CN112525732B - Mechanical application method and device for vertically and uniformly distributing explosive load - Google Patents
Mechanical application method and device for vertically and uniformly distributing explosive load Download PDFInfo
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Abstract
The invention belongs to the technical field of explosion tests, and particularly provides a mechanical application method and a device for vertically and uniformly distributing explosion loads.
Description
Technical Field
The invention belongs to the technical field of explosion tests, and particularly relates to a mechanical application method and device for vertically and uniformly distributing explosion loads.
Background
Explosion test is an important research means in the fields of damage assessment and protection engineering, and at present, a model or prototype test is mainly carried out in a mode of explosive explosion. The outdoor chemical explosion test can accurately simulate the real situation, obtain the real explosion damage state and test the actual effect of the protection technical means. However, the field chemical explosion test has the problems of complex explosive approval procedure, long test preparation time, high test cost, high measurement technical difficulty, poor test data repeatability and the like, and is mostly suitable for testability tests. In an indoor modeled explosion test, the repeatability of test data is good, but the problems of complex explosive examination and approval procedures, long test preparation time and the like still exist.
In order to improve the flexibility and convenience of the test, a test technology for simulating the explosive impact load by falling weight impact appears. The test component impacts on large-scale drop hammer equipment, and can simulate the effect of explosive impact load to a certain extent. The method for applying the similar explosion impact load in a mechanical mode is safe and convenient compared with an explosion test, and the test repeatability is good. However, most of the existing domestic large-scale drop hammer equipment generates local explosion impact loads, and the requirement of researching the structural influence under the action of uniformly distributed explosion impact loads is difficult to meet.
Disclosure of Invention
Aiming at the problems in the prior art, the invention aims to provide a mechanical application method and device for vertically and uniformly distributing an explosion load. The mechanical applying device for the vertically and uniformly distributed explosive load provided by the invention has the advantages that the falling body vertically falls on the top surface of a sand layer during the test, the load is further transmitted to the structural model, the detection device can detect the pressure and the strain generated by the structural model, and the relation between the load and the structural response is further obtained. The invention applies vertically and uniformly distributed explosive load by using a mechanical mode, can meet the requirements of the test research of a shallow buried structure model in soil and the dynamic response test research of the component in the far explosion region, has simple structure, low cost and good repeatability, is particularly suitable for the principle experiment at the early stage of a project and finds the law of explosive dynamic load and structural response.
The technical scheme is as follows:
a mechanical application method for vertically and uniformly distributing explosive loads comprises the following steps:
the method comprises the following steps: determining a structural model;
step two: arranging protective layers above the structural model; the protective layer comprises a sand layer, a cover plate and a cushion layer with adjustable thickness;
step three: judging whether a lifting mechanism for testing is provided with a secondary impact prevention device, wherein the secondary impact prevention device locks a falling body after the bottom surface of the falling body is contacted with an object, and eliminates waveform interference caused by secondary impact of the falling body;
if the lifting mechanism for the test is not provided with the secondary impact prevention device, turning to the fourth step;
if the lifting mechanism for the test is provided with the secondary impact prevention device, directly switching to the fifth step;
step four: a buffer layer is arranged between the cover plate and the sand layer;
step five: arranging a pressure sensor on the outer side wall of the top surface of the structural model, wherein the side wall and the top of the pressure sensor are both in contact with sand;
step six: disposing a plurality of strain gauges to an inner surface of a top surface of the structural model;
step seven: determining the mass m of the falling body, wherein the area of the bottom surface of the falling body is larger than that of the top surface of the sandy soil layer, so that the falling body can be ensured to apply vertically and uniformly distributed load to the structural model when falling;
step eight: determination of the peak value sigma of a stress wave in the soil max Setting the lifting height of the falling body;
wherein the expression of the lift height h is as follows,
wherein σ max Is the peak value of the stress wave in the soil, rho 1 c 1 Wave impedance of falling body material, p 2 c 2 Is the wave impedance of the cover material, p 3 c 3 Wave impedance of sand, p 1 As falling body material density, c 1 Is the wave velocity, p, of the falling body material 2 Is the density of the cover material, c 2 Is the wave velocity, p, of the cover material 3 Is the density of sandy soil material, c 3 The wave velocity of the sandy soil material is adopted, and g is the gravity acceleration;
step nine: setting the thickness of the cushion layer to be H, lifting the falling body to a preset position according to the lifting height obtained in the step eight, and impacting a structural model by using the falling body;
step ten: connecting the pressure sensor and the strain gauge to a broadband strain gauge and a transient recorder to obtain a pressure oscillogram and a strain oscillogram of a structural model;
step eleven: comparing the waveform obtained by the pressure sensor with a preset waveform, and judging the relation between the pressure waveform obtained in the step ten and the preset waveform; the dynamic response of the main structure is ensured to be within a preset range through the strain waveform, and the structure is prevented from being damaged;
if the pressure waveform in the step ten is not matched with the preset waveform, turning to the step twelve;
if the pressure waveform in the step ten is matched with the preset waveform, turning to a step thirteen;
step twelve: changing the thickness of the cushion layer above the cover plate and/or the lifting height of the falling body, and turning to the ninth step;
when the measured pressure waveform peak value is smaller than the preset waveform peak value, the height of the falling body is lifted;
when the measured pressure waveform pulse width is smaller than the preset waveform pulse width, increasing the thickness of the cushion layer;
step thirteen: and completing pressure waveform debugging, and performing a soil shallow buried structure model test or an explosion remote zone component dynamic response test.
Preferably, the step of determining the elevation height is as follows,
s1: after the falling body impacts the cover plate, calculating the stress sigma generated by the falling body on the contact surface of the falling body and the cover plate j ；
The stress sigma generated on the contact surface of the cover plate is obtained according to the condition of discontinuous wave jump in the solid j ，
σ j ＝ρ 1 c 1 (V 1 -V)
σ j ＝-ρ 2 c 2 V 1
Where ρ is 1 c 1 Wave impedance of falling body material, p 2 c 2 Is the wave impedance of the cover material, p 1 As falling body material density, c 1 Is the wave velocity, p, of the falling body material 2 Is the density of the cover material, c 2 Is the wave velocity of the cover sheet material; v is the speed of impact of the falling body on the concrete cover plate, V 1 Stress sigma produced on contact surface of cover plate for medium common speed movement on contact surface j Is the stress of the top surface of the cover plate, σ j ＝-ρ 2 c 2 V 1 In, "-" represents a down-going wave;
the stress sigma generated on the contact surface of the cover plate can be obtained j Is composed of
Where ρ is 1 c 1 Wave impedance of falling body material, p 2 c 2 Is the wave impedance of the cover material; v is the speed of the falling body impacting the concrete cover plate; rho 1 As falling body material density, c 1 Is the wave velocity, p, of the falling body material 2 Is the density of the cover material, c 2 Is the wave velocity of the cover plate material;
s2: calculating the stress sigma generated on the contact surface of the cover plate j Stress transmitted to the sand layer;
one-dimensional elastic waves are transmitted to the sandy soil layer from the cover plate, wherein the wave impedance of the cover plate is rho 2 c 2 Sand layer with wave impedance rho 3 c 3 The propagation direction of the one-dimensional elastic wave is perpendicular to the interface, and the two media are always kept in contact with each other at the interface, so that the particle velocity and the stress of the two sides of the interface after the transmission and reflection of the stress wave are equal according to the continuous condition and Newton's third law,
V I +V R ＝V T
σ I +σ R ＝σ T
in the formula: v I Is the particle velocity, V, of the incident wave R Is the particle velocity, V, of the reflected wave T Is the particle velocity of the transmitted wave;
σ I is the particle stress, σ, of the incident wave R Is the particle stress, σ, of the reflected wave T Is the particle stress of the transmitted wave;
it is possible to obtain,
therefore, the temperature of the molten metal is controlled,
let σ be the attenuation of stress in the cover plate irrespective j ＝σ I Wherein the particle stress of the transmitted wave is the stress transmitted into the sandy soil layer, and the stress sigma transmitted into the sandy soil layer T Comprises the following steps:
where ρ is 1 c 1 Wave impedance of falling body material, p 2 c 2 Is the wave impedance of the cover material, p 3 c 3 The wave impedance of the sand is shown, and V is the speed of the falling body impacting the concrete cover plate; rho 1 Density of falling body material, c 1 Is the wave velocity, p, of the falling body material 2 Is the density of the cover material, c 2 Is the wave velocity, p, of the cover material 3 Is the density of sandy soil material, c 3 The wave velocity of the sandy soil material;
s3: determining the lifting height of the falling body;
let the drop with mass m fall with height h, the velocity when hitting the concrete cover plate 7 is V, according to the conservation of energy:
the following can be obtained:
the lifting height h of the falling body is: :
where ρ is 1 c 1 Wave impedance of falling body material, p 2 c 2 Is the wave impedance of the cover material, p 3 c 3 Wave impedance of sand, p 1 As falling body material density, c 1 Is the wave velocity, p, of the falling body material 2 Density of cover material, c 2 Is the wave velocity, p, of the cover material 3 Is the density of sandy soil material, c 3 The wave velocity of the sandy soil material is used, and g is the gravity acceleration; sigma T For transmission to sandStress in the earth layer with a peak value of σ max ，σ max The peak value of stress wave in the sandy soil is shown, and g is the gravity acceleration.
Preferably, in the above step six, the strain gauge is provided in the midspan of the inner surface of the top surface of the structural model; the mid-span is located at a midline of the top surface parallel to the two side portions, along which the strain gage is disposed.
Preferably, in the second step, a sand layer is arranged above the structural model, the sand layer is enclosed by the enclosing structure, a cover plate is arranged on the sand layer, and a cushion layer is arranged on the cover plate.
Preferably, in one of the steps, the structural model includes a top surface, a bottom surface, and side surfaces that form a support between the top and bottom surfaces; the number of the side surfaces is two, and the two side surfaces are oppositely arranged, so that an opening is formed in the box-type structure, and the strain gauge is convenient to mount.
In the ninth step, the falling body is lifted to a preset position by using a lifting mechanism, the preset position is the lifting height h +/-100 mm, then the falling body is released, the falling body is made to fall, and the vertical uniform explosive load is simulated by a mechanical mode.
Preferably, in the seventh step, the falling body mass is more than 200 kg.
In the fifth step, the sandy soil layer comprises a plurality of pressure sensors; at least one pressure sensor is positioned on the outer side wall of the top surface of the structural model;
preferably, a pressure sensor is also provided on the outer side wall of the interior of the sand layer not proximate to the top surface of the structural model.
A mechanical applying device for vertically and uniformly distributing explosive loads comprises a main body structure, a lifting mechanism, an impact applying device, an envelope structure, a sand layer, a cushion layer, a cover plate, a pressure sensor and a strain gauge, wherein the impact applying device does falling motion to simulate impact, the main body structure is arranged on a working platform, and the impact simulating device is lifted by the lifting mechanism; an enclosure structure is arranged at the top of the main structure, and sandy soil is arranged in the enclosure structure to form a sandy soil layer; the cover plate is arranged at the top of the building enclosure, and a cushion layer is arranged at the upper part of the cover plate to change the peak value and the pulse width of impact; the strain gauge is arranged on the inner side wall of the top of the main body structure, the structural response of the main body structure is collected through the strain gauge, and the strain condition of the main body structure under the action of impact force is analyzed so as to measure the deformation resistance of the structure of the main body; the pressure sensor is arranged on the outer surface of the top of the main structure, the vertical and uniform distributed impact load is detected through the pressure sensor, the pressure sensor and the strain gauge are connected to the broadband strain gauge and the transient recorder, so that the waveform of the strain gauge is recorded, the obtained waveform is compared with the preset waveform until the waveform obtained by the test is matched with the preset waveform, and the follow-up test is continued.
Preferably, the strain gauge is disposed on a centerline of an inner sidewall of the top of the body structure.
Preferably, the lifting mechanism is a hydraulic lifting mechanism.
Preferably the sand layer is level with the upper edge of the enclosure.
Preferably, the cover plate is a concrete cover plate.
Preferably, the cushion layer is a rubber layer, when the impact simulator impacts downwards due to falling, the rubber layer can change the peak value and the pulse width of the impact, and the waveform and the pulse width are adjusted by adjusting the thickness of the rubber layer.
Preferably, the buffer layer is a porous structure layer capable of transferring the kinetic energy of the first falling impact.
Preferably, a pressure sensor may also be provided at the outer surface of the interior of the sand layer remote from the top of the host structure.
Preferably, the enclosure is a four-sided enclosure that is free of a bottom side and a top side, the sand directly contacting an outer surface of the top of the body structure.
According to the embodiment of the invention, the mechanical applying device for vertically and uniformly distributing the explosive load comprises a structural model, a sand layer, a detection device, a falling body and a lifting mechanism; the sand layer is positioned above the structural model; the detection device is arranged on the structural model and the sand layer; the lifting mechanism is positioned outside the structural model and the sandy soil layer; the falling body is installed on the lifting mechanism and is positioned above the sand layer.
The mechanical explosive load applying device for vertically and uniformly distributing explosive loads as described above is further preferably: the bottom surface of the falling body is a plane, and the area of the bottom surface is larger than that of the top surface of the sand layer.
The mechanical applying device for vertically and uniformly distributing the explosive load as described above is further preferably: the mass of the drop is adjustable.
The mechanical explosive load applying device for vertically and uniformly distributing explosive loads as described above is further preferably: the lifting mechanism is a hydraulic lifting mechanism and can have a secondary impact prevention function.
The mechanical explosive load applying device for vertically and uniformly distributing explosive loads as described above is further preferably: the structure model is a box structure.
The mechanical applying device for vertically and uniformly distributing the explosive load as described above is further preferably: the structural model is a reinforced concrete structure or a glass fiber reinforced plastic structure.
The mechanical explosive load applying device for vertically and uniformly distributing explosive loads as described above is further preferably: and an enclosure structure is arranged around the sandy soil layer and used for enclosing the sandy soil layer above the structural model.
The mechanical explosive load applying device for vertically and uniformly distributing explosive loads as described above is further preferably: the enclosure structure is a plate-shaped structure.
The mechanical explosive load applying device for vertically and uniformly distributing explosive loads as described above is further preferably: the detection device comprises a pressure sensor and a strain gauge; the pressure sensor is located in the sandy soil layer, and the strain gauge is located on the inner side of the top wall of the structural model.
The mechanical applying device for vertically and uniformly distributing the explosive load as described above is further preferably: the cover plate is characterized by further comprising a cushion layer, wherein the cushion layer is located above the cover plate, and preferably, the cushion layer can be a rubber material layer.
Analysis shows that compared with the prior art, the invention has the advantages and beneficial effects that:
the mechanical application method of the vertically uniformly distributed explosive load is configured for impact simulation of the vertically uniformly distributed explosive load, different structural models are manufactured according to different test requirements, protective layers are arranged on the structural models, and required waveforms are obtained by adjusting parameters of the protective layers and are used for simulation tests. The method applies vertically and uniformly distributed explosive loads in a mechanical mode, can meet the requirements of the test research of the shallow buried structure model in the soil and the dynamic response test research of the component in the far explosion region, is simple and easy to implement, low in cost and good in repeatability, is particularly suitable for the principle experiment in the early stage of a project, and finds the law of explosive dynamic load and structural response.
Drawings
Fig. 1 is a schematic structural view of a mechanical application device for vertically distributing explosive loads according to the present invention.
Fig. 2 is a sectional view of the structural model and the envelope of the mechanical explosive load applying device in fig. 1 for vertically and uniformly distributing explosive loads, wherein according to an embodiment of the invention, the upper surface of the sand layer may be flush with the upper surface of the envelope, the upper surface of the sand layer may be lower than the envelope, and the upper surface of the sand layer in fig. 2 is lower than the envelope.
Fig. 3 is a schematic view of the installation position of the strain gauge of the mechanical application device for vertically distributing explosive loads according to the embodiment of the present invention in fig. 2.
Fig. 4 is a pressure waveform diagram of a mechanical application device for vertically distributing an explosive load according to an embodiment of the present invention.
Fig. 5 is a strain waveform diagram of a mechanical application device for vertically distributing an explosive load in accordance with an embodiment of the present invention.
Fig. 6 is a flow chart of a method of mechanically applying a vertically uniform blast load in accordance with an embodiment of the present invention.
In the figure: 1-a lifting mechanism; 2-falling body; 3, building enclosure; 4-structural model; 5-a sandy soil layer; 6-cushion coat; 7-cover plate; 8-a buffer layer; 9-a pressure sensor; 10-strain gauge.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
In the description of the present invention, the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are for convenience of description of the present invention only and do not require that the present invention must be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. The terms "connected" and "connected" as used herein are intended to be broadly construed, and may include, for example, fixed connections and removable connections; they may be directly connected or indirectly connected through intermediate members, and specific meanings of the above terms will be understood by those skilled in the art as appropriate.
Referring to fig. 1 to 5, fig. 1 is a schematic structural view of a mechanical applying device for vertically and uniformly distributing an explosive load; FIG. 2 is a cross-sectional view of the structural model and the building envelope of FIG. 1; FIG. 3 is a schematic view of the mounting position of the strain gage of FIG. 2; FIG. 4 is a pressure waveform diagram; fig. 5 is a strain waveform diagram. Wherein, in fig. 4, the minus sign (-) represents downward; the curve of which the pressure reaches between-2.4 MPa and-2.8 MPa is a curve of P2 and is detected by a pressure sensor positioned in the middle of the sandy soil layer; the other curve is a curve P1, which is a curve detected by a pressure sensor on top of the model of the conformable structure. In fig. 5, the three curves are a curve corresponding to epsilon 1, a curve corresponding to epsilon 3 and a curve corresponding to epsilon 2 from top to bottom in sequence at a position close to the horizontal position; the curve corresponding to epsilon 1 is a curve obtained by detecting the middle strain gauge in the three strain gauges, and the curve corresponding to epsilon 3 and the curve corresponding to epsilon 2 are curves obtained by detecting the strain gauges on two sides.
The mechanical applying device for vertically and uniformly distributing the explosive load comprises a main body structure, a lifting mechanism, an impact applying device, a building envelope, a sand layer, a cushion layer, a cover plate, a pressure sensor and a strain gauge. The impact applying device does falling body movement to simulate impact, the main body structure is arranged on the working platform, and the impact simulating device is lifted by the lifting mechanism; the top of the main structure is provided with an enclosure structure, and sandy soil is arranged in the enclosure structure to form a sandy soil layer. The top of the enclosure structure is provided with the cover plate, and the upper part of the cover plate is provided with a cushion layer for changing the peak value and the pulse width of impact. The envelope is the surrounding structure of four sides, and it does not have bottom surface and top surface, the surface at the top of sand direct contact major structure. Preferably, the pressure sensor may be further provided at an outer side portion of the top of the body. The vertical and uniform distribution impact load is detected through a pressure sensor, the pressure sensor and the strain gauge are connected to a broadband strain gauge and a transient recorder so as to record the waveform of the strain gauge, the obtained waveform is compared with a preset waveform until the waveform obtained by the test is consistent with the preset waveform, and the subsequent test is continued.
The strain gauge is arranged on the inner side wall of the top of the main body structure; preferably, the strain gauge is disposed on a centerline of an inner sidewall of the top portion of the body structure.
And acquiring the structural response of the main body structure through the strain gauge, and analyzing the strain condition of the main body structure under the action of impact force so as to measure the deformation resistance of the structure of the main body.
Preferably, a pressure sensor may also be provided inside the sand layer, i.e. at the outer surface remote from the top of the body structure.
Preferably, the main structure may be a box structure, a plate or a beam, that is, the main structure is a test piece.
Preferably, the lifting mechanism is a hydraulic lifting mechanism.
Preferably, the envelope extends upwards along the edge of the top of the main body structure, and sandy soil is arranged in the envelope to form a sandy soil layer.
Preferably the sand layer is level with the upper edge of the enclosure.
Preferably, the cover plate is a concrete cover plate.
Preferably, the cushion layer is a rubber layer, and when the impact simulation device falls and impacts downwards, the rubber layer can change the peak value and the pulse width of the impact, namely the waveform and the pulse width are adjusted by adjusting the thickness of the rubber layer, so that the problem of single waveform generated by directly impacting the concrete cover plate after the impact simulation device falls is effectively solved. The invention meets the problems of test diversity and flexibility.
Preferably, the envelope is provided with the buffer layer with the top in sand layer, the buffer layer configuration is used for preventing to strike and leads to secondary collision when analogue means to the falling body, produces the clutter, influences the contrast effect between the wave form that the experiment obtained and the predetermined wave form. Preferably, the buffer layer is a porous structure layer capable of transferring the first impact pressure to the sand layer.
In parallel, the impact simulation device itself is provided with a secondary collision prevention device, and the buffer layer can be eliminated.
The body structure is configured in the following description to simulate a shallow underground body structure, which in the following description of specific examples is a box structure having a top surface, a bottom surface and two of its opposite side surfaces; in the following description, the impact simulation means is the falling body 2, and the detection means includes a pressure sensor and a strain gauge.
Specifically, as shown in fig. 1, 2 and 3, the mechanical application device for vertically and uniformly distributing explosive loads of the invention comprises a structural model 4, a sand layer 5, a detection device, a falling body 2 and a lifting mechanism 1. The sand layer 5 is located above the structural model 4 and completely covers the top surface of the structural model 4. The detection device is arranged on the structure model 4 and the sand layer 5; the lifting mechanism 1 is positioned outside the structural model 4 and the sandy soil layer 5; the falling body 2 is mounted on the hoisting mechanism 1 above the sand layer 5. The falling body 2 is lifted to the height required by each test through a lifting mechanism after falling, the lifting mechanism 1 comprises hydraulic equipment and four vertically arranged stand columns, and guide rails are arranged on the stand columns.
The guide rail can make reciprocating of falling body 2 more convenient, through hydraulic equipment lifting falling body 2 to required high back, will through stop device falling body 2 stops at required height, and falling body 2 is along guide rail 22 whereabouts impact structure model 4 when treating the test next time.
The falling body 2 vertically falls on the top surface of the sand layer 5 during the test of the mechanical applying device for vertically and uniformly distributing the explosive load, so that the load is transmitted to the structural model 4, and the detecting device can detect the pressure and the strain generated by the structural model 4, so as to obtain the relation between the load and the structural response. The invention applies vertically and uniformly distributed explosive load by using a mechanical mode, can meet the requirements of the test research of a shallow buried structure model in soil and the dynamic response test research of the component in the far explosion region, has simple structure, low cost and good repeatability, is particularly suitable for the principle experiment at the early stage of a project and finds the law of explosive dynamic load and structural response.
Further, in the invention, the bottom surface of the falling body 2 is a plane, and the area of the bottom surface is larger than the area of the top surface of the sand layer 5, namely the area of the bottom surface of the falling body 2 is larger than the area of the top surface of the structural model 4, so that the requirement of simulating the vertically and uniformly distributed explosive load applied to the structural model 4 can be met. Preferably, the mass of the drop 2 is adjustable to meet the requirements for performing tests of different parameters.
The lifting mechanism 1 is a hydraulic lifting mechanism and has a secondary impact prevention function, the falling body 2 is locked immediately after the bottom surface of the falling body 2 is contacted with an object, and waveform interference caused by secondary impact of the falling body 2 can be eliminated.
Further, in the invention, the enclosing structure 3 is arranged around the sandy soil layer 5, and the enclosing structure 3 can enclose the sandy soil layer 5 above the structure model 4. The material of the sandy soil layer 5 is consistent with the soil body expected to bear the explosive load, and when the thickness is selected, the thickness of the actual sandy soil is scaled proportionally according to the ratio between the structure model 4 and the actual structure.
Optionally, in the present invention, the building structure further includes a cover plate 7, the cover plate 7 is located above the sandy soil layer 5 and inside the envelope 3, a top surface of the cover plate 7 is higher than a top surface of the envelope 3, and when the falling body 2 falls, the falling body can be completely hammered onto the cover plate 7 without contacting with the envelope 3. According to the invention, the cover plate 7 is arranged, so that the load brought by the falling body 2 can be concentrated, and further the sand layer 5 can be loaded with the required concentrated and uniformly distributed load.
Further, in the present invention, the pressure regulator further includes a cushion layer 6, the cushion layer 6 is located on the top surface of the cover plate 7, the cushion layer 6 is made of an elastic material, preferably rubber, and the pressure waveform is further adjusted by adjusting the thickness of the cushion layer 6.
Alternatively, if the lifting mechanism of the present invention has no device for preventing secondary collision, the present invention further comprises a buffer layer 8, the buffer layer 8 is located between the bottom surface of the cover plate 7 and the sand layer 5, the buffer layer 8 is an elastic layer made of a foam material, for example, foamed polyurethane, foamed polyethylene, or foamed rubber, and has a plurality of holes, which can play a role of buffering, so as to eliminate the waveform interference caused by secondary collision after the falling body 2 is knocked down.
Further, in the present invention, the structural model 4 is any one of a reinforced concrete structure, a glass fiber reinforced plastic structure, and a steel structure; the enclosure structure 3 is a plate-shaped structure; the cover plate 7 is of any one of a steel structure and a reinforced concrete structure.
As shown in fig. 1 to 5, according to the above mechanical application device for vertically and uniformly distributing an explosive load, the present invention further provides a mechanical application method for vertically and uniformly distributing an explosive load, comprising the following steps:
the method comprises the following steps: determining a structural model;
preferably, the structural model is manufactured according to the structure of the to-be-tested piece to be tested.
Preferably, the structural model is a body structure, which may be a box structure, a plate or a beam. As mentioned above, the structure model of the subject, the structure model in step one, also needs to be changed accordingly. That is, the main structure is a test piece.
Preferably, the structural model according to an embodiment of the invention comprises a top surface, a bottom surface and side surfaces, the side surfaces forming a support between the top surface and the bottom surface. Still further in accordance with a preferred embodiment of the present invention the number of sides is two and the two sides are oppositely disposed to form an opening in the box structure to facilitate the mounting of the strain gage.
Step two: arranging protective layers above the structural model;
preferably, the protective layer comprises a sand layer, a cover plate and a cushion layer;
preferably, a sand layer is arranged above the structural model, the sand layer is surrounded by the envelope structure, a cover plate is arranged on the sand layer, a cushion layer is arranged on the cover plate, and the thickness of the cushion layer is determined;
preferably, the cover plate is a concrete cover plate.
Specifically, a structural model 4 is manufactured according to a structure which needs to be detected actually, a sandy soil layer 5 is placed on the top surface of the structural model 4, an envelope structure 3 is arranged on the outer side of the sandy soil layer, and the sandy soil layer 5 is enclosed above the structural model 4 by the envelope structure 3. The enclosure 3 is a rectangular frame with only side walls. Cover plate 7 is set up to sand layer 5 top, and cover plate 7 top surface is higher than envelope 3's top surface, and the cover plate forms sandy soil accommodation space with the maintenance structure, sets up buffer layer 8 between cover plate 7 and the sand layer 5, and it can the filtering clutter.
Step three: judging whether a lifting mechanism for testing is provided with a secondary impact prevention device, wherein the secondary impact prevention device locks a falling body after the bottom surface of the falling body is contacted with an object, and waveform interference caused by secondary impact of the falling body is eliminated;
if the lifting mechanism for the test is not provided with the secondary impact prevention device, turning to the fourth step;
if the lifting mechanism for the test is provided with the secondary impact prevention device, directly turning to the fifth step;
step four: a buffer layer 8 is arranged between the cover plate 7 and the sand layer 5;
preferably, the cushioning layer 8 is a porous layer supported by a foam material.
Step five: arranging a pressure sensor 9 on the outer side wall of the top surface of the structural model 4, wherein the side wall and the top of the pressure sensor 9 are both in contact with sand;
preferably, the sand layer includes a plurality of pressure sensors; further, the at least one pressure sensor 9 is located at an outer side wall of the top surface of the structural model 4, i.e. the at least one pressure sensor is located at an outer surface of the top surface of the structural model 4.
Preferably, a pressure sensor is also provided on the outer side wall of the interior of the sand layer not proximate to the top surface of the structural model.
Step six: below the top surface of the structural model 4, i.e., the inner surface of the top surface of the structural model, a plurality of strain gauges 10 are provided;
preferably, the strain gauge 10 is provided in the span of the inner surface of the top face of the structural model 4; that is, the mid-span is located at a centerline of the top surface parallel to the two side portions, along which the strain gages are disposed, e.g., uniformly spaced apart.
Step seven: determining the mass m of the falling body 2, wherein the area of the bottom surface of the falling body 2 is larger than that of the top surface of a sand layer;
that is, the area of the bottom surface of the falling body 2 is larger than the area of the top surface of the construction model 4, so that the falling body can surely apply a vertically uniform load to the construction model when falling.
Preferably, in order to facilitate the application of a load to the structural model 4, the falling body 2 is generally a steel material, and the mass is selected to be more than 200 kg.
Further, in order to apply a vertically uniform load to the structural model, the bottom surface of the falling body is provided as a plane.
Step eight: determining the peak value sigma of a stress wave in the soil max Setting the lifting height of the falling body 2;
wherein the expression of the lift height h is as follows,
wherein σ max Is the peak value of the stress wave in the sand, rho 1 c 1 Wave impedance, p, of the material of the falling body 2 2 c 2 Wave impedance, p, of the material of the cover plate 7 3 c 3 Wave impedance of sand, p 1 As falling body 2 material density, c 1 Wave velocity, p, of the material of the falling body 2 2 Is the density of the material of the cover plate 7, c 2 Wave velocity, p, of the material of the cover plate 7 3 Is the density of sandy soil material, c 3 The wave velocity of the sandy soil material is shown, and g is the gravity acceleration.
Preferably, the range of the lifting height of the falling body 2 during the test is further determined according to the lifting height of the falling body 2. Preferably, the lifting height fluctuates up and down around the estimated height, and the fluctuation range is +/-100 mm, so that the test process is safer.
Wherein the step of determining the lift height is as follows,
s1: after the falling body 2 impacts the cover plate 7, the stress sigma generated on the contact surface of the falling body 2 is calculated j ；
The stress sigma generated on the contact surface of the cover plate 7 is obtained according to the condition of discontinuous wave leap in the solid j ，
σ j ＝ρ 1 c 1 (V 1 -V) (2)
σ j ＝-ρ 2 c 2 V 1 (3)
Where ρ is 1 c 1 Wave impedance, p, of the material of the falling body 2 2 c 2 Wave impedance, p, of the material of the cover plate 7 1 As falling body 2 material density, c 1 Wave velocity, p, of the material of the falling body 2 2 Is the density of the material of the cover plate 7, c 2 Is the wave velocity of the material of the cover plate 7; v is the speed at which the falling body 2 hits the concrete cover plate 7, V 1 Stress sigma generated on the contact surface of the cover plate 7 for medium common velocity movement on the contact surface j Is the stress of the top surface of the cover plate 7, σ j ＝-ρ 2 c 2 V 1 In, "-" indicates a down-traveling wave.
Further, the stress σ generated on the contact surface of the cover plate j Is composed of
Where ρ is 1 c 1 Wave impedance, p, of the material of the falling body 2 2 c 2 Wave impedance, p, of the material of the cover plate 7 1 As falling body 2 material density, c 1 Wave velocity, p, of the material of the falling body 2 2 Is the density of the material of the cover plate 7, c 2 Is the wave velocity of the cover plate 7 material; v is the speed at which the drop 2 hits the concrete deck 7 and "-" indicates the stress direction downwards.
S2: calculating the stress sigma generated on the contact surface of the cover plate 7 j The stress transmitted to the sand layer 5;
let the one-dimensional elastic wave have a wave impedance of ρ 2 c 2 E.g. the cover plate 7 propagates to another wave with an impedance p 3 c 3 For example, a sand layer 5, the propagation direction of the one-dimensional elastic wave is perpendicular to the interface, and the two media are always kept in contact at the interface, according to the continuous condition and newton's third law, the particle velocity and stress of the two sides of the interface after the transmission and reflection of the stress wave should be equal, so that:
V I +V R ＝V T (5)
σ I +σ R ＝σ T (6)
in the formula: v I Is the particle velocity, V, of the incident wave R The particle velocity, V, of the reflected wave T Is the particle velocity of the transmitted wave;
σ I is the particle stress, σ, of the incident wave R Is the particle stress, σ, of the reflected wave T Is the particle stress of the transmitted wave;
it is possible to obtain,
therefore, the temperature of the molten metal is controlled,
let σ be the attenuation of the stresses in the cover plate 7 not taken into account j ＝σ I The stress σ transmitted into the sand layer 5 T Comprises the following steps:
where ρ is 1 c 1 Wave impedance, p, of the material of the falling body 2 2 c 2 Wave impedance, p, of the material of the cover plate 7 3 c 3 The wave impedance of the sand and V the speed at which the falling body hits the concrete cover plate. ρ is a unit of a gradient 1 As falling body 2 material density, c 1 Wave velocity, p, of the material of the falling body 2 2 Is the density of the material of the cover plate 7, c 2 Is the wave velocity, p, of the material of the cover plate 7 3 Is the density of sandy soil material, c 3 The wave velocity of the sandy soil material is used, and g is the gravity acceleration;
s3: determining the lifting height of the falling body;
assuming that a falling body 2 with a mass m falls with a height h and a velocity when hitting the concrete cover plate 7 is V, there are, according to the conservation of energy:
the following can be obtained:
the lifting height h of the falling body is:
where ρ is 1 c 1 Wave impedance, p, of the material of the falling body 2 2 c 2 Wave impedance, p, of the material of the cover plate 7 3 c 3 Wave impedance, p, of sand 1 As falling body 2 material density, c 1 Wave velocity, p, of the material of the falling body 2 2 Is the density of the material of the cover plate 7, c 2 Is the wave velocity, p, of the material of the cover plate 7 3 Is the density of sandy soil material, c 3 The wave velocity of the sandy soil material is used, and g is the gravity acceleration; sigma T For the stresses transmitted into the sand layer 5, the peak value is σ max ，σ max The peak value of stress wave in the sandy soil is shown, and g is the gravity acceleration.
Step nine: setting the thickness of the cushion layer as H, lifting the falling body 2 to a preset position according to the lifting height H obtained in the step eight, and impacting the structural model 4 by using the falling body 2.
Preferably, the lifting mechanism 1 is used for lifting the falling body 2 to a preset position, the preset position is a lifting height h +/-100 mm, then the falling body 2 is released, the falling body 2 is made to fall, and the vertical uniform explosive load is simulated in a mechanical mode.
Step ten: and connecting the pressure sensor and the strain gauge to the broadband strain gauge and the transient recorder to obtain a pressure waveform diagram and a strain waveform diagram of the structure model 4.
Preferably, the dynamic pressure on the structural model 4 is measured, the pressure waveform diagram of the structural model 4 is obtained through the pressure sensor 9 in the sandy soil layer 5, and the strain waveform diagram of the structural model 4 is obtained through the strain gauge 10, so that the law of the dynamic load of explosion and the structural response is obtained.
Step eleven: comparing the waveform obtained by the pressure sensor with a preset waveform, and judging the relation between the pressure waveform obtained in the step ten and the preset waveform; the dynamic response of the main structure is ensured to be within a preset range through the waveform of the strain gauge, and the structure is prevented from being damaged;
if the pressure waveform in the step ten is not matched with the preset waveform, turning to the step twelve;
if the pressure waveform in the step ten is matched with the preset waveform, turning to a step thirteen;
step twelve: changing the thickness of the cushion layer above the cover plate and/or the lifting height of the falling body, and turning to the ninth step;
when the measured pressure waveform peak value is smaller than the preset waveform peak value, the height of the falling body is lifted;
when the measured pressure waveform pulse width is smaller than the preset waveform pulse width, increasing the thickness of the cushion layer;
preferably, the desired waveform is obtained by adjusting the elevation height of the falling body 2, the material of the cushion layer 6, and the thickness to adjust the peak value and pulse width of the waveform. After the data are obtained, explosion test can be carried out according to the data.
Step thirteen: and completing pressure waveform debugging, and performing a soil shallow-buried structure model test or an explosion remote zone component dynamic response test.
Meanwhile, the invention also provides a mechanical applying device for vertically and uniformly distributing the explosive load, which mainly comprises a structural model 4, a sand layer 5, a detection device, a falling body 2 and a lifting mechanism 1. The sand layer 5 is located above the structural model 4 and completely covers the top surface of the structural model 4. The detection device is arranged on the structure model 4 and the sand layer 5; the lifting mechanism 1 is positioned outside the structural model 4 and the sandy soil layer 5; the falling body 2 is mounted on the lifting mechanism 1 and is located above the sand layer 5. The lifting mechanism 1 comprises hydraulic equipment and four vertically arranged stand columns, a guide rail is arranged at the contact position of each stand column and the falling body 2, the guide rail can enable the falling body 2 to move up and down more conveniently, the falling body 2 is lifted through the hydraulic equipment, and then the falling body 2 falls along the guide rail 22 to impact the structural model 4.
According to the mechanical applying device for vertically and uniformly distributing the explosive load, disclosed by the invention, the falling body 2 vertically falls on the top surface of the sand layer 5 during the test, so that the load is transmitted to the structural model 4, and the detecting device can detect the pressure and the strain generated by the structural model 4, so that the relation between the load and the structural response is obtained. The invention applies vertically and uniformly distributed explosive load by using a mechanical mode, can meet the requirements of the test research of a shallow buried structure model in soil and the dynamic response test research of the component in the far explosion region, has simple structure, low cost and good repeatability, is particularly suitable for the principle experiment at the early stage of a project and finds the law of explosive dynamic load and structural response.
Further, in the invention, the bottom surface of the falling body 2 is a plane, and the area of the bottom surface is larger than the area of the top surface of the sand layer 5, namely the area of the top surface of the structural model 4, so that the requirement of simulating the vertically and uniformly distributed explosive load applied to the structural model 4 can be met. Preferably, the mass of the drop 2 is adjustable to meet the requirements for performing tests of different parameters. The lifting mechanism 1 is a hydraulic lifting mechanism and has a secondary impact prevention function, namely the falling body 2 is locked immediately after the bottom surface of the falling body 2 is contacted with an object, and the waveform interference caused by secondary impact of the falling body 2 can be eliminated.
Further, in the invention, the structural model 4 is a box structure, the enclosing structures 3 are arranged around the sand layer 5, the enclosing structures 3 can enclose the sand layer 5 above the structural model 4, the material of the sand layer 5 can be consistent with the soil body expected to bear the explosive load, and when the thickness is selected, the thickness of the actual sand is scaled proportionally according to the ratio between the structural model 4 and the actual structure. The detection means comprise a pressure sensor 9 and a strain gauge 10. Pressure sensor 9 is located sand layer 5, and a plurality of pressure sensor 9 distribute along vertical direction in sand layer 5, have the interval between two adjacent pressure sensor 9, can measure a plurality of position points, and then provide multiunit data. The strain gauge 10 is located inside the top wall of the structural model 4, the plurality of strain gauges 10 are distributed at the midspan position inside the top wall of the structural model 4, and the adjacent two strain gauges 10 have a gap therebetween, so that deformation of the structural model 4 can be detected.
Further, the invention further comprises a cover plate 7, wherein the cover plate 7 is positioned above the sandy soil layer 5 and in the enclosure structure 3, the top surface of the cover plate 7 is higher than that of the enclosure structure 3, and when the falling body 2 falls, the falling body can be completely hammered onto the cover plate 7 and is not in contact with the enclosure structure 3. According to the invention, the cover plate 7 is arranged, so that the load caused by the falling body 2 can be concentrated, and further, a concentrated and uniformly distributed load can be loaded on the sand layer 5.
Further, in the present invention, the pressure sensor further includes a cushion layer 6, the cushion layer 6 is located on the top surface of the cover plate 7, the cushion layer 6 is made of an elastic material, preferably rubber, and the pressure waveform and the strain waveform are further adjusted by adjusting the thickness of the cushion layer 6.
Furthermore, the invention further comprises a buffer layer 8, wherein the buffer layer 8 is positioned between the bottom surface of the cover plate 7 and the sandy soil layer 5, the buffer layer 8 is made of a foaming material, such as foamed polyurethane, foamed polyethylene and foamed rubber, and is provided with a plurality of holes which can play a role in buffering, noise waves generated by filtering can be filtered after the falling body 2 falls on the cover plate 7, that is, only strong impact waves can be transmitted into the sandy soil layer 5, and interference factors such as secondary collision are absorbed by the buffer layer 8, so that the test result is more accurate.
Further, in the present invention, the structural model 4 is any one of a reinforced concrete structure, a glass fiber reinforced plastic structure, and a steel structure; the enclosure structure 3 is a plate-shaped structure; the cover plate 7 is of any one of a steel structure and a reinforced concrete structure.
Examples
The structural model 4 is a box-shaped steel structure, the length of the structural model is 400mm, the width of the structural model is 360mm, the height of the structural model is 400mm, the structural model adopts densely-arranged square steel pipes with the length of 30mm multiplied by 1.5mm, the spacing is 55mm, the outer side of the structural model is coated with a steel plate with the thickness of 1mm, and the yield strength of the steel is 285 MPa.
The envelope 3 adopts the steel construction, and is high 200mm, and inside clear dimension is long 350mm, wide 300mm, and inside loads the sand bed 5. The buffer layer 8 is a polyethylene foam plate with the thickness of 40 mm. The cover plate 7 is made of reinforced concrete and has the thickness of 50mm, the length of 350mm and the width of 300 mm. The cushion layer 6 is made of rubber and has the same size as the cover plate 7.
The roof surface of structural model 4, roof upper surface sets up a pressure sensor 9 promptly to set up a pressure sensor 9 in sand 5, both vertical distances are 140mm, and the vertical distance of the pressure sensor 9 distance buffer layer 8 in the sand 5 is 50 mm. Three strain gauges 10 are provided on the inner surface of the top plate of the structural model 4, that is, the lower surface span of the top plate, and the interval between the center lines of two adjacent strain gauges 10 is 55 mm.
The falling body 2 is made of steel with the mass of 600kg +/-50 kg, the bottom surface is rectangular, and the length and the width of the falling body are both larger than 1000 mm.
Peak value sigma of stress wave in soil max Taking 2MPa rho 1 c 1 Take 4.05X 10 7 kg/m 2 ·s；ρ 2 c 2 Taking 9.8X 10 6 kg/m 2 ·s；ρ 3 c 3 Take 5.0X 10 5 kg/m 2 S, g is 9.8m/s 2 。
And calculating by adopting a formula of the estimated lifting height to obtain that the height of the falling body 2 is 350mm, and starting to perform test and debugging. The pressure waveform obtained at a height of 400mm of the falling body 2 is shown in FIG. 4, and the strain waveform is shown in FIG. 5.
It will be appreciated by those skilled in the art that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The embodiments disclosed above are therefore to be considered in all respects as illustrative and not restrictive. All changes which come within the scope of or equivalence to the invention are intended to be embraced therein.
Claims (8)
1. A mechanical application method for vertically and uniformly distributing explosive loads is characterized by comprising the following steps:
the method comprises the following steps: determining a structural model;
step two: arranging protective layers above the structural model; the protective layer comprises a sand layer, a cover plate and a cushion layer with adjustable thickness;
step three: judging whether a lifting mechanism for testing is provided with a secondary impact prevention device, wherein the secondary impact prevention device locks a falling body after the bottom surface of the falling body is contacted with an object, and eliminates waveform interference caused by secondary impact of the falling body;
if the lifting mechanism for the test is not provided with the secondary impact prevention device, turning to the fourth step;
if the lifting mechanism for the test is provided with the secondary impact prevention device, directly switching to the fifth step;
step four: a buffer layer is arranged between the cover plate and the sand layer;
step five: arranging a pressure sensor on the outer side wall of the top surface of the structural model, wherein the side wall and the top of the pressure sensor are both in contact with sand;
step six: disposing a plurality of strain gauges to an inner surface of a top surface of the structural model;
step seven: determining the falling body mass m, wherein the area of the bottom surface of the falling body is larger than that of the top surface of the sand layer, so that the falling body can be ensured to apply vertically and uniformly distributed load to the structural model when falling;
step eight: determination of the peak value sigma of a stress wave in the soil max Setting the lifting height of the falling body;
wherein the expression of the lift height h is as follows,
wherein σ max Is the peak value of the stress wave in the soil, rho 1 c 1 Wave impedance, p, of the material of the falling body 2 2 c 2 Wave impedance, p, of the material of the cover plate 7 3 c 3 Wave impedance of sand, p 1 As falling body 2 material density, c 1 Wave velocity, p, of the material of the falling body 2 2 Is the density of the material of the cover plate 7, c 2 Is the wave velocity, p, of the material of the cover plate 7 3 Is the density of sandy soil material, c 3 The wave velocity of the sandy soil material is adopted, and g is the gravity acceleration;
wherein the step of determining the lift height is as follows,
s1: after the falling body impacts the cover plate, calculating the stress sigma generated by the falling body on the contact surface of the falling body and the cover plate j ；
Obtaining the stress sigma generated on the contact surface of the cover plate according to the discontinuous wave sudden jump condition in the solid j ，
σ j ＝ρ 1 c 1 (V 1 -V)
σ j ＝-ρ 2 c 2 V 1
Where ρ is 1 c 1 Wave impedance of falling body material, p 2 c 2 Wave impedance, p, of cover material 1 Density of falling body material, c 1 Is the wave velocity, p, of the falling body material 2 Is the density of the cover material, c 2 Is the wave velocity of the cover sheet material; v is the speed of impact of the falling body on the concrete cover plate, V 1 Stress sigma generated on contact surface of cover plate for medium common speed movement on contact surface j Is the stress of the top surface of the cover plate, σ j ＝-ρ 2 c 2 V 1 In, "-" denotes a down-traveling wave;
it can be obtained that the stress σ generated on the contact surface of the cover plate j Comprises the following steps:
where ρ is 1 c 1 Wave impedance of falling body material, p 2 c 2 Is the wave impedance of the cover material; v is the speed of the falling body impacting the concrete cover plate; rho 1 As falling body material density, c 1 Is the wave velocity, p, of the falling body material 2 Is the density of the cover material, c 2 Is the wave velocity of the cover plate material;
s2: calculating the stress sigma generated on the contact surface of the cover plate j Stress transmitted to the sand layer;
one-dimensional elastic waves are transmitted to the sandy soil layer from the cover plate, wherein the wave impedance of the cover plate is rho 2 c 2 Sand layer with wave impedance rho 3 c 3 The propagation direction of the one-dimensional elastic wave is perpendicular to the interface, and the two media are always kept in contact with each other at the interface, so that the particle velocity and the stress of the two sides of the interface after the transmission and reflection of the stress wave are equal according to the continuous condition and Newton's third law,
V I +V R ＝V T
σ I +σ R ＝σ T
in the formula: v I Is the particle velocity, V, of the incident wave R Is the particle velocity, V, of the reflected wave T Is the particle velocity of the transmitted wave;
σ I is the particle stress, σ, of the incident wave R Is the particle stress, σ, of the reflected wave T Is the particle stress of the transmitted wave;
it is possible to obtain a solution of,
therefore, the temperature of the molten metal is controlled,
let σ be the attenuation of stress in the cover plate irrespective j ＝σ I Wherein the particle stress of the transmitted wave is the stress transmitted into the sandy soil layer, and the stress sigma transmitted into the sandy soil layer T Comprises the following steps:
wherein ρ 1 c 1 Wave impedance of falling body material, p 2 c 2 Is the wave impedance of the cover material, p 3 c 3 The wave impedance of the sand is shown, and V is the speed of the falling body impacting the concrete cover plate; rho 1 As falling body material density, c 1 Is the wave velocity, p, of the falling body material 2 Is the density of the cover material, c 2 Is the wave velocity, p, of the cover material 3 Is the density of sandy soil material, c 3 The wave velocity of the sandy soil material;
s3: determining the lifting height of the falling body;
let the drop with mass m fall with height h, the velocity when hitting the concrete cover plate 7 is V, according to the conservation of energy:
the following can be obtained:
the lifting height h of the falling body is:
where ρ is 1 c 1 Wave impedance of falling body material, p 2 c 2 Is the wave impedance of the cover material, p 3 c 3 Wave impedance of sand, p 1 As falling body material density, c 1 Is the wave velocity, p, of the falling body material 2 Density of cover material, c 2 Wave velocity, p, of the cover material 3 Is the density of sandy soil material, c 3 The wave velocity of the sandy soil material is adopted, and g is the gravity acceleration; sigma T For stresses transmitted into the sand layer, the peak value is σ max ，σ max The peak value of stress wave in sandy soil is shown, and g is gravity acceleration;
step nine: setting the thickness of the cushion layer to be H, lifting the falling body to a preset position according to the lifting height obtained in the step eight, and impacting a structural model by using the falling body;
step ten: connecting the pressure sensor and the strain gauge to a broadband strain gauge and a transient recorder to obtain a pressure oscillogram and a strain oscillogram of a structural model;
step eleven: comparing the waveform obtained by the pressure sensor with a preset waveform, and judging the relationship between the pressure waveform obtained in the step ten and the preset waveform; the dynamic response of the main structure is ensured to be within a preset range through the waveform of the strain gauge, and the structure is prevented from being damaged;
if the pressure waveform in the step ten is not matched with the preset waveform, turning to a step twelve;
if the pressure waveform in the step ten is matched with the preset waveform, turning to a step thirteen;
step twelve: changing the thickness of the cushion layer above the cover plate and/or the lifting height of the falling body, and turning to the ninth step;
when the measured pressure waveform peak value is smaller than the preset waveform peak value, the height of the falling body is lifted;
when the measured pressure waveform pulse width is smaller than the preset waveform pulse width, increasing the thickness of the cushion layer;
step thirteen: and completing pressure waveform debugging, and performing a soil shallow-buried structure model test or an explosion remote zone component dynamic response test.
2. A method of mechanically applying a vertically equipartition explosive load according to claim 1, characterized in that the strain gauges are provided in the midspan of the inner surface of the top surface of the structural model; the mid-span is located at a midline of the top surface parallel to the two side portions, along which the strain gage is disposed.
3. The method for mechanically applying a vertically uniform blast load as recited in claim 1, wherein a sand layer is disposed above said structural form, said sand layer is surrounded by said building envelope, said sand layer is provided with a cover plate, and said cover plate is provided with a bedding course.
4. A method of mechanically applying a vertically equipartitable explosive load according to claim 1, wherein the structural model comprises a top surface, a bottom surface and side surfaces forming a support between the top and bottom surfaces; the number of the side surfaces is two, and the two side surfaces are oppositely arranged, so that an opening is formed in the box-type structure, and the strain gauge is convenient to mount.
5. The method of claim 1, wherein the step of mechanically simulating the vertically distributed blast load comprises lifting the drop body with a lifting mechanism to a predetermined height h ± 100mm, and releasing the drop body to drop the drop body.
6. A method of mechanically applying a vertically equispaced explosive load according to claim 1 wherein the mass of the drop is selected to be above 200 kg.
7. A method of mechanically applying a vertically equipartition blast load according to claim 1, characterised in that the sandy soil layer comprises a plurality of pressure sensors; at least one pressure sensor is located on an exterior sidewall of the top surface of the structural model.
8. A method of mechanically applying a vertically equipartition explosive load according to claim 1, characterised in that pressure sensors are also provided inside the sand layer at the outer side walls not adjacent to the top surface of the structural model.
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