CN106940275B - A plate fixture platform for drop weight impact test and impact speed measurement method - Google Patents

Abstract

The invention discloses a plate clamp platform for a drop weight impact test and an impact speed measurement method, which include a clamp structure, a supporting lifting structure and a laser sensor. The clamp structure includes a plate clamping device, a multi-angle rotation device and a clamp base plate; the multi-angle rotation device includes a wall plate, wall plate bolts and bottom plate bolts; each wall plate is provided with a center hole and two arc-shaped slots, two The arcuate groove is symmetrical about the central hole; when the wall plate bolts are all loosened, the splint can rotate along the arcuate groove; the supporting lifting structure includes a platform and a lifting drive device, and the fixture base plate can rotate around the base plate bolts and can rotate along the base plate bolts. The straight hole slides; the laser sensor is placed under the weight plate located on the outer periphery of the hammer head. The invention can provide a tight clamping for the composite plate test piece, and can also realize multi-angle impact on the test piece. At the same time, it can also measure the speed change of the falling weight in real time during the falling and impact process.

Description

A plate fixture platform for drop weight impact test and impact speed measurement method

Technical field

The invention relates to the field of material mechanical property testing, in particular to a plate fixture platform for drop weight impact testing and an impact speed measurement method.

Background technique

At present, in the process of testing the mechanical properties of composite materials, it is essential to test the impact resistance of composite materials. To test and evaluate the impact resistance of composite materials, it is generally necessary to conduct a drop weight impact test on composite plate test pieces. In the drop weight impact test, it is required to achieve fixed clamping of the plate test piece and collect the speed-time change curve during the falling weight and impact process.

In the existing general drop weight impact test of composite material panels, the drop weight in the drop weight impact device is dropped vertically and directly impacts the center position of the specimen clamped on the test bench of the drop weight impact device, thereby studying the specimen. The mechanical response of the material at the moment of frontal impact and the residual strength after the impact are used to evaluate the impact resistance of the material. After this kind of drop weight impact device clamps the test piece, most of them can only achieve frontal impact testing. It is difficult to achieve multi-angle drop weight impact testing on one drop weight impact device. At the same time, the clamping device is generally fixed and installed on the drop weight. Most of the impact devices can only achieve impact at a fixed position of the specimen, and it is difficult to achieve impact at different impact positions.

At the same time, in the existing drop weight impact test of composite material plates, gratings or laser checkpoints are generally used to collect two time points of the impact instant, and the average speed of this section is calculated based on the time change as the impact instant speed, and then combined with The impact force-time change curve measured by the force sensor is calculated through the mechanical formula to obtain the speed-time change curve during the impact process. Since this method calculates the average speed and uses two sensors, light and force sensors, the calculation accuracy is low and the calculation process is complicated. In addition, when performing an angled impact test, the lateral force and friction caused by the angle will seriously affect the measurement accuracy of the force sensor and make it more difficult to obtain the velocity-time curve.

Contents of the invention

The technical problem to be solved by the present invention is to provide a plate fixture platform for a drop weight impact test in view of the above-mentioned deficiencies in the prior art. The plate fixture platform for a drop weight impact test can provide a fastening clamp for the composite plate test piece. It can also achieve multi-angle impact on the test piece, and at the same time, it can also measure the speed change of the falling weight in real time during the falling and impact process.

In order to solve the above technical problems, the technical solution adopted by the present invention is:

A plate clamp platform for drop weight impact testing, including a clamp structure, a supporting lifting structure and a laser speed measuring device.

The clamp structure includes a plate clamping device, a multi-angle rotating device and a clamp base plate.

The plate clamping device includes a splint and a clamping piece; a specimen impact groove is provided in the center of the splint, and the clamping pieces are arranged on the plywood on both sides of the specimen impact groove, and the clamping piece and the plywood are detachably connected.

The multi-angle rotation device includes wall plates, wall plate bolts and bottom plate bolts; one wall plate is provided on each side of the splint, each wall plate is arranged vertically, and the bottom of each wall plate is fixedly connected to the bottom plate of the fixture; each wall plate The boards are provided with a central hole and two arc-shaped grooves, and the two arc-shaped grooves are symmetrical with respect to the central hole; the central hole and each arc-shaped groove are each provided with a wall for detachably connecting the wall plate and the plywood. Plate bolts, the wall plate bolts located in the arc-shaped groove can slide along the arc-shaped groove and be locked; when the wall plate bolts are all loosened, the splint can rotate along the arc-shaped groove.

The support lifting structure includes a platform and a lifting drive device. The platform can be raised and lowered under the action of the lifting drive device; a straight hole is provided in the middle of the platform along the length direction, and the bottom plate of the fixture is detachably connected to the platform through bottom plate bolts; the heads of the bottom plate bolts Located above the bottom plate of the fixture, the rods of the bottom plate bolts pass through the bottom plate of the fixture and the straight holes in sequence, and can slide along the straight holes and be locked and fixed; when the bottom plate bolts are loosened, the bottom plate of the fixture can rotate around the bottom plate bolts. , and can slide along the straight hole.

The drop weight is set above the fixture structure. The drop weight includes a weight, a weight plate and a hammer head arranged coaxially from top to bottom; the weight plate and the hammer head are fixedly connected, and the bottom of the hammer head points towards the specimen on the plywood for impact. groove.

The laser speed measuring device includes a laser sensor and a computer connected to the laser sensor. The laser sensor is arranged below the weight plate located on the outer periphery of the hammer head.

Each arc groove is a 1/4 arc groove.

At least one arc-shaped groove is provided with an angle scale mark.

The lifting drive device includes a base, a screw rod, a hinge and a hinge driving device. There are at least two screw rods. The middle part of each screw rod is threadedly connected to the platform, and the bottom of each screw rod is rotationally connected to the base. The hinge is connected to all the screw rods, and driven by the hinge driving device, the hinge drives all the screw rods to rotate synchronously.

The hinge driving device is a handle or a motor.

The present invention also provides a method for measuring impact velocity using a plate fixture platform for a drop weight impact test. The method for measuring impact speed using a plate fixture platform for a drop weight impact test can provide a tight clamp for composite material plate test pieces. It can also achieve multi-angle impact on the test piece, and at the same time, it can also measure the speed change of the falling weight in real time during the falling and impact process.

A method for measuring impact velocity using a plate fixture platform for a drop weight impact test, including the following steps.

Step 1. Adjust the height of the platform: start the lifting drive device to lower the height of the platform.

Step 2, test piece clamping: Place the composite plate standard test piece above the square slot of the plywood, and clamp the test piece through the clamping piece and the plywood fastening bolts.

Step 3. Adjust the impact angle: First, determine the impact angle a for this test as needed; then, loosen all wall plate bolts, rotate the splint to angle a, and tighten the wall plate bolts.

Step 4. Mark the impact point position: First, determine the impact position in this test as needed; then, take the center of the test piece as the origin. At this time, the bottom of the hammer head points to the origin; then, record the extreme position of the impact point. The coordinates are (m, n), and the impact point position is marked on the test piece with a marker.

Step 5. Adjust the impact point position: Loosen the base plate bolts, move the clamp base plate to the left a distance m, and then rotate it clockwise by an angle n so that the impact point position marked in step 4 is directly under the hammer head.

Step 6: The position of the hammer head coincides with the impact point: start the lifting drive device, raise the height of the platform until the test piece contacts the hammer head, and make the contact surface between the hammer head and the plate coincide with the impact point position marked in step 4, and then Tighten the base plate bolts.

Step 7. Adjust the position of the laser sensor: Place the laser sensor on the base, turn on the laser sensor and transmit the data to the computer through the data line. Adjust the position of the laser sensor so that the laser sensor is located under the weight plate around the hammer head.

Step 8, laser speed measurement: Clear the laser sensor data and conduct the impact test; the laser sensor will measure the instantaneous speed of the weight disk in real time during the impact process, and the computer will automatically record and draw the impact speed and time curve.

After the present invention adopts the above structure and method, it can not only provide a tight clamping for the composite plate test piece, but also realize multi-angle impact on the test piece. After the test piece is fastened, the impact position of the test piece can also be measured. Adjustment improves the flexibility and convenience of test operations. In addition, through the design of the fixture platform structure and the installation of laser sensors, the speed changes of the falling weight during the falling process are collected in real time by the laser shooting from the bottom up to the hammer head, and the falling weight is prevented from colliding with the laser sensor during the falling process. It provides real-time measurement of the speed change during the falling and impact process of the falling weight, improves the convenience of measurement, improves the measurement accuracy through single sensor data, and avoids the difficulty in obtaining the speed-time change curve caused by angular impact. The specific effect analysis is as follows:

1. By assembling the threaded rods protruding from the upper and lower splints and the hole grooves on the left and right wall plates, the plate clamping device can be rotated within the range of 0-90 degrees. By rotating the plate clamping device, the plate clamping device can be rotated within the range of 0-90 degrees. Drop hammer impact at any impact angle within 90 degrees;

2. By assembling the screw rod protruding from the bottom of the base plate and the long slot of the platform, the translation and rotation of the fixture structure can be realized. By adjusting the translation distance and rotation angle, the drop weight impact can be achieved at any position on the surface of the specimen;

3. Compared with using a combination of grating sensor and force sensor to measure the speed change of the impact process, using a single laser sensor improves the test reliability;

4. Compared with using a grating sensor to collect the average speed within the time interval of the impact instant, and then combining the force sensor data to overturn the method of calculating the speed of the impact process through mechanical formulas, using a laser sensor to measure the speed in real time reduces the difficulty of test data processing. , improve the measurement accuracy;

5. By dividing the box into upper and lower parts, the collision with the laser sensor during the falling weight is effectively avoided and the test safety is improved;

6. By using a lifting platform to adjust the space between the upper and lower boxes, the replacement and disassembly of the test piece is facilitated, and the installation of the laser sensor is facilitated.

Description of drawings

Figure 1 shows a schematic structural diagram of a plate fixture platform for drop weight impact testing according to the present invention.

Figure 2 shows a top view of the drop weight of the present invention.

Figure 3 shows a front view of the drop weight of the present invention.

Among them are: 1. Clamp; 2. Splint; 21. Specimen impact groove; 3. Plate fastening bolt; 4. Wall plate; 41. Center hole; 42. Arc groove; 5. Drop weight; 51. Hammer Head; 52. Weight plate; 53. Weight; 54. Hammer rod; 55. Nut; 6. Wall plate bolt; 7. Clamp bottom plate; 8. Platform; 81. Straight hole; 9. Bottom plate bolt; 10. Lead screw; 11. Hinge; 12. Handle; 13. Laser sensor; 14. Box; 141. Base.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific preferred embodiments.

As shown in Figure 1, a plate fixture platform for drop weight impact testing includes a fixture structure, a support lifting structure and a laser speed measurement device.

The clamp structure includes a plate clamping device, a multi-angle rotating device and a clamp base plate 7.

The plate clamping device includes a clamp 1, a clamping plate 2 and a clamping plate fastening bolt 3.

The thickness of the splint 2 is at least 20mm, and the recommended size is 25mm. There is a specimen impact groove 21 at the center of the splint 2. The specimen impact groove 21 is preferably a square groove of 150mm*100mm and a depth of 4mm.

The clamps are arranged on the splints on both sides of the impact groove of the specimen, and the clamps and the splints are detachably connected. Each clip is preferably threadedly connected to the plywood through three plywood fastening bolts.

The multi-angle rotation device includes wall plate 4, wall plate bolts 6 and bottom plate bolts 9.

A wall plate is provided on each side of the clamping plate, each wall plate is arranged vertically, and the bottom of each wall plate is fixedly connected to the clamp bottom plate 7, preferably by welding.

Each wall plate is provided with a central hole 41 and two arc-shaped grooves 42, the two arc-shaped grooves are symmetrical with respect to the central hole; a center hole 41 and each arc-shaped groove are respectively provided with a hole for connecting the wall plate and the plywood. Detachably connected wall plate bolts, the wall plate bolts located in the arcuate groove can slide along the arcuate groove and be locked; when the wall plate bolts are all loosened, the splint can rotate along the arcuate groove.

Each arc-shaped groove is preferably a 1/4 arc groove, that is, the splint can rotate 90° along the arc-shaped groove.

Further, at least one arc-shaped groove is provided with an angle scale mark.

The supporting lifting structure includes a platform 8 and a lifting driving device. The platform can be highly lifted and lowered under the action of the lifting driving device.

A straight hole 81 is provided in the middle of the platform along the length direction, and the bottom plate of the fixture is detachably connected to the platform through bottom plate bolts; the head of the bottom plate bolt is located above the bottom plate of the fixture, and the stem of the bottom plate bolt passes through the bottom plate of the fixture and the straight hole in sequence, and can Slide along the straight hole and lock and fix; when the bottom plate bolt is loosened, the fixture bottom plate can rotate around the bottom plate bolt and slide along the straight hole.

The drop weight is arranged above the clamp structure, as shown in Figures 2 and 3. The drop weight includes a weight 53, a weight plate 52 and a hammer head 51 arranged coaxially from top to bottom.

The hammer head is preferably integrated with the hammer rod 54, the weight plate and the hammer head are fixedly connected, and the weight is set on the hammer rod located above the weight plate; the bottom of the hammer head points to the specimen impact groove on the plywood.

The above-mentioned lifting driving device preferably includes a base 141, a screw rod 10, a hinge 11 and a hinge driving device.

The base 141 is preferably the bottom plate of the box 14. The five upper, lower, left, right and rear surfaces of the box 14 are closed surfaces, and the front is an open surface. The platform 8 preferably divides the box 14 into upper and lower parts, effectively avoiding the impact of the falling weight during the falling process. Collision with the laser sensor improves test safety.

There are at least two screw rods, preferably two screw rods in the present invention.

The middle part of each screw rod is threadedly connected to the platform, the bottom of each screw rod is rotationally connected to the base, and the hinge is connected to all the screw rods. The hinge drives all the screw rods to rotate synchronously under the drive of the hinge driving device.

The hinge driving device is a handle 12 or a motor, etc. The hinge forms a triangle around the screw and the handle; the screw is threadedly connected to the platform.

The laser speed measuring device includes a laser sensor 13 and a computer connected to the laser sensor. The laser sensor is arranged below the weight plate located on the outer periphery of the hammer head. The laser sensor includes a laser transmitter and a laser receiver.

A method for measuring impact velocity using a plate fixture platform for a drop weight impact test, including the following steps.

Step 1. Adjust the height of the platform: start the lifting drive device to lower the height of the platform.

Step 2, test piece clamping: Place the composite plate standard test piece above the square slot of the plywood, and clamp the test piece through the clamping piece and the plywood fastening bolts.

The size of the standard test piece of composite material plate is preferably 150mm*100mm*5mm.

Step 3. Adjust the impact angle: First, determine the impact angle a for this test as needed; then, loosen all wall plate bolts, rotate the splint to angle a, and tighten the wall plate bolts.

Step 4. Mark the impact point position: First, determine the impact position in this test as needed; then, take the center of the test piece as the origin. At this time, the bottom of the hammer head points to the origin; then, record the extreme position of the impact point. The coordinates are (m, n), and the impact point position is marked on the test piece with a marker.

Step 5. Adjust the impact point position: Loosen the base plate bolts, move the clamp base plate to the left a distance m, and then rotate it clockwise by an angle n so that the impact point position marked in step 4 is directly below the hammer head.

Step 6: The position of the hammer head coincides with the impact point: start the lifting drive device, raise the height of the platform until the test piece contacts the hammer head, and make the contact surface between the hammer head and the plate coincide with the impact point position marked in step 4, and then Tighten the base plate bolts.

Step 7. Adjust the position of the laser sensor: Place the laser sensor on the base, turn on the laser sensor and transmit the data to the computer through the data line. Adjust the position of the laser sensor so that the laser sensor is located under the weight plate around the hammer head.

Step 8, laser speed measurement: Clear the laser sensor data and conduct the impact test; the laser sensor will measure the instantaneous speed of the weight disk in real time during the impact process, and the computer will automatically record and draw the impact speed and time curve.

The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention. These equivalent transformations All belong to the protection scope of the present invention.

Claims (4)

1. A method for measuring impact speed by using a plate clamp platform for drop hammer impact test is characterized in that:

the plate clamp platform for the drop hammer impact test comprises a clamp structure, a supporting lifting structure and a laser speed measuring device;

the clamp structure comprises a plate clamping device, a multi-angle rotating device and a clamp bottom plate;

the plate clamping device comprises a clamping plate and a clamping piece; the center of the clamping plate is provided with a test piece impact groove, the clamping pieces are arranged on the clamping plates on two sides of the test piece impact groove, and the clamping pieces are detachably connected with the clamping plates;

the multi-angle rotating device comprises a wallboard, a wallboard bolt and a bottom plate bolt; the two sides of the clamping plate are respectively provided with a wall plate, each wall plate is vertically arranged, and the bottom of each wall plate is fixedly connected with the bottom plate of the clamp; each wall plate is provided with a central hole and two arc-shaped grooves, and the two arc-shaped grooves are symmetrical about the central hole; each arc groove is a 1/4 arc groove, and the clamping plate can rotate 90 degrees along the arc groove;

the center hole and each arc groove are respectively provided with a wallboard bolt used for detachably connecting the wallboard with the clamping plate, and the wallboard bolts positioned in the arc grooves can slide along the arc grooves and be locked; when the wallboard bolts are completely unscrewed, the clamping plate can rotate along the arc-shaped groove;

the supporting lifting structure comprises a platform and a lifting driving device, and the platform can be lifted up and down highly under the action of the lifting driving device; the middle part of the platform is provided with a straight hole along the length direction, and the clamp bottom plate is detachably connected with the platform through a bottom plate bolt; the head of the bottom plate bolt is positioned above the clamp bottom plate, and the rod part of the bottom plate bolt sequentially penetrates through the clamp bottom plate and the straight strip hole and can slide along the straight strip hole and be locked and fixed; when the bottom plate bolt is unscrewed, the clamp bottom plate can rotate by taking the bottom plate bolt as a center and can slide along the straight strip hole;

the drop hammer is arranged above the clamp structure and comprises weights, weight trays and hammerheads which are coaxially arranged in sequence from top to bottom; the weight tray is fixedly connected with the hammer head, and the bottom of the hammer head points to a test piece impact groove on the clamping plate;

the laser speed measuring device comprises a laser sensor and a computer connected with the laser sensor, and the laser sensor is arranged below a weight disc positioned on the periphery of the hammer head;

the measuring method comprises the following steps:

step 1, adjusting the height of a platform: starting a lifting driving device to reduce the height of the platform;

step 2, clamping a test piece: placing a standard test piece of the composite material plate above the square groove of the clamping plate, and clamping the test piece through the clamping piece and the clamping plate fastening bolt;

step 3, impact angle adjustment: firstly, determining an impact angle a of the test according to the requirement; then, loosening all the wallboard bolts, and tightening the wallboard bolts after rotating the clamping plate to an angle a;

step 4, marking the impact point positions: firstly, determining the impact position in the test according to the requirement; then, taking the center position of the test piece as an origin, and pointing the bottom of the hammer head to the origin at the moment; then, the polar coordinates of the impact point positions are recorded as (m, n), and the impact point positions are marked on the test piece by using a marker;

step 5, adjusting the impact point position: unscrewing a bottom plate bolt, moving a clamp bottom plate leftwards by a distance m, and then rotating clockwise by an angle n to enable the impact point marked in the step 4 to be right below the hammer head;

step 6, overlapping the hammer head and the impact point position: starting a lifting driving device, lifting the platform until the test piece contacts the hammer head, enabling the contact surface of the hammer head and the plate to coincide with the position of the impact point marked in the step 4, and then screwing the bottom plate bolt;

step 7, laser sensor position adjustment: the laser sensor is arranged on the base, the laser sensor is turned on, data are transmitted to the computer through the data line, and the position of the laser sensor is adjusted to enable the laser sensor to be positioned below the weight disc on the periphery of the hammer head;

step 8, laser speed measurement: resetting the laser sensor data, and performing an impact test; the laser sensor measures the instant speed of the weight tray in real time in the impact process, and the computer automatically records and draws the impact speed and time curve.

2. The method for measuring impact velocity using a plate holder platform for drop hammer impact test according to claim 1, wherein: at least one arc groove is provided with angle scale marks.

3. The method for measuring impact velocity using a plate holder platform for drop hammer impact test according to claim 1, wherein: the lifting driving device comprises a base, at least two screw rods, a hinge and a hinge driving device, wherein the middle part of each screw rod is in threaded connection with the platform, the bottom of each screw rod is in rotary connection with the base, the hinge is connected with all screw rods, and the hinge drives all screw rods to synchronously rotate under the driving of the hinge driving device.

4. A method of measuring impact velocity using a panel clamp platform for drop hammer impact test according to claim 3, wherein: the hinge driving device is a handle or a motor.