to be twisted after being used for unfolding the mechanism, and the unfolding reliability is low are solved. The double-layer annular truss antenna mechanism comprises multiple inner and outer truss foldable unit modules, multiple inner transition folding assemblies and multiple outer transition folding assemblies. Each inner and outer truss foldable unit module comprises an inner folding unit module, an outer folding unit module and two inner and outer connection truss assemblies. Inner supporting vertical rods and outer supporting vertical rods which are opposite are connected through the inner and outer connection truss assemblies. After the inner and outer truss foldable unit modules are unfolded, an inner and outer double-layer annular truss polyhedron is formed. The double-layer annular truss antenna mechanism is used for a satellite, a space station and a space probe.

The invention discloses a measurement method for the influence of residual stress on bolt connection structure clamping force attenuation. A device for realizing the method includes: a tensile testingmachine, a lower connecting piece, a nut, an eddy current displacement sensor, an upper connecting piece, a bolt, a pressure sensor, and a corresponding sensor data acquisition system and a computer,a 3D surface morphology measurement instrument, a digital display torque wrench, a vibration table, and an X ray residual stress tester. The 3D surface morphology measurement instrument is employed to acquire the three-dimensional morphology of a contact surface, vibratory stress relief process and the X ray residual stress tester are employed to acquire bolts that are made of a same material andhave different levels of residual stress, the tensile testing machine, the pressure sensor and the displacement sensor are combined to collect the data under the circumstances of a same pretighteningforce and specific amplitude circulating alternating load. The method can achieve quantitative analysis of the relationship between the two structures, provides the experimental basis for further study of the influence of residual stress on bolt connection structure clamping force attenuation, and has the characteristics of simple and quick operation and accurate measurement.

A cable-stayed stretch-draw annular expandable antenna mechanism relates to an expandable antenna mechanism and solves the problem that an existing annular truss mechanism has a decrease in stiffnesswith an increase in the diameter of an antenna, cannot meet the stiffness requirements and has a complicated driving mechanism, a large weight and low expansion reliability. The cable-stayed stretch-draw annular expandable antenna mechanism comprises a plurality of cable-stayed stretch-draw expandable unit modules. Each of the cable-stayed stretch-draw expandable unit modules comprises a first expandable unit module and a second expandable unit module which are connected together. The plurality of first expandable unit module and the plurality of second expandable unit modules are arranged alternately and connected together to form a cable-stayed stretch-draw annular truss after expanded. The cable-stayed stretch-draw annular expandable antenna mechanism is good in reliability, compact instructure, light in weight, easy to drive, high in stiffness after fully expanded, meets the requirements for a large-diameter antenna, and is applied to a communication satellite, a space station anda space detector.

The invention discloses a test device for measuring double bolt relaxation under tangential alternating load, which belongs to the field of mechanical engineering and mechanics. The device has the advantages that the structure is simple; the price is low; the bolt relaxation can be reflected through measuring attenuation of axial tightening forces of the double bolts; influences on the bolt relaxation by the interaction between the double bolts and the joint surface tangential displacement changes are also considered; the test precision for measuring the tangential relaxation of the double bolts and the data accuracy are improved; and the sensitivity is high, and the response speed is quick. The device comprises an upper connector, pre-buried strain gauge bolts, an eddy current transducerand a lower connector. The pre-buried strain gauge bolts with higher precision are adopted, and the data can be outputted in real time and saved; and the high-precision loading and the frequency control on a tensile test machine are also combined, and the data accuracy is ensured. A large amount of accurate data are provided for follow-up analysis, and the measurement precision is improved. The device reflects the interaction between the double bolts through the pre-tightening force changes and different relaxation curves of the double bolts during tightening and loading processes.

The invention discloses a hybrid scissors-forks type extensible antenna mechanism of a double-layer ring-shaped truss. The hybrid scissors-forks type extensible antenna mechanism mainly comprises an inner-layer ring-shaped truss assembly, an outer-layer ring-shaped truss assembly, a central fixed scissors type connecting assembly and a central movable scissors type connecting assembly, wherein theinner-layer ring-shaped truss assembly comprises n inner-layer folding and stretching units; the outer-layer ring-shaped truss assembly comprises 2n outer-layer folding and stretching units; the central fixed scissors type connecting assembly comprises n fixed scissors type folding and stretching units and n / 2 central movable scissors type folding and stretching units; upper and lower four inner-layer disk chucks at the two sides of the inner-layer folding and stretching units and upper and lower six outer-layer disk chucks of corresponding two outer-layer folding and stretching units definethe double-layer ring-shaped truss mechanism through two central fixed scissors type folding and stretching units and one central movable scissors type folding and stretching unit. The hybrid scissors-forks type extensible antenna mechanism is simple in implementation way, is high in reliability, has the advantages of being flexible in movement and relatively great in folding, and can be applied to a communication satellite, a space station and a space detector.

The invention provides a high-folding-unfolding-ratio double-layer annular unfoldable antenna mechanism based on straight quadrangular units. The high-folding-unfolding-ratio double-layer annular deployable antenna mechanism comprises a plurality of same straight quadrangular units, each straight quadrangular unit is formed by fixedly connecting an upper-layer unfoldable module and a lower-layer unfoldable module which are in mirror symmetry through four connecting rods, and the plurality of adjacent straight quadrangular units are networked; every two adjacent straight quadrangular units share a first faceplate, a first connecting block and a first connecting rod. The sequential connection lines of the central points of all the first connecting rods form a regular polygon, and a third faceplate and a fourth faceplate on the same layer of every two adjacent straight quadrangular units are connected through a series chain comprising three parallel revolute pairs and two equal-length rods. The mechanism has the beneficial effects that joint parts are connected through revolute pairs, so that the cold welding phenomenon of the mechanism during the moving process is reduced; the straight quadrangular units have the advantages of being high in stability, large in folding-unfolding ratio and high in rigidity and being easy to assemble.

The invention discloses a tangential single bolt relaxation measuring device and method based on modal parameter characterization, belonging to the field of mechanical manufacturing and structural mechanics. The measuring device includes a bolt tensile test machine, a tangential specimen, a bolt data acquisition system, and an LMS vibration test system. The method includes the following steps: obtaining a relaxation law curve of a bolt through the tensile test machine, the tangential specimen and the bolt data acquisition system; getting feature stages of bolt relaxation; using the LMS vibration test system to measure the modal parameters of different relaxation stages; and finally, using the modal parameters to characterize the relaxation characteristics of the bolt. According to the device and the method, the modal parameters are acquired by changing the vibration frequency to different values and loading loads to characterize the bolt relaxation characteristics under the influence of various parameters. The invention relates to an improved tangential connection specimen, which ensures that the connection characteristics and relaxation of bolts can be measured, and improves the accuracy of bolt relaxation measurement. The invention further presents a method of characterizing the relaxation of tangent single bolts with modal parameters.

The invention relates to an over-constrained shear fork-type double-layer annular truss deployable antenna mechanism. The over-constrained shear fork-type double-layer annular truss deployable antenna mechanism comprises an inner-layer annular truss assembly, an outer-layer annular truss assembly and 2N inner and outer-layer connection truss assemblies; the inner-layer annular truss assembly includes N inner-layer folding and unfolding units; adjacent inner-layer folding and unfolding units are connected with each other through two common inner-layer disc chucks, so that the inner-layer annular truss assembly can be formed; the outer-layer annular truss assembly includes N outer-layer folding and unfolding units; adjacent folding and unfolding units are connected with each other through two common outer-layer disc chucks, so that the outer-layer annular truss assembly can be formed; and two inner-layer disc chucks at the upper part and lower part of the same side of each of inner-layer folding and unfolding units are connected with four outer-layer disc chucks of a certain outer-layer folding and unfolding unit through two inner and outer-layer connection truss assemblies, so that the shear fork-type double-layer annular truss deployable antenna mechanism can be formed. The shear fork-type double-layer annular truss deployable antenna mechanism of the invention has good manufacturing process, high rigidity and large folding ratio.

The invention discloses a load projection and mapping method for importing press forming information to a finite element simulation model. The method includes the following steps that node force information of a sheet is positioned, projected and mapped to a die profile grid twice during press forming; load information on the die profile grid is transmitted to a model tetrahedron unit, and node action forces of the sheet are directly applied to a die so as to replace the action of the sheet on the die. The method achieves force transmission between the sheet and the die during press forming, has an important theoretical guiding significance and application value in vehicle press forming die structural analysis, belongs to the technical field of vehicles, solves the problem of how to quickly and accurately project and map the press forming information of the sheet to the finite element simulation model in the prior art, and achieves load projection and mapping between node action forces of different grid models.

The invention discloses an expandable antenna mechanism of a torsion spring driven shears-fork annular truss. The mechanism comprises N folding and unfolding units with completely same structure, and the adjacent folding and unfolding units are connected by shared upper and lower flower discs to form a polygonal annular truss. Each folding and unfolding unit comprises two shears-fork rods, two groups of torsion spring driving assemblies, four connecting rods and four flower discs. All rotating pair axes on the shears-fork rods and the connecting rods in the same folding and unfolding unit are parallel. The mechanism has the characteristics of high rigidity, flexibility in motion and large folding ratio; and by adopting torsion spring driving, the whole mechanism is fast in unfolding and quick in response, and can be applied to communication satellites, space stations and space detectors.

The invention belongs to the technical field of aerospace appliances and equipment, and particularly relates to a large cable-strut truss type deployable antenna mechanism. The cable-strut truss typedeployable antenna mechanism comprises a plurality of cable-strut truss type deployable units, wherein the plurality of deployable units are connected through connecting longitudinal rods to form thecable-strut truss type deployable antenna mechanism; each deployable unit comprises first deployable assemblies and a second deployable assembly arranged between the first deployable assemblies, the first deployable assemblies and the second deployable assemblies are triangular support bodies, and the first deployable assemblies and the second deployable assemblies are connected through third torsion spring connectors to form the deployable units. The large cable-strut truss type deployable antenna mechanism is good in reliability, compact in structure, good in rigidity after being completelyunfolded, capable of meeting the use requirement of a large space antenna and suitable for a satellite space folding and unfolding mechanism and the like.

The invention discloses a scissor-like frame linkage over-constraint double-layer annular truss deployable antenna mechanism which mainly comprises an inner annular truss component, an outer annular truss component and an inner and outer truss connecting component. The inner annular truss component comprises n inner folding and unfolding units, two adjacent inner folding and unfolding units are connected through an upper inner flower disc and a lower inner flower disc which are shared, the outer annular truss component comprises 2n outer folding and unfolding units, two adjacent outer foldingand unfolding units are connected through an upper outer flower disc and a lower outer flower disc which are shared, the inner and outer truss connecting component comprises 2n middle folding and unfolding units, the inner annular truss component and the outer annular truss component are concentrically arranged, and the upper inner flower disc and the lower inner flower disc of each side of each inner folding and unfolding unit are connected with the upper outer flower disc and the lower outer flower disc of each side of the corresponding outer folding and unfolding unit through the middle folding and unfolding units. The antenna mechanism has the advantages of high stiffness and reliability and simple structure and is applied to communication satellites, space stations and space detectors.

The invention discloses an anchorage type counterforce frame testing device applicable to underground space structures, and relates to the technical field of structural tests. The anchorage type counterforce frame testing device comprises a poured concrete steel square tube upright column, a counterforce frame anchorage system, a tensioner and a stress gauge. The poured concrete steel square tubeupright column is fixedly embedded in a foundation, the tensioner is used for adjusting the tension degree of a draw bar of the anchorage system, and the stress gauge is used for monitoring stress ofthe draw bar. The anchorage type counterforce frame testing device has advantages that the stiffness level of counterforce frames can be greatly upgraded, the load application safety guarantee level can be reinforced, experimental spaces can be effectively saved, and the anchorage type counterforce frame testing device has an excellent application prospect for carrying out structural tests in limited experimental spaces on basement first floors.

The invention relates to a scissors fork linkage type double-layer circular truss unfoldable antenna mechanism. The scissors fork linkage type double-layer circular truss unfoldable antenna mechanism includes an inner-layer circular truss assembly, an outer-layer circular truss assembly and N inner and outer layer connection truss assemblies; each of the inner-layer circular truss assembly and the outer-layer circular truss assembly includes N folding and unfolding units, wherein adjacent folding and unfolding units are connected through two disk chucks; after being unfolded, each of the inner-layer circular truss assembly and the outer-layer circular truss assembly is a multi-faced circular truss structure; the inner-layer circular truss assembly and the outer-layer circular truss assembly are arranged concentrically; four disk chucks between the inner-layer circular truss assembly and the outer-layer circular truss assembly, which are located in a vertical plane, are connected together through one inner and outer layer connection truss assembly; the structure form and connection mode of the inner-layer folding and unfolding units are similar to the structure form and connection mode of the outer-layer folding and unfolding units; outer-layer rods are longer than inner-layer rods; and the length difference value of the outer-layer rods and the inner-layer rods can be designed according to the specific aperture and folding ratio of the unfoldable antenna. The scissors fork linkage type double-layer circular truss unfoldable antenna mechanism of the invention has the advantages of high rigidity, structural simplicity and high reliability. According to the scissors fork linkage type double-layer circular truss unfoldable antenna mechanism, the expansibility of modules is high, and the number of the modules can be changed randomly according to the requirements of the aperture of the antenna and the sizes of units. The scissors fork linkage type double-layer circular truss unfoldable antenna mechanism can be applied to communication satellites, space stations and space detectors.

The invention relates to a scissor-type deployable antenna mechanism based on rolling hinges. The scissor-type deployable antenna mechanism comprises a scissor-type deployment unit and a supporting and driving unit, wherein the supporting and driving unit comprises a supporting column and a sliding disc, and the scissor-type deployment unit comprises a first-stage deployment unit and a second-stage deployment unit; the first-stage deployment unit comprises two identical first rod pieces, rolling hinges with a sliding groove and rolling hinges with a boss; and the second-stage deployment unit comprises two identical second rod pieces, rolling hinges with a sliding groove and rolling hinges with a boss. When the supporting and driving unit and a sleeve type inhaul cable unit are in a deployed state, the sliding disc is attached to a base plate of the supporting column, the sleeve is locked through an internal locking mechanism, the inhaul cable is in a tightened state, the stability is good after the structure is locked, and the using rigidity requirement of the large-diameter deployable antenna in space can be met.

The invention relates to a light-weight high-strength helicopter tail door structure, and belongs to the field of lightweight design of helicopter structures. A traditional tail door is of a metal frame beam structure, the labor amount is large, and a large weight cost is required to pay for meeting the design required strength. The invention provides the light-weight high-strength helicopter taildoor structure. The structure is mainly composed of an inner layer floor, an outer layer bottom skin and a middle layer composite material stiffened plate; and the composite material stiffened plateis a plate with rib structures, each rib structure is composed of a concave-convex structure of the plate, the extending directions of the rib structures are longitudinal, and the rib structures are symmetrically distributed on the left and right of a symmetry axis of a helicopter body. The light-weight high-strength helicopter tail door structure can meet the stiffness and strength requirement ofdesigning to pass oversize vehicles while the weight is reduced by 20%, and the structure has the characteristics of being light in weight and high in strength.

The invention relates to a conical single-layer annular truss deployable antenna mechanism driven by torsional springs. The conical single-layer annular truss deployable antenna mechanism comprises Nisosceles trapezoid folding and unfolding units, wherein N>=3. The structure of the isosceles trapezoid folding and unfolding units are completely the same, and the adjacent folding and unfolding units are connected through shared inclined rods and upper and lower corner hinges to form a regular N-polygon annular truss; and each trapezoidal folding and unfolding unit comprises chord members, a crank rod piece, a torsion spring driving assembly, an inclined rod, a corner sliding block assembly and a corner hinge, and the chord members comprise the upper chord member and the lower chord member.According to the annular truss structure with the taper, the overall structural rigidity is not lower than that of a columnar annular truss structure under the conditions of the same caliber and the same mass, the rigidity is high, and the using rigidity requirement of a space large-caliber deployable antenna can be met.

The invention relates to a horizontal type VPX module debugging device comprising a horizontal type VPX module mounting rack, a VPX module interface board power supply and control adapter board and aconnecting cable, wherein the horizontal type VPX module mounting rack comprises bottom plate and an open type top plate, four cushion blocks are installed below the bottom plate and used for supporting the bottom plate, a pair of guide rails, an upper cross beam and a lower cross beam are installed between the bottom plate and the open type top plate, the guide rail is used for guiding insertionand extraction of the VPX module and fixing an upper guide pin and a lower guide pin thereof, and the upper and lower cross beams and built-in nut strips are used for mounting and fixation of the guide rails and locking and starting of an upper handle and a lower handle of the VPX module; the VPX module interface board is vertically mounted on the rear portion of the horizontal type VPX module mounting rack; and the power supply and control adapter board is horizontally mounted on the bottom plate of the horizontal type VPX module mounting rack. According to the horizontal type VPX module debugging device in the invention, horizontal placement of the VPX module is realized, one-time insertion and extraction is only required for one-time debugging, operations such as index tuning, fault removal, component replacement and the like during debugging are facilitated, and the mechanical service life of the VPX interface is guaranteed.

A cable-stayed stretch-draw annular expandable antenna mechanism relates to an expandable antenna mechanism and solves the problem that an existing annular truss mechanism has a decrease in stiffnesswith an increase in the diameter of an antenna, cannot meet the stiffness requirements and has a complicated driving mechanism, a large weight and low expansion reliability. The cable-stayed stretch-draw annular expandable antenna mechanism comprises a plurality of cable-stayed stretch-draw expandable unit modules. Each of the cable-stayed stretch-draw expandable unit modules comprises a first expandable unit module and a second expandable unit module which are connected together. The plurality of first expandable unit module and the plurality of second expandable unit modules are arranged alternately and connected together to form a cable-stayed stretch-draw annular truss after expanded. The cable-stayed stretch-draw annular expandable antenna mechanism is good in reliability, compact instructure, light in weight, easy to drive, high in stiffness after fully expanded, meets the requirements for a large-diameter antenna, and is applied to a communication satellite, a space station anda space detector.

The invention discloses an elastic-hinge-driven double-layer annular truss antenna mechanism, relates to an unfoldable antenna mechanism and aims to solve the problems that an existing monocyclic annular truss mechanism is decreased in rigidity along with increase of the antenna aperture and thereby cannot achieve the use stiffness requirements, and an existing annular truss antenna is complex in driving mechanism, large in mechanism weight and quite low in unfolding reliability. The elastic-hinge-driven double-layer annular truss antenna mechanism comprises inner-ring annular truss components, outer-ring annular truss components, a plurality of inner-and-outer-ring connection truss components and a plurality of inhaul cable components, each of the inner-ring annular truss components and the outer-ring annular truss components comprises a plurality of elastic-hinge-driven foldable and unfoldable units and a plurality of elastic-hinge-driven transition foldable and unfoldable components, each two adjacent elastic-hinge-driven foldable and unfoldable units are connected through the corresponding elastic-hinge-driven transition foldable and unfoldable component, and four corresponding vertex angles between each inner-ring annular truss component and the corresponding outer-ring annular truss component are supported and are connected rotatably by one inner-and-outer-ring connection truss component. The elastic-hinge-driven double-layer annular truss antenna mechanism is used for satellites, space stations and space probes.

The present invention provides a complete scissor-like double-layer annular truss extendible antenna mechanism. The mechanism comprises an inner layer annular truss component, an outer layer annular truss component and N inner and outer layer connection truss components; the inner layer annular truss component and the outer layer annular truss component both include N extending units; two common flower discs are connected between adjacent extending units; the inner and outer layer connection truss components are concentrically arranged; two upper and lower flower discs at each side of the inner layer extending units are connected with the corresponding two upper and lower outer layer flower discs at each side of the outer side layer extending units respectively through one inner and outer layer connection truss component to form a double-layer annular truss; and the distance between the length of the rod pieces at the same position of the inner and outer layer extending units and a flower disc rotation secondary axis and a center line satisfies a special proportional relation, and the ratio of the inner layer and the outer layer is (1-sin(180 / N)) / (1+sin(180 / N)). The complete scissor-like double-layer annular truss extendible antenna mechanism is high in rigidity, simple in structure and high in reliability, and can be applicable to a communication satellite, a space station and a space probe.

The invention belongs to the technical field of aerospace equipment and equipment, and in particular relates to a large-scale cable rod truss type deployable antenna mechanism. It includes several cable-rod-truss-type expandable units, and the several expandable units are connected by connecting longitudinal rods to form a cable-rod-truss-type expandable antenna mechanism; the expandable unit includes a first expandable component and is arranged on The second expandable component between the first expandable component, the first expandable component and the second expandable component are tripod bodies, the first expandable component and the second expandable component The expandable unit is formed by connecting with the third torsion spring joint. The invention has good reliability, compact structure, good rigidity after being fully unfolded, meets the use requirements of large space antennas, and is suitable for satellite space folding mechanisms and the like.

The invention provides a torsional spring driven shear-hinge ring rib type deployable antenna mechanism, which comprises radial deployable units and circumferential deployable units, each radial deployable unit comprises an inner faceplate, a first shear-fork rod, a second shear-fork rod, a third shear-fork rod and an outer faceplate, and the radial deployable units are arranged on the outer side of the inner faceplate in a circumferential array manner; the radial deployable units are connected with the circumferential deployable units through the outer disc chucks, the circumferential deployable units are sequentially connected end to end through the outer disc chucks, each circumferential deployable unit comprises a folding rod and a torsional spring driving assembly, and the folding rods are connected through the torsional spring driving assemblies. By adjusting the number of the radial deployable units and the circumferential deployable units and the lengths of the scissor rods and the folding rods forming the units, the deployable antenna mechanism with any caliber is formed, and the deployable antenna mechanism has the advantages of being good in manufacturability, high in rigidity, large in folding ratio and the like; the problems that an existing deployable antenna is complex in mechanism, low in reliability, poor in rigidity and strength and the like are solved, and the antenna can be better applied to communication satellites, space stations and space detectors.

The invention provides a double-layer annular truss antenna mechanism based on passive drive and relates to double-layer annular truss type expandable antenna mechanisms. The problems that an existing large-caliber single-ring annular truss antenna is small in rigidity, the use rigidity requirement can not be met, an existing annular truss antenna mechanism is complex in drive structure and large in weight, inhaul cables are prone to be twisted after being used for unfolding the mechanism, and the unfolding reliability is low are solved. The double-layer annular truss antenna mechanism comprises multiple inner and outer truss foldable unit modules, multiple inner transition folding assemblies and multiple outer transition folding assemblies. Each inner and outer truss foldable unit module comprises an inner folding unit module, an outer folding unit module and two inner and outer connection truss assemblies. Inner supporting vertical rods and outer supporting vertical rods which are opposite are connected through the inner and outer connection truss assemblies. After the inner and outer truss foldable unit modules are unfolded, an inner and outer double-layer annular truss polyhedron is formed. The double-layer annular truss antenna mechanism is used for a satellite, a space station and a space probe.

The invention discloses an anchorage type counterforce frame testing device applicable to underground space structures, and relates to the technical field of structural tests. The anchorage type counterforce frame testing device comprises a poured concrete steel square tube upright column, a counterforce frame anchorage system, a tensioner and a stress gauge. The poured concrete steel square tubeupright column is fixedly embedded in a foundation, the tensioner is used for adjusting the tension degree of a draw bar of the anchorage system, and the stress gauge is used for monitoring stress ofthe draw bar. The anchorage type counterforce frame testing device has advantages that the stiffness level of counterforce frames can be greatly upgraded, the load application safety guarantee level can be reinforced, experimental spaces can be effectively saved, and the anchorage type counterforce frame testing device has an excellent application prospect for carrying out structural tests in limited experimental spaces on basement first floors.

The invention discloses a load projection and mapping method for importing press forming information to a finite element simulation model. The method includes the following steps that node force information of a sheet is positioned, projected and mapped to a die profile grid twice during press forming; load information on the die profile grid is transmitted to a model tetrahedron unit, and node action forces of the sheet are directly applied to a die so as to replace the action of the sheet on the die. The method achieves force transmission between the sheet and the die during press forming, has an important theoretical guiding significance and application value in vehicle press forming die structural analysis, belongs to the technical field of vehicles, solves the problem of how to quickly and accurately project and map the press forming information of the sheet to the finite element simulation model in the prior art, and achieves load projection and mapping between node action forces of different grid models.

The invention relates to a single-layer regular hexagonal cone-type expandable truss antenna structure driven by torsion springs, which includes 12 right-angled triangular units, N rectangular foldable units, N≥6 and N is a multiple of 6, adjacent right-angled The triangular units are connected by a shared slanting bar and two 120-degree double-sided hinges up and down, and the adjacent rectangular folding units are connected by a shared vertical bar and two 180-degree double-sided hinges up and down. The two triangular units are connected to N / 6 rectangular The unit forms one side of the isosceles ladder shape of the truss antenna structure, and the six sides are connected by the oblique rod shared by adjacent triangular units and the upper and lower 120-degree double-sided hinges to form a regular hexagonal cone-type expandable truss antenna structure; after the present invention is folded Small in size and light in weight, the rods in the rectangular folding unit can be completely fitted after being folded, and the storage ratio is not less than 5%, which can meet the high storage ratio requirements of the large-diameter expandable antenna structure in space.