348results about "Elastic dampers" patented technology

The invention relates to a concave angle asymmetric double-layer negative Poisson's ratio superstructure and application thereof. A concave angle asymmetric double-layer negative Poisson's ratio superstructure comprises bearing pressing plates symmetrically arranged at the upper end and the lower end and a plurality of unit cell elements arranged between the two pressing plates, and is characterized in that the unit cell elements are arranged at equal intervals in the transverse direction and the vertical direction respectively to form an m * n array, each unit cell unit comprises a double-layer concave corner body, transverse connecting rods on the two sides and a vertical connecting rod on the upper portion, the lower portion of each double-layer concave corner body is an outer flat plate cell wall, and the ends of the transverse connecting rods between every two transversely adjacent unit cell units are connected into a whole. And the end parts of the vertical connecting rods between the vertically adjacent unit cell elements are connected with the outer flat plate cell walls into a whole. The deformation mode of the superstructure is influenced by the impact speed, when the speed is increased, the deformation mode transits from overall deformation to local deformation, different local deformation zones are generated, the superstructure has different horizontal contraction processes at different impact speeds, the negative Poisson's ratio effect is reduced along with the increase of the speed, and the local deformation zones are reduced. The superstructure can be applied to anti-impact protection parts of automobiles, airplanes and unmanned aerial vehicles and anti-impact protection parts of wearable protection devices.

The invention provides a negative poisson ratio tension metamaterial structure and application thereof in impact resistance of an unmanned aerial vehicle. The negative Poisson's ratio stretch-draw metamaterial structure is composed of a plurality of two-dimensional D-bar stretch-draw integral structures. The two-dimensional D-bar stretch-draw integral structure is composed of a plurality of two-dimensional D-bar stretch-draw unit structures. The two-dimensional D-bar tensioning unit structure is composed of four same rod pieces, four rigid hinges and two same elastic ropes. Wherein every two of four rod pieces of the two-dimensional D-bar tensioning unit structure are connected through a rigid hinge to form a quadrilateral structure, and the four rigid hinges are diagonally connected and fixed through two elastic ropes; and two elastic ropes are adopted for fixing. Compared with other stretch-draw metamaterial structures, the stretch-draw metamaterial based on the two-dimensional D-bar has the advantages that the negative Poisson's ratio structure can be utilized to show better energy absorption characteristics, and when the unmanned aerial vehicle collides or falls off, impact force can be effectively dispersed, and damage to an aircraft body is reduced.

The invention belongs to the technical field of vibration isolation, and particularly relates to a quasi-zero stiffness metamaterial sandwich structure, a vibration isolation device and a manufacturing method. The quasi-zero stiffness metamaterial sandwich structure is formed by periodically arranging unit cells in the horizontal direction, and each unit cell comprises an upper panel, a lower panel, a QZS resonator core body and a vertical supporting column; the QZS resonator core comprises a central mass block, QZS resonator units are arranged on the upper portion and the lower portion of the central mass block in a mirroring mode, each QZS resonator unit is composed of two quasi-zero-stiffness unit cells which are arranged in a crossed mode, and each quasi-zero-stiffness unit cell is composed of a negative-stiffness component comprising a horizontal curved beam and a positive-stiffness component comprising an oblique straight beam. According to the sandwich structure, the quasi-zero-stiffness resonator of a novel structure serves as a core body, wider application in the ultra-low frequency vibration reduction field can be achieved, the band gap is adjustable, and the problems that a traditional metal base material structure is high in band gap frequency and limited in application field can be solved.

An additively manufactured lattice includes a plurality of symmetrically oriented repeating unit cells. Each of the unit cells is comprised of a vertically oriented tubular structure having a top edge and bottom edge, said tubular structure defined by a circumferential side wall extending from said top edge to said bottom edge. The side wall has a lower portion, an intermediate portion, and an upper portion, with the lower portion terminating at the bottom edge, the upper portion terminating at the top edge, and the intermediate portion positioned between the lower portion and the upper portion. A plurality of spaced legs is included with each unit cell, with each leg formed as an outfolding of the side wall, each outfolding beginning at the side wall intermediate portion and extending progressively further outward through the side wall lower portion to the bottom edge.

The subject of the invention is an impact energy absorbing device, comprising a shock absorber (3) with a cylinder (3a) and piston rod (3b), a sleeve (1) to be cut and a machining tool (2) surrounding the sleeve (1) to be cut, for machining the surface of the sleeve (1) to be cut, characterized in that the sleeve (1) to be cut is a cylinder (3 a) of the shock absorber (3).

The application belongs to the technical field of deep-sea lander, and discloses a design method and system of a deep-sea landing buffer based on a filled TPMS structure, which comprises the following steps: S1, designing and preparing a filled TPMS structure; S2, performing a quasi-static compression test on the filled TPMS structure; S3, performing a dynamic impact performance test on the filled TPMS structure; S4, selecting a filled TPMS structure meeting preset requirements based on the results of the quasi-static compression test and the dynamic impact performance test, and designing a buffer system of a deep-sea lander; and S5, optimizing the buffer system of the deep-sea lander according to different application scenarios and equipment requirements. The application further explores the possibility of filling a magnetic fluid into a TPMS structure and applies the novel filled TPMS structure to a deep-sea landing buffer, thereby providing an efficient buffer solution for deep-sea exploration equipment.

The invention discloses a mechanical metamaterial cell element with a zero Poisson's ratio property, and belongs to the technical field of mechanical metamaterials. The upper top plate and the lower bottom plate are symmetrically arranged, the upper cleat nail set and the lower cleat nail set are arranged at the four corners of the inner side faces of the upper top plate and the lower bottom plate, the elastic body set is connected through the upper cleat nail set and the lower cleat nail set, and the flexible hinge component set is arranged at the midpoint position of four side lines of the upper top plate and the lower bottom plate. The flexible hinge component set keeps inward pre-bending through the pre-tension of the elastomer set, and when the cell element bears an axial load, the flexible hinge component set generates coordinated inward bending deformation, so that the cell element shrinks in the axial direction, the transverse size is kept stable, the axial zero Poisson's ratio characteristic is achieved, and meanwhile the energy absorption capacity is achieved. The cell element is based on elastic deformation, has self-recovery capability and long cycle life, adopts modular design, is convenient to assemble, disassemble and maintain, and is suitable for application scenes of aerospace buffer devices, biomedical implants, precise instrument supporting structures and the like.

The invention relates to an improved impact-resistant energy-absorbing structure of a trumpet-shell-imitating circular tube, and belongs to the technical field of impact-resistant protection, and a structural monomer or a structural modular array can be used for dynamic load protection. The structure of the circular tube is improved through a bionic method, on the premise that the mass of a traditional circular tube is not increased at all, the manufacturing cost is controllable by means of simple structural design, compared with the traditional circular tube, the energy absorption value under the unit mass is improved, and the problem of sharp initial peak crushing force existing in axial crushing of the traditional circular tube is thoroughly solved.

The negative poisson ratio energy absorption device comprises a honeycomb structure formed by a plurality of unit cell structure arrays, and each unit cell structure is formed by combining a plurality of plane energy absorption units around the same central axis in a radial shape in a crossed mode. Each plane energy absorption unit comprises an inwards-concave negative Poisson's ratio structure, two bionic treetop structures symmetrically arranged on the upper side and the lower side of the inwards-concave negative Poisson's ratio structure in the axial direction, and two connecting rods horizontally extending from the left side and the right side of the inwards-concave negative Poisson's ratio structure to the outer side. The bionic treetop structure comprises an arc-shaped top and a plurality of supporting rods distributed in a fan shape, one end of each supporting rod is connected to the arc-shaped top, and the other end of each supporting rod is connected to the concave negative Poisson's ratio structure; the device has the advantages that the device can adapt to multi-angle impact, and efficient and uniform energy absorption and light-weight protection are achieved through the negative Poisson's ratio effect.

The invention discloses a zero-Poisson-ratio composite material honeycomb core and a preparation method thereof, and belongs to the field of composite material forming. The honeycomb core comprises multiple layers of rib plates and multiple layers of stretching curved wall honeycombs, the rib plates are bonded between every two adjacent layers of stretching curved wall honeycombs and on the outer side of the stretching curved wall honeycomb on the outermost layer, and the multiple stretching curved wall honeycombs of each layer of stretching curved wall honeycombs are arranged in a matrix mode. A unit-cell concave hexagonal curved-wall honeycomb is formed between two adjacent stretching curved-wall honeycombs and rib plates, so that the zero Poisson ratio of the whole honeycomb structure is realized. The method comprises the following steps: designing the shapes of the prepreg and the demolding cloth; positioning the prepreg and the demolding cloth by using a positioning tool, and stacking the prepreg and the demolding cloth according to a specified sequence; for the thermosetting or thermoplastic fiber reinforced prepreg, a composite laminated plate is cured in a gradient manner by adopting a hot pressing process or a composite laminated plate is cured by adopting a mold pressing process; and finally, cutting, stretching, secondary curing, cooling and demolding cloth removal are carried out. The method is used for preparing the zero-Poisson-ratio composite material honeycomb core.

The invention relates to the technical field of bridge pile foundation construction, in particular to a bridge pile foundation construction vibration buffering device which comprises a support. The top end of the support is fixedly connected with a motor, the output end of the motor is fixedly connected with a lead screw, the lead screw is rotationally connected with the support, guide rods are arranged on the two sides of the lead screw and fixedly connected with the support, the outer side of the lead screw is in threaded connection with a lifting plate, and the two sides of the lifting plate are movably connected with the two guide rods in a sleeved mode respectively. Driving equipment is connected to the upper end of the lifting plate through a supporting assembly, a drill rod is fixedly connected to the bottom end of the driving equipment and penetrates through the supporting assembly and the lifting plate, and a clamping assembly is arranged on the outer side of the drill rod; the supporting assembly comprises a honeycomb plate, the honeycomb plate is composed of a plurality of honeycomb units, and the supporting assembly has the beneficial effects that by arranging multiple damping and buffering structures, it is prevented that driving equipment generates strong vibration in the running process, and consequently the driving equipment and a drill rod are greatly influenced, the stability of the drill rod in the drilling process is guaranteed, and therefore the construction quality is guaranteed.

The invention discloses a self-adaptive multi-stage negative Poisson's ratio energy absorption device and a manufacturing method.The self-adaptive multi-stage negative Poisson's ratio energy absorption device comprises a shell and a negative Poisson's ratio honeycomb structure arranged in the shell, and the negative Poisson's ratio honeycomb structure is formed by a plurality of self-adaptive negative Poisson's ratio unit cell arrays; each self-adaptive negative Poisson's ratio unit cell comprises a negative Poisson's ratio framework, an upper supporting structure and a lower supporting structure, the upper supporting structure and the lower supporting structure are connected to the interior of the negative Poisson's ratio framework, a horizontal supporting platform is arranged in the middle of the negative Poisson's ratio framework, and a preset gap allowing the negative Poisson's ratio framework to shrink and deform is formed in the middle of the horizontal supporting platform of the negative Poisson's ratio framework; the upper supporting structure extends downwards from the joint with the negative Poisson's ratio framework and is provided with an upper supporting platform, and the lower supporting structure extends upwards from the joint with the negative Poisson's ratio framework and is provided with a lower supporting platform; the self-adaptive graded protection device has the advantages that elastic buffering reusability of low-speed collision and multi-stage efficient energy absorption of high-speed collision can be both considered, and self-adaptive graded protection is achieved.

This invention relates to the field of novel materials, specifically a novel metamaterial exhibiting both multi-stable state and negative Poisson's ratio properties. It comprises a concave hexagonal frame, two arc-shaped beams positioned on the upper and lower sides of the frame's inner cavity, and a vertical rod. The two arc-shaped beams are fixedly connected to the upper and lower ends of the vertical rod via their respective central portions. When the structure is subjected to a vertical compressive load, the frame's diagonal bracing rotates inward, contracting and compressing the ends of the arc-shaped beams, generating a significant negative Poisson's ratio effect. This process forces the arc-shaped beams to bend and deform towards the center, accompanied by energy dissipation. When the displacement reaches a critical threshold, the arc-shaped beams buckle and overturn, switching to a steady state. This invention, through specific geometric configurations and differentiated material layouts, achieves morphological self-repair after impact and reuse under low-intensity conditions. This metamaterial can be arranged as a two-dimensional periodic array as a unit cell.

This impact absorption structure for a vehicle body is provided with an energy absorption member (20) having a cap-shaped cross-sectional shape in the direction in which a collision load is input. The cap-shaped top plate portion (20A) is disposed so as to face the input direction. The joint parts (20D, 20E) of the flange parts (20C) and the top plate part (20A) with respect to the pair of vertical wall parts (20B) are formed in a curved shape. The first dimension (L1) of the curved shape on the flange section (20C) side is equal to or greater than a predetermined value and equal to or greater than the second dimension (L2) of the curved shape on the top plate section (20A) side with respect to the dimensions in the direction in which the flange sections (20C) of the curved shape extend.

The invention discloses a vibration and noise reduction transmission system and rotary excavating power equipment, and relates to the technical field of power transmission, the vibration and noise reduction transmission system comprises a driving device, a driven device and a transmission device, the transmission device is in contact connection with the driving device and the driven device, and the transmission device comprises a pressurizing part and a vibration reduction part; the pressurizing part is a hard part and is used for power transmission, the vibration reduction part is an elastic energy absorption part and is used for generating elastic deformation when the pressurizing part transmits power, and the vibration transmission frequencies of different positions of the vibration reduction part are different. Buffering of collision is achieved through elastic deformation, noise attenuation is achieved from the interior of a sound source, the noise reduction efficiency is improved, vibration energy is transmitted through an elastic structure, fatigue damage to parts is avoided, the force transmission performance and the noise reduction requirement can be considered, the vibration transmission frequencies of different positions of the vibration reduction part are different, the fixed frequency is eliminated and stabilized, and mechanical waves are isolated.

To provide a shock absorber for a vehicle capable of suitably protecting a collision body from shock when the collision body collides with an exterior member, and capable of restraining reduction in cooling efficiency of a power device, even when arranged above a flow passage for making outside air flow to a power room from an outside air intake port.SOLUTION: The impact absorbing body 1 is positioned between the exterior member 103 and the power chamber PR in the longitudinal direction of the vehicle body 101, and is arranged above a flow passage 120 for circulating outside air from an outside air intake port 106a of the exterior member 103 to the power chamber PR. The shock absorber 1 includes a first portion 10, a second portion 20, and a shock absorbing portion 30 connecting the first portion 10 and the second portion 20. A plurality of through-holes 31a or the like penetrating in the vertical direction are formed in the shock absorbing part 30, and an inflow restraining body 40 extending in the longitudinal direction and extending in the vehicle cross direction, and restraining the hot air from the power chamber PR from flowing in between the first part 10 and the second part 20, is arranged above the shock absorbing part 30.SELECTED DRAWING: Figure 5

The invention relates to the technical field of damping structures, and discloses a shape memory polymer filled multistable negative Poisson's ratio structure damper which comprises a plurality of multistable structure shells which are of a bilateral symmetry structure and made of negative Poisson's ratio materials, cavities are defined in the multistable structure shells, and the multistable structure shells are arranged in an array mode; the shape memory polymer is arranged in the cavity, and the shape memory polymer is made of a shape memory negative Poisson's ratio polymer. The cavity is formed in the multi-stable-state structure shell, the cavity is filled with the shape memory polymer made of the shape memory negative Poisson's ratio polymer, the overall strength and rigidity of the structure can be improved while the negative Poisson's ratio characteristic is kept, and therefore the application range of the negative Poisson's ratio material in the vibration reduction field is expanded. The addition of the shape memory polymer is beneficial to improving the deformation capacity of the whole structure during bearing, and meanwhile, the structure can be recovered to the initial shape after being unloaded based on the recovery capacity of the shape memory polymer.

Deformation element for occupant protection in a motor vehicle, comprising a pot-shaped hollow profile section (17, 19) with a side wall (21) arranged at least partially rotationally symmetrically about the pot axis (A), a pot bottom side (23) facing away from the crash, and a top side (25) facing the crash, wherein the side wall (21) of the pot-shaped hollow profile section (17, 19) has at least one helical structure (27, 28, 29), characterized in that the helical structure (27, 28, 29) formed in the side wall (21) is truss-like with struts (31) and intermediate openings (33), and that the struts (31) are tilted with respect to the pot axis (A) by an angle of attack (α1, α2, α3), such that the pot-shaped hollow profile section (17, 19) deforms upon application of a force (F) in the direction the pot axis (A) under a torsional movement (II) a , II b , II c ) the side wall (21) is deformed.

The invention belongs to the technical field of impact protection and energy absorption, and particularly relates to a double-platform energy-absorbing buffer material with a negative Poisson's ratio characteristic, which comprises a top layer, an energy-absorbing layer group and a bottom layer which are fixedly arranged in sequence, the energy absorption layer set is composed of a plurality of stacked energy absorption layers, and each energy absorption layer comprises a plurality of energy absorption units arranged in a rectangular array. Each energy absorption unit comprises two orthogonally-arranged energy absorption unit cell structures, each energy absorption unit cell structure forms a first energy absorption cavity through a connecting face and a first inwards-concave structure, and a transverse rod and a second inwards-concave structure are arranged on the outer side of each first inwards-concave structure to form a second energy absorption cavity. The adjacent energy absorption units in the layers are connected through transverse rods, and the energy absorption layers are fixed through connecting faces. By means of various step-by-step buckling deformations of the two-stage concave structure, the first stress platform and the second stress platform which are independently adjustable are sequentially generated in the compression process, and efficient two-stage energy absorption is achieved; the three-dimensional structure has the negative Poisson's ratio effect and multidirectional bearing capacity, and can effectively avoid transverse expansion due to compression.

To provide an impact absorption member which can preferably absorb an impact itself while having rigidity to push out an occupant to a vehicle cabin inner side at an initial stage during a vehicle collision.SOLUTION: An impact absorption member includes: a first facing wall part 31 which is disposed facing a door trim 20; an inner wall part 32 extending from a peripheral end part of the first facing wall part 31 to a vehicle cabin outer side; a second facing wall part 33 which extends from a vehicle cabin outer end in the inner wall part 32 to an outer periphery direction side of the first facing wall part 31 and is disposed facing a door panel 10; an outer wall part 34 which extends from a peripheral end part of the second facing wall part 33 to a vehicle cabin inner side and encloses the inner wall part 32; and attachment parts 40, 50, 60 attached to the door trim 20.SELECTED DRAWING: Figure 2

The invention discloses a mining energy absorption box type anti-collision beam, and relates to a mine safety protection technology. The anti-collision beam comprises an anti-collision beam body fixed to the well wall, and a two-stage energy absorption structure is arranged on the collision side of the anti-collision beam body. The first-stage structure consists of first anti-collision square tubes which are parallel to the anti-collision beam and are welded with first energy absorption boxes; the second-stage structure is composed of a second anti-collision square pipe which is perpendicular to the anti-collision beam, connected with the beam body through bolts and welded with a second energy absorption box. The two-stage structure sequentially acts, and impact energy is absorbed in a graded mode through controllable plastic deformation of the energy absorption box. Traditional anti-collision wood is replaced with the energy absorption box combined structure, the problems that a traditional scheme is low in energy absorption efficiency, poor in impact resistance and high in maintenance cost are solved, the energy absorption box combined structure has the advantages of being efficient in energy absorption, stable in buffering, good in load dispersity and convenient to maintain, and the over-winding collision protection capacity of a coal mine hoisting system is remarkably improved.

The application discloses a metal honeycomb structure-based ring damper, which comprises a buffer module and a metal plate, wherein the buffer module is ring-shaped and comprises a honeycomb structure arranged along the central axis direction of the ring damper, and the density of the honeycomb structure is determined according to the low-pass filtering threshold and the crushing space required by the ring damper; the metal plate is arranged at both ends of the buffer module and covers the end faces of the honeycomb structure. The ring structure can reduce local stress and optimize the stress uniformity of the system, and the honeycomb structure can reduce the overall mass of the damper on one hand and can only be deformed to generate an effect when the impact energy threshold is above a specified value on the other hand, so that the initial kinetic energy is greatly reserved, and the overall system efficiency is improved.

To provide an impact energy absorption structure member having excellent impact energy absorption performance relative to an oblique impact.SOLUTION: An impact energy absorption structure member includes an aluminum extrusion material and has a shape in which an extrusion material cross section with a specific shape extends in an extrusion direction that is a vertical direction to the extrusion material cross section. The extrusion material cross section includes a shape in which two or more sections surrounded by a wall part comprising the aluminum extrusion material are aligned adjacent to each other in one direction. In an impact test, before a section 1 that receives an impact first is crushed completely, a boundary of a section 2 that receives the impact secondarily with the section 1 is deformed in an inner direction of the section 2, and a wall part that does not come into contact with a section other than the section 2 is deformed in an outer direction of the section 2 on the extrusion material cross section.SELECTED DRAWING: Figure 1

To provide a base isolation structure of a concrete column, which can enhance aseismatic strength without the need for large-scale construction work.SOLUTION: A concrete column for supporting an overhead electric wire, the concrete column being erected in a vertical direction, the concrete column being divided into an upper column part and a lower column part at a predetermined interval in a state where axes of the upper column part and the lower column part coincide with each other, A pair of flanged half-split steel pipes are joined to the lower end of the upper pillar part and the upper end of the lower pillar part so that the flanges face each other, a seismic isolation rubber body having a smaller outer shape than the flanges in a plan view is disposed between the upper pillar part and the lower pillar part, and a plurality of support members are disposed between the flanges of the pair of flanged half-split steel pipes so as to surround the seismic isolation rubber body.SELECTED DRAWING: Figure 1

The invention relates to the technical field of shock absorption supporting of aircrafts, and discloses a low-frequency shock absorption supporting structure and an aircraft, and the supporting structure is a metamaterial which is formed by arranging a plurality of cell element structures with the same structure in a planar array mode to form one or more layers of coupled and stacked metamaterials; the cell structure is a cylindrical structure enclosed by four wall plates, and a cavity is formed in the cell structure; each wall plate comprises a first plate section and second plate sections located on the upper side and the lower side of the first plate section. The first plate section is rectangular, and the second plate section is isosceles trapezoid; the first plate section is provided with two first edges which are opposite up and down; the second plate section is provided with a second edge parallel to the first edge, and the second edge is shorter than the first edge; the first plate sections of the adjacent cell structures are attached to each other, and the openings of the upper and lower cell structures are aligned during stacking. Through relative compression deformation motion between the top substrate and the cell element structure, vibration energy is absorbed, and the influence of vibration on precise instruments in the aircraft is reduced.

This invention discloses a buffer structure with negative stiffness and negative Poisson bit characteristics, which is composed of single-cell units arranged in a two-dimensional array. Each single-cell unit includes a first connecting beam, a second connecting beam, a crossbeam, a first side beam, a second side beam, and a bottom beam. The bottom beam is V-shaped, with one end fixed to one end of the first side beam and the other end fixed to one end of the second side beam. The other end of the first side beam is also fixed to the other end of the second side beam. The bottom beam is positioned between the first and second side beams, with one end fixed to the first side beam and the other end fixed to the second side beam, forming an isosceles triangle S with the first and second side beams. The lengths of the first and second connecting beams are half the length of the bottom beam, symmetrically positioned on both sides of the isosceles triangle S, with one end of the first connecting beam fixed to the first side beam and one end of the second connecting beam fixed to the second side beam. This invention exhibits two-stage compression characteristics, and its energy absorption performance is far superior to that of a single-configuration structure.

The invention belongs to the technical field of anti-impact protection. According to the snail shell imitating square tube improved anti-impact energy absorption structure and the application, the structural monomers or the structural modular array can be used for dynamic load protection. Under the action of an axial compression load, the structure realizes a multi-layer and progressive collapse path, and has low initial peak crushing force and staged and approximately linear increasing force-displacement response characteristics. According to the bionic structure, the energy absorption efficiency of the rectangular pipe is effectively improved under the condition that the mass and the manufacturing complexity are not increased, and the bionic structure is suitable for vehicle anti-collision systems, rail transit buffer devices and other anti-impact protection fields.

To provide a base-isolated structure capable of improving earthquake resistance of an upper structure at the time of excessive earthquake input.SOLUTION: A base isolation structure 100 including a base isolation layer 20, and an upper layer structure 22 placed above the base isolation layer 20 includes: a laminated rubber 24 which is provided on the base isolation layer 20, and has such hardening property as to reduce displacement of the base isolation layer 20; an elasto-plastic damper 26 and an oil damper 28 provided on the base isolation layer 20; and an oil damper 30 which is provided on the undermost layer of the upper structure 22, and suppresses vibration of the upper structure 22.SELECTED DRAWING: Figure 1

A seismic anchor, system, and structure are disclosed, the seismic anchor including a main member for attachment to a structure to be stabilized, a secondary member, and an anchor. The main member has a first tensile strength. The secondary member is attached to the main member, and has a second tensile strength lower than the first tensile strength. The anchor includes an anchor body attached to the secondary member and a moveable stop member attached to the main member, which is allowed to move relative to the anchor body such that in a first mode, force is applied to the anchor body through the secondary member, and in a second mode in which the secondary member has yielded, force is applied to the anchor body through the main member and the moveable stop member.