CN104569162A - Single-impact type vibration excitation device applicable to nondestructive tests of long anchor rods/long anchor cables - Google Patents

Abstract

The invention relates to a single-impact type vibration excitation device applicable to nondestructive tests of long anchor rods/long anchor cables. The device consists of a vibration excitation cone and a buffer device, wherein the vibration excitation cone adopts the structure of a two-section mechanism which comprises a vibration excitation cone body and a vibration excitation cone sharp end; the buffer device consists of a spring and a rubber pad; a step for accommodating the spring is arranged between the vibration excitation cone sharp end and the vibration excitation cone body, one end of the spring is fixed on the step, and the other end of the spring is connected with the rubber pad; the vibration excitation cone, the spring and the rubber pad are connected in series, mounted sequentially and kept to be concentric and in parallel. The device has the benefits as follows: low-frequency high-energy elastic wave signals can be produced, the test range and the working efficiency during quality tests on the long anchor rods and the long anchor cables are improved to a great extent, secondary vibration excitation can be effectively avoided, and the test precision is greatly improved; the device is simpler in overall structure and convenient to operate.

Description

A kind of one-shot formula exciting device being applicable to long anchor pole/long anchor cable Non-Destructive Testing

Technical field

The invention belongs to building, building, bridge, Quality of Water Conservancy Projects safety detection technology field, specifically refer to a kind of one-shot formula exciting device being applicable to long anchor pole/long anchor cable Non-Destructive Testing.

Background technology

In tunnel, side slope, in the engineerings such as colliery, in order to the ground of stable periphery, anchor pole, anchor cable get a lot of applications.But due to the impact such as weathering, underground water of Test in Situ, anchor cable, anchor pole unavoidably there will be various aging, degradation phenomena, reduce the stability of side slope, and then work the mischief and lose.Therefore quality testing is carried out to anchor pole (rope) and have its necessity and importance.

At present, in anchor pole (rope) quality testing, normal method makes exciting device carry out exciting in tested anchor pole (rope) termination, thus bring out elastic wave signal in anchor pole (rope) inside, reflected signal bottom pickup anchor pole (rope) bottom or leverage, and demarcate the length of the tested anchor pole of comprehensive descision (rope) by the amplification filtering of signal, time-domain spectral, frequency difference process and velocity of wave.Basic test principle as shown in Figure 1.

When testing long anchor pole or anchor cable, because whole tested object length is long, elastic wave energy has a large amount of losses in communication process, makes the faint even None-identified of bottom reflection signals.Therefore, when testing long anchor pole (rope), exciting source should select the device that can excite high-energy elastic wave, and the elasticity wavelength that this device generates will be grown, to reduce the decay of elastic wave.

The elasticity wave frequency that exciting device produces can be estimated by following method.

When exciting device is when exciting anchor pole (rope), whole exciting contact process is shown in Fig. 2, and the free running frequency characteristic that exciting causes is shown in Fig. 3, and the pass between them is

$f=\frac{1.25}{T_c}---(1-1)$

In formula, T _cfor the duration of contact in exciting process.

So want to reduce the elastic wave frequency produced, only have the duration of contact extended in exciting process.H.Hertz proposed towards elastomeric collision theory in 19th century.For the collision of spherical and semi-infinite plane, its duration of contact can be calculated by following formula:

$T_c=4.53{\left[\frac{({\mathrm{\δ}}_1+{\mathrm{\δ}}_2)m_1}{\sqrt{R_1{v}_0}}\right]}^{2/5}---(1-2)$

In formula, T _cfor duration of contact;

δ ₁, δ ₂be the parameter of related materials, calculating formula is e is deformation modulus;

M ₁it is the quality of hitting spheroid;

R ₁it is the radius hitting spheroid;

V ₀speed during spheroid generation exciting;

By above formula, can draw, want the duration of contact extending whole exciting process, so exciting device will adopt material deformation modulus little, the large and design that exciting position radius is little of quality.And select the exciting device that quality is large, also can the high-octane elastic wave of easier generation.

The peening hammer that analog computation is commonly used when exciting anchor pole, the size of theoretical excited frequency.Design conditions select as follows: the Bai Song of steel than δ=0.3, density p=7850kg/m ³, deformation modulus E=200GPa, supposes that hammer freely falls from 0.1m, impact velocity in the above conditions, choose the peening hammer that diameter is 17mm, 30mm and 50mm respectively, its theoretical excited frequency calculated is respectively:

f ₁₇＝7.6kHz,f ₃₀＝6.8kHz,f ₅₀＝4kHz。

As can be seen from result of calculation above, by increasing the diameter of exciting hammer, exciting elasticity wave frequency effectively can be reduced.But in the detection of reality, due to the area of section of anchor cable less (generally only having about 7mm), therefore, excessive exciting hammer has inconvenience in exciting.

Following table is the exciting characteristic comparing of existing conventional exciting device

The conventional exciting device comparison table of table-1

Summary of the invention

The object of the invention is to the deficiency overcoming prior art existence, and a kind of dust cap that effectively can reduce loss probability is provided.

The object of the invention is to have come by following technical solution, to be bored and snubber assembly forms by exciting, the structure of described exciting cone is two-part mechanism, and namely exciting cone and exciting bore sharp end, and described snubber assembly is made up of elastic spring and rubber blanket; Be provided with one between described exciting cone sharp end and exciting cone for placing the step of elastic spring, elastic spring one end is fixed on step, and the other end is connected with rubber blanket; Described exciting cone is connected with elastic spring, rubber blanket and is installed in order successively, and keeps concentric and parallel.

As preferably, described exciting cone is made up of metal material, wherein exciting cone sharp end knock end for conical, exciting cone sharp end invests in elastic spring intracardiac completely.

As preferably, described rubber blanket is connected with elastic spring, and rubber blanket edge stretches out from elastic spring center and surrounds the end of elastic spring completely.

Beneficial effect of the present invention is: can produce the high-octane elastic wave signal of low frequency, sensing range when improve long anchor pole, long anchor cable quality testing to a great extent and work efficiency, and effectively can avoid the generation of secondary exciting situation, substantially increase the precision of detection; One-piece construction is also comparatively simple, easy to operate.

Accompanying drawing explanation

Fig. 1 is existing anchor pole (rope) basic test schematic diagram.

Fig. 2 is existing exciting process linear graph.

Fig. 3 is existing vibration frequency characteristics linearity figure.

Fig. 4 is common exciting wimble structure schematic diagram of the present invention.

Fig. 5 is hand-held common exciting cone exciting process schematic of the present invention.

Fig. 6 is 25m long anchor cable of the present invention common exciting cone test waveform figure.

Fig. 7 is one-shot formula exciting of the present invention cone using state schematic diagram.

Fig. 8 is the long anchor pole of 12M of the present invention common exciting cone test waveform figure.

Fig. 9 is 12M of the present invention long anchor pole one-shot formula exciting cone test waveform figure.

Figure 10 is one-shot formula exciting of the present invention cone front-end architecture schematic diagram.

Figure 11 is one-shot formula exciting wimble structure schematic diagram of the present invention.

Label in accompanying drawing is respectively: 1, exciting cone; 2, snubber assembly; 11, exciting cone; 12, exciting cone sharp end; 13, step; 21, elastic spring; 22, rubber blanket.

Embodiment

Below in conjunction with accompanying drawing, detailed introduction is done to the present invention: as shown in accompanying drawing 10,11, the present invention is made up of exciting cone 1 and snubber assembly 2, the structure of described exciting cone 1 is two-part mechanism, i.e. exciting cone 11 and exciting cone sharp end 12, described snubber assembly 2 is made up of elastic spring 21 and rubber blanket 22; Be provided with one between described exciting cone sharp end 12 and exciting cone 11 for placing the step 13 of elastic spring 21, elastic spring 21 one end is fixed on step 13, and the other end is connected with rubber blanket 22; Described exciting cone 1 is connected install in order successively with elastic spring 21, rubber blanket 22, and keeps concentric and parallel; Recommend the steel wire diameter 1.6mm of elastic spring 21, elastic spring 21 diameter 16mm.

Described exciting cone 1 is made up of metal material, and wherein the end that knocks of exciting cone sharp end 12 is conical, and exciting cone sharp end 12 invests in elastic spring 21 intracardiac completely.

Described rubber blanket 22 is connected with elastic spring 21, and rubber blanket 22 edge stretches out from elastic spring 21 center and surrounds the end of elastic spring 21 completely.

1), based on the excitor (exciting cone 1) that impact theory is optimized

According to Hertz impact theory, the elastic wave signal of long wavelength be expected, need:

(1) excitor quality m ₁greatly;

(2) radius R of striking part ₁little;

In order to solve this contradiction, exciting device is designed to the form (Fig. 4) of exciting cone by us.It meets the requirement that total quality is large, exciting cone leading portion radius-of-curvature is little.

Test findings shows (table 2), and the signal frequency that exciting cone produces has obvious reduction, and its convergence, consistance etc. are all better simultaneously.

The comparison table of table-2 exciting cone

1) device (snubber assembly 2) of exciting, is prevented repeatedly

But, the existing picture of secondary exciting is usually there is when using exciting cone, the reason producing this problem mainly people when hand-held exciting cone carries out exciting (see Fig. 5), after having knocked, in order to keep the balance of this hammer action and maintenance human body self, human body natural has an inertial force and acts on exciting cone, causes secondary exciting phenomenon.

Secondary exciting detects anchor pole (rope), and particularly long anchor pole (rope) detects is totally unfavorable.Secondary exciting signal is mixed into normal signal, causes signal to produce irregular mutation, makes troubles to the identification of normal bottom reflection signals, even can the identification of misleading signals time serious, causes the substantial deviation of testing result and actual conditions.

Fig. 6 is the actual test waveform of certain 25m long anchor cable, and overall waveform convergence signal is good, and reflected signal is obvious, but has secondary exciting situation to produce in test.It is 24m that regular reflection signal location calculates anchor cable length, and test result is satisfactory.If but be reflected signal by secondary exciting Signal analysis above, the result so calculated is only 8.88m, with actual conditions substantial deviation.

The present invention solves above-mentioned secondary exciting problem by increasing snubber assembly 2 before above-mentioned exciting cone 1 exactly; Offset, cushion human body knock after inertia behavior, and then overcome exciting cone test long anchor pole (rope) time produce secondary exciting signal.Fig. 7 is the schematic diagram of device.

Apparatus of the present invention are utilized to carry out the step of exciting as follows:

1), by rubber blanket 22 on the exciting cone sharp end 12 of one-shot formula exciting cone 1 be placed on the cross section of anchor pole or anchor cable, and make exciting bore the axis of 1 and the axis being parallel of anchor pole (rope);

2), mode that is artificial or electromagnetism produce one moment thrust, make exciting bore 1 and rush at anchor pole or anchor cable;

3), after exciting cone 1 collides with anchor pole or anchor cable, should weaken or cancel secondary exciting power.

Fig. 8 does not add the signal that the long anchor pole of 12m tested by snubber assembly 2, can find out, occur the signal of 2 excitings in test signal.

Fig. 9 with the addition of the signal that the long anchor pole of 12m tested by snubber assembly 2, can find out in test signal, do not have the signal of 2 excitings, thus substantially increases quality and the measuring accuracy of accumulation signal.

Be understandable that, for a person skilled in the art, technical scheme of the present invention and inventive concept be equal to and replace or change the protection domain that all should belong to the claim appended by the present invention.

Claims (3)

1. one kind is applicable to the one-shot formula exciting device of long anchor pole/long anchor cable Non-Destructive Testing, be made up of exciting cone (1) and snubber assembly (2), it is characterized in that: the structure of described exciting cone (1) is two-part mechanism, i.e. exciting cone (11) and exciting cone sharp end (12), described snubber assembly (2) is made up of elastic spring (21) and rubber blanket (22); One is provided with for placing the step (13) of elastic spring (21) between described exciting cone sharp end (12) and exciting cone (11), elastic spring (21) one end is fixed on step (13), and the other end is connected with rubber blanket (22); Described exciting cone (1) is connected install in order successively with elastic spring (21), rubber blanket (22), and keeps concentric and parallel.

2. the one-shot formula exciting device being applicable to long anchor pole/long anchor cable Non-Destructive Testing according to claim 1, it is characterized in that: described exciting cone (1) is made up of metal material, wherein the end that knocks of exciting cone sharp end (12) is conical, and exciting cone sharp end (12) invests in elastic spring (21) intracardiac completely.

3. the one-shot formula exciting device being applicable to long anchor pole/long anchor cable Non-Destructive Testing according to claim 1, it is characterized in that: described rubber blanket (22) is connected with elastic spring (21), rubber blanket (22) edge stretches out from elastic spring (21) center and surrounds the end of elastic spring (21) completely.