EP1913356A1

EP1913356A1 - Method and device for testing the stability and/or bending strength of masts

Info

Publication number: EP1913356A1
Application number: EP06762785A
Authority: EP
Inventors: Sven Homburg; Günter Jost
Original assignee: LGA Beteiligungs GmbH
Current assignee: LGA Beteiligungs GmbH
Priority date: 2005-08-09
Filing date: 2006-07-24
Publication date: 2008-04-23
Also published as: WO2007017090A1; US20080223134A1; DE102005038033A1

Abstract

The invention relates to a method and a device (10) for testing the stability and/or bending strength of masts (11), especially non-guyed masts (11). According to said method, a) the test is performed dynamically, b) the mast (11) being excited by means of an artificially generated force so as to perform movements, particularly vibrations, and c) the movements of the mast (11) are determined with the aid of one or several sensors (acceleration sensors, (13, 14)) which are disposed on the mast (11) and detect acceleration values in the respective position thereof on the mast (11). The inventive device (10) comprises a) an unbalance exciter (12) which is or can be placed on the mast (11), especially along the top third of the mast height (h), in order to generate a force, particularly a periodic force, affecting the mast (11) that is to be tested, b) one or several acceleration sensors (13, 14) which are or can be disposed on the mast (11) to detect acceleration values, and c) an evaluation unit (21) for determining the stability and/or the bending strength and/or flaws of the mast (11) that is to be tested.

Description

Description Method and device for checking the standing and / or

Flexural strength of masts

description

The invention relates to a method and a device for testing the stability and / or bending strength of masts, in particular masts not braced.

The term mast is generally understood to mean an elongated object, in particular in the manner of a rod, which is anchored or fixed to one long end, the mast foot, while the opposite long end, the mast tip, usually stands freely in the room. The mast is usually anchored or fixed to the base of the mast, for example in a foundation. The mast is then usually vertical. Anchoring to a wall is also possible.

The masts to be tested can be used for any purpose, for example as masts for power or telephone lines, railway masts, antenna masts, flagpoles, λ loads from wind turbines, lampposts and traffic light masts and / or traffic signs. Masts made of all conceivable materials can also be tested, for example masts made of wood, plastic, concrete and / or metal.

Masts usually have a circular or oval cross-section, but other cross-sectional shapes, for example angular (e.g. square or rectangular) cross-sections, are also possible. The diameter of the mast can be constant over the entire height, but it can also change along the mast, in particular its diameter can decrease from the mast base to the mast tip.

Both masts made of solid material and masts with an inner cavity are known. The masts are delimited laterally outwards by side surfaces, the side surface in the case of round and oval masts being able to be referred to as the outer surface

The anchoring of the mast base usually has to ensure the stability of the mast as an additional safeguard. Anchoring of the mast, especially at the mast tip, is known. However, this security measure is ruled out in many cases, for example due to space constraints (e.g. in towns or cities) in road traffic) or if there is no or no fixation options for guy ropes or rods.

Masts are continuously exposed to weather, especially wind. In order to withstand the forces acting on them and not topple over or buckle, the masts, in particular the masts that are not braced, must therefore have sufficient stability and bending strength. However, these properties in particular can deteriorate over time due to the numerous environmental influences to which masts are exposed, such as moisture, temperature fluctuations, solar radiation and industrial or traffic emissions, in particular due to material fatigue in the mast or anchoring (foundation).

A reduced stability and / or bending strength increases the risk of an accident due to a falling or kinking mast. This can be prevented by regularly checking the stability and / or bending strength.

In addition, a corresponding test can be useful immediately after production or when repositioning a mast (zero measurement) in order to determine manufacturing, material and / or anchoring errors right at the start.

From DE 94 04 664 U l and EP 0 638 794 B l a method and a device for testing the stability and bending strength of masts is known. A test piece is exposed to a variable bending moment by being loaded with a force that is introduced above its anchoring and increases during the test process. Sensors simultaneously measure the force and the distance by which the mast is laterally deflected at a selected point due to the bending moment. From the development of the ratio of these two values to one another up to a nominal test load, it is concluded whether the mast has sufficient strength or not.

Further training on this subject, which also includes a statement about a

Crack freedom or cracking of the mast is to be achieved is known from DE 296 07 045 U l. Here, tensile and compressive forces are introduced into the mast above its anchoring in order to load the mast with opposing bending moments. From the comparison of the determined force-displacement characteristics in the case of pressure loads and tensile loads or from a comparison with reference values, a conclusion is drawn that the mast is cracked.

A comparable device is known from DE 1 00 62 795 A1. These methods and devices basically work with a quasi static force, for which the mast deflection is measured in response. This static state is measured one after the other for different forces, so that a force-distance characteristic is obtained which is used for a corresponding evaluation. However, the d) namic reaction that occurs in practice to natural forces, for example due to wind, is not recorded and is therefore not available for evaluation

The practical d) load on the mast, d. H. However, the vector addition of an external force, such as wind or earthquake, plus the internal forces resulting from the dynamic nature of the vibrating mast is not recognized and is therefore not available for evaluation.

Another disadvantage of these methods and devices lies in the fact that the mast has to be subjected to forces for the assessment of sufficient strength which at least correspond to the expected maximum loads and even have to go far beyond them. For example, a static maximum load with 1.5 times the wind load is useful. These artificial, static loads can lead to an overload of the mast and thus to damage to the mast or its anchoring (foundation).

DE 102 29 448 A1 discloses a device for checking the stability of a mast anchored in the ground, in which a vibration sensor is permanently fixed to the mast. The vibration excitation occurs exclusively through the natural load of the mast by wind and weather. If the vibrations of the mast differ in terms of frequency, amplitude or form of vibration from a specified standard, this is taken as an indication of a mast error. The test is only understood as a preliminary test, which should lead to a comprehensive control if the result is appropriate.

The advantage of the latter device is the reduction in the number of masts to be checked. The results are, however, only to be regarded as an indication, however, this device cannot provide a reliable statement about the stability and bending strength.

It is the object of the invention to provide a method and a device for testing the stability and / or bending strength of masts which overcome the above-mentioned parts of the prior art. This task is solved with regard to the method by the characteristics of the

Claim 1, with respect to the device by the features of the claim 30 Advantageous refinements and developments result in each case from the dependent claims.

The method for testing the stability and / or bending strength of masts, in particular masts not braced, according to claim 1 provides: a) that the test is carried out dynamically, b) the mast being moved, in particular by artificially generated force Vibrations, is excited, and c) the movements of the mast are determined by one or more sensors arranged on the mast, in particular accelerometers, which record measured values at their respective positions on the mast.

The advantages achieved by the invention are, in particular, that not only static values are available for the evaluation, but also, in addition, above all, the dynamic behavior of the mast is also recorded and can thus be evaluated. This makes it much easier to simulate the real load caused by natural forces, especially wind forces. The known evaluation based on a force-displacement characteristic curve can, however, also be carried out in this method, since the path can be determined by double integration of the measured or Let acceleration values be determined.

Furthermore, in the dynamic method according to the invention, sufficient results can be obtained with significantly lower forces than with the static λ ^ experiences, so that the risk of overloading the mast and thus the possibility of damage to the mast given in the prior art due to the large forces required Mastes through the test is not given.

Under dynamic testing is the detection of the dynamic behavior of the mast when excited by a force, i.e. to understand the movement behavior of the mast. Accordingly, the sensors are not used, as in the prior art, but are preferably used with accelerometers.

Commercially available devices come into consideration as accelerometers (or: accelerometers). These work, for example, according to the spring-mass principle, with micromechanical methods and capacitive analysis, with magnetic field sensors, with pressure sensors or with piezoelectricity. Artificially generated force, in contrast to natural wind power, is to be understood as a targeted force effect, usually by means of a suitable device, which acts on a mast. As a result, the test is not dependent on random, naturally occurring forces, but can be reproduced be carried out by appropriate regulation of the artificially generated force on the basis of a predetermined or predefinable test plan. This also means that not all measurements have to be carried out in parallel, but because of the reproducibility of the forces it is also possible to measure parameters one after the other, the measured values subsequently being able to be correlated with one another.

The mast movements are expediently stimulated by a force which changes over time, in space or in their direction and / or in their amount.

It proves to be advantageous if the mast movements are excited by a periodic force that changes in their direction and / or in their amount. It is useful if the excitation frequency of the force is adjustable, especially continuously. In particular, the adjustability should also include the generation of fundamental waves (or: natural frequencies) and, if necessary, also harmonics of a mast to be tested, thus enabling resonance excitation. This can also be done automatically adaptively.

According to a further development, the force which stimulates the mast movements can also be a force pulse and / or a force pulse sequence. A force impulse is a short-term force impulse that immediately drops back to zero or a smaller value. This can simulate gusts of wind.

The force expediently lies essentially in a plane perpendicular to a longitudinal axis (or: longitudinal central axis, longitudinal axis of the mast, mast axis) of the mast, in particular it is directed radially to a longitudinal axis of the mast. The artificial force attacks like the natural wind power on the side of the mast.

According to a preferred embodiment of the method, the force runs circularly about a longitudinal axis of the mast, in particular periodically and / or with a constant amount of force over time. Such a force causes a mast movement that rotates around the longitudinal axis in the idle state. Alternatively, the direction of force on a straight line perpendicular to one

Longitudinal axis of the mast lie and the force rector change over time. The mast deflection then takes place in a plane parallel to the longitudinal axis of the mast in the idle state, which also contains the longitudinal axis of the mast in the idle state.

It may also be expedient for the force to act on the mast in a torsional manner, in particular at least tangentially on a side or jacket surface of the mast with respect to a force component. Daduich the mast is twisted in itself about its longitudinal axis. It is also possible for a force to have both a radial and a tangential and thus torsionally acting component.

The force acting on the mast is preferably generated by a device which is arranged on the mast, in particular in the upper third of the mast height and / or on an outside, preferably an outer side or jacket surface of the mast. Attaching the device in the upper third ensures that the artificially generated force engages in this area and thus, due to the distance to the anchored mast base - compared to an attachment in the lower mast area - for the greatest possible reaction of the mast to the exciting force. The attachment on the outside or in the case of round or oval masts on the surface of the jacket makes sense, since this means that the device does not have to be laboriously inserted into the interior of the mast, which would only be possible with appropriately trained masts.

It has proven to be particularly advantageous to use an unbalance exciter as a device for generating force. It is expedient to use an unbalance exciter whose unbalance, which generates the desired forces with appropriate movement, is essentially based on at least one mass. Even two or more masses are preferred. These masses are generated during the operation of the unbalance exciter, i.e. to generate the forces.

It is particularly advantageous if the mass or the masses of the unbalance exciter is or are moved about the longitudinal axis of the mast and / or about the mast. In particular, the masses should be moved radially outside an outside or - in the case of round or oval masts - a lateral surface of the mast. The masses should therefore circle the mast, i.e. preferably move in a circle around the mast, in a plane perpendicular to the longitudinal axis of the mast.

It is also preferred that the mass or the masses is driven by one or more linear drives, in particular one or more linear motors respectively. A linear motor is composed of individual elements (linear or excitation windings) which, with an appropriate arrangement, can also produce a circular movement of the masses around the mast. For example, such a linear motor 256 can have elements arranged in a ring. The mass or masses form, among other things, the rotor of the linear motor.

The spacing between linear winding and rotor is done b e Preferred by electromagnetic levitation, ie the mass or masses levitate electromagnetically controlled. This means that you have no direct contact with other components during operation, so the friction losses are low.

In an alternative embodiment, the runner can also be guided mechanically.

The required or desired forces can be generated, for example, by an unbalance exciter in which two masses rotate in a circular or elliptical shape. With an appropriate arrangement of this imbalance exciter on the mast, both masses run in a circular or elliptical shape around the mast or the longitudinal axis of the mast. Such an imbalance exciter can be implemented by two drives, one of the masses circulating in each drive. The two linear drives are expediently arranged one above the other so that the radii of the orbits of the masses correspond to one another. In this case, the two masses should correspond to one another, that is to say, among other things, have the same weight and the same shape. The effect of an elliptically rotating mass can also be achieved by a two-part mass rotating on a circular path consisting of a basic mass and a trimming mass, if the distance between the basic mass and the trimming mass is periodically changed - coordinated with the circulating frequency on the circular path.

Are both masses, which may each include two basic and

Trimming mass can be designed, controlled in such a way that they move in opposite directions around the mast, and at the same speed on paths corresponding radially around the mast axis, this leads to a linear force effect on the mast, i.e. the force is always in one Level parallel to the long axis of the mast. This results from the fact that each mass produces a radially rotating force. The vector addition of the forces emanating from both oppositely rotating masses results in a variable linear force, ie a force in which changes periodically with the mass rotation frequency a plane parallel to the mast axis. Accordingly, the mast is excited to a linear deflection movement, ie the mast deflection takes place in a plane parallel to the longitudinal axis of the mast in the idle state, which also contains the longitudinal axis of the mast in the idle state. The radial "meeting points" of the revolving masses also lie in this plane. Since the masses revolve axially along the mast axis relative to one another around the mast, these "meeting points" are the crossing points of the mass trajectories which result from an axial projection onto one another.

These crossing points can be determined by varying the phase control of the drives, so that a desired vibration level can be set electrically / electronically. There is no time-consuming mechanical twisting of the device.

A circular mast deflection movement (in contrast to the linear deflection movement here, the mast revolves around the mast axis in the idle state) can be achieved with such a device with two masses, for example, by a synchronous, i.e. unidirectional orbital movement, cause both masses, in particular by masses rotating in parallel to each other.

A torsional force acting on the mast can be generated by braking and / or accelerating the masses, whereby this can be achieved equally with an unbalance exciter with one mass, with two masses or with several masses by appropriate mass control.

According to an expedient embodiment of the method, the measured or acceleration values recorded are horizontal

Acceleration values, which are determined essentially in a plane perpendicular to a longitudinal axis of the mast, in particular by means of motion sensors arranged on the mast and oriented to record lateral movements, i.e. horizontal motion sensors. Additively or alternatively, vertical acceleration values can also be recorded, which are determined essentially parallel to a longitudinal axis of the mast, in particular by means of acceleration sensors arranged on the mast and oriented to record longitudinal movements, i.e. vertical motion sensors.

According to a further development, horizontal acceleration values are determined in one or more measurement planes distributed over the mast height, in particular in three measurement planes, with a first measurement plane preferably in the lower third of the Mast height and a 7 \\ eite measurement level in the middle third of the mast height and a third measurement level in the top third of the mast height.

The acceleration values can be determined in parallel in different measurement levels by arranging a corresponding number of acceleration sensors. Alternatively, it is also possible to measure or

To determine the acceleration values of different measurement planes one after the other, for example by moving a robot with acceleration sensors that can be moved along the mast (in particular self-propelled) one after the other into the respective measurement plane on the mast. The robot preferably controls the respective measurement levels in a self-controlled manner or automatically controlled by a control device. The prerequisite for this, however, is that there are no obstacles on the mast, for example signs attached or lines laid on the outside of the mast. Obstacles may need to be removed. Alternatively, the method can also be carried out using a cable suspension.

According to a further method variant, two or more, preferably four, measurement or acceleration values are determined in at least one measurement level, in particular in the uppermost measurement level, the measurement points being distributed uniformly in the measurement level on the mast. This means that four measured values in one plane are arranged perpendicular to each other with respect to the longitudinal axis of the mast. The measurement or acceleration values of a measurement level can be determined by a corresponding number of acceleration recorders, i.e. With four measured values, four accelerometers, which are arranged perpendicular to each other with respect to the longitudinal axis of the mast, are determined in parallel. However, the measurement or acceleration values of a measurement plane can also be determined one after the other, for example by arranging a robot with one or more acceleration sensors on the mast, the robot or the

Accelerometers can rotate around the longitudinal axis of the mast to take up the various measuring positions within a measuring plane. This robot and the aforementioned robot that can be moved along the mast can be a device.

A further process development provides that one or more vertical measuring or Acceleration values, in particular two vertical acceleration values, are determined on or near a mast base. Mast foot is the long end of the mast anchored (usually in a foundation). The accelerometers are used to determine two vertical acceleration values preferably anoid on two opposite sides of the mast on or near the base of the mast.

The method according to the invention provides acceleration values and thus dynamic measurement quantities for evaluations by comparing these measurement quantities or values calculated therefrom, for example for different measurement levels and / or deflection directions, and / or by comparison with reference values, for example theoretically calculated values or values From previous measurements, conclusions can be drawn about the stability or bending strength of the mast. In particular, the following characteristic values of the mast can be checked: tilting the foundation, bending the mast via the height and torsional load.

In a further development, the method provides for evaluation that a) the mast deflection in the respective measurement planes is calculated by double integration of the determined horizontal acceleration values and from this a measured (i.e. actual) bending line of the mast is determined, b) the measured bending line with a sample Bend line, in particular a bending line theoretically determined taking into account stimulating force and / or mast cross section and / or mast material is compared, and c) deviations between measured and sample bend line are determined.

In determining the pattern Biegehnie can additionally or alternatively also of the _S) stemeigenschaften of the mast in the new state (baseline measurement) can be assumed.

In a further step, discrepancies between the measured and calculated bend line can then be used to identify quality defects in the mast, in particular material defects and / or inclusions and / or breaks. This enables the bending strength of the mast to be determined and assessed. Recognizable non-linearities in bending behavior are particularly critical.

For evaluation, the mast deflection in the respective measuring planes can also be calculated by double integration of the determined horizontal acceleration values and a force-deflection characteristic can be established from this, from its course, in particular from recognizable non-linear elements, poor quality of the mast, in particular material defects and / or inclusions and / or breaks An evaluation as in the prior art described above (static methods) is thus also possible with the dynamic method according to the invention.

A further development of the method provides that a) mast deflections in different directions are determined by double integration of a plurality of horizontal acceleration values that were determined in one measurement plane, and b) from differences in these deflections, in particular with regard to the amount of the maximum deflection, Poor quality of the mast, in particular cross-sectional deformations and / or twisting of the mast, can be detected.

After an advantageous further evaluation step, a) is to be determined by double integration of the determined vertical acceleration values, in particular from two on opposite mast sides

Acceleration values, the movement of the respective measuring points are determined and b) a tilting of the mast in its anchoring (foundation) is determined from these movements and the distance between the measuring points.

This enables the stability of the mast to be determined and assessed.

An expedient and advantageous further development provides that the frequency response, the damping coefficient, in particular from the maximum, from the movement of the mast stimulated by the force at different excitation frequencies

Deflection of the mast at different excitation frequencies, the natural frequency of the mast is determined. The maximum deflection at a specific excitation frequency can in each case be determined by double integration of the acceleration values determined.

According to claim 30, the device for testing the stability and / or bending strength of masts, in particular masts not braced, preferably by means of a dynamic method described above, a) an unbalance exciter which generates a force acting on the mast to be tested, in particular a periodic force on which the mast is arranged or can be arranged, especially in the upper third of the mast height, b) one or more accelerometers used to detect

Acceleration values are arranged or can be arranged on the mast, and c) an evaluation device for determining the stability and / or bending strength of the mast to be tested and / or quality defects of the mast to be tested

The advantages of this device result from the above explanations of the method

The unbalance of the unbalance exciter is preferably based essentially on at least one mass, preferably on two or more masses. This mass or the masses is or are moved during operation of the unbalance exciter.

According to a further development, the mass or the λlass are moved in a circle around the longitudinal axis of the mast, in particular outside the mast, preferably radially outside a side or jacket surface of the mast.

The mass or the masses is expediently driven by a linear drive, in particular a linear motor, which is composed, for example, of 256 elements (excitation coils), in particular in a ring. It is also advantageous if the λ class or the masses hover or hover electromagnetically controlled during operation of the unbalance exciter, i.e. have no contact with other components during operation.

Especially for the method variants mentioned above, which provide a method of accelerometers in different measuring positions, the device should position at least one robot for positioning the

Accelerometers and / or the unbalance exciter on the mast to be tested, where the robot comprises two or more components which are connected or can be placed in a ring around the mast to be tested, and at least one device for attaching accelerometers and / or unbalance exciters. At least one component connection can be a hinge

Suitably w pus, w the Robotei hen a mechanism for λ ⁷ out of the robot along the mast umfas st, preferably a mechanism with driven wheels, which in the method the pole bear The Anbungung of the wheels should be thereby flexibly, so that the robot It can also be used on masts with different Duich knives. Flexible wheel suspension also allows the robot to be driven along a mast along the mast Mast axis changing mast diameter. This can be achieved with a sprung

Wheel suspension or a correspondingly controllable wheel suspension, in which the control system always ensures that the wheels are firmly attached to the mast.

A further development of the device is expedient, in which the robot has a mechanism for rotating the device for attaching

Accelerometers around the longitudinal axis of the mast. This means that the accelerometers can be automatically moved to different measuring positions within one measuring plane.

The invention is further explained below using exemplary embodiments and with reference to the accompanying drawings. Show it

1 shows an exemplary embodiment of a device according to the invention, arranged on a mast to be tested,

2 schematically shows a cross section with respect to the longitudinal axis of another mast

Exemplary embodiment of a device according to the invention, arranged on a mast to be tested,

3 shows an exemplary embodiment of a robot of a device according to the

Invention in a state not attached to the mast, and

4 shows the robot according to FIG. 3 in a state attached to the mast.

Parts corresponding to one another and are provided with the same reference symbols in FIGS. 1 to 4.

1 shows an exemplary embodiment of a device 10 for testing the stability and / or bending strength of masts according to the invention, arranged on a mast 1 1 to be tested. This device 10 is set up and intended for the method according to the invention for testing the stability and / or to carry out the bending strength of the mast 1 1.

The mast 11 is an elongated object with a mast (slow) axis 19. In FIG. 1, the diameter of the mast 11 is constant over its entire length, but a mast with a diameter that changes along the mast length can also be considered. The mast 1 1 has a mast tip 15 at one long end and a mast foot 16 at one of the long ends opposite the mast tip 15. The mast 1 1 is anchored to mast foot 1 6 in a foundation 1 7 in the ground 1 8% and rises vertically above the ground 18 into the height Ensure sufficient stability of the mast 1 1 The height of the mast tip 1 5 above the floor 1 8 is referred to as the mast height h. The mast can be made of wood, metal, concrete and / or plastic, for example. It can be hollow on the inside, for example for carrying it through of lines, but it can also be designed without a cavity. The diameter of the mast can be round or oval, but other cross-sectional shapes are also possible, for example square or rectangular cross-sections or T-shaped or U-shaped cross-sections. Outwardly, the mast 11 is laterally delimited by a side or jacket surface 20

Through the procedure according to the invention, the stability of the master 1 1, i.e. in particular the strength of the anchorage in the floor 1 8, and the bending strength of the mast 1 1, i.e. its elasticity or stability against damage under load are checked.

For this purpose, the arrangement of various components of the device 10 is shown in FIG. 1 in a stylized form. As shown schematically in FIG. 1, the device 10 comprises an unbalance exciter 12 which is intended to generate a force acting on the mast 11 to be tested, in particular a periodic force. The unbalance exciter 12 is arranged in the upper third of the mast height h on the mast 11.

According to a first variant, the unbalance of the unbalance exciter 12 is based on a mass (not shown). This mass encircles the mast 11 during operation of the unbalance exciter 12 within the unbalance exciter 12, ie the mass runs in a circle (or elliptical) around the mast axis 19, radially outside the side or lateral surface 20 of the mast 11. This leads to a circular (or elhps-shaped) movement of the mast 1 1 about the mast axis 19 in the idle state of the mast 1 1, that is. the rotating mass initially exerts a radial force on the mast 1 1, which leads to a mast deflection, and further this deflection force circles due to the rotating mass around the mas axis, so that there is a total of the circular deflection movement of the mast 1 1. The mast 1 1 is thus stimulated by the artificially generated force which emanates from the unbalance of the balancer 1 2, in connection with its inherent forces, to movements, in particular vibrations, the detection of which represents the core of the test procedure. The movement of the masses is carried out by a linear motor (not shown), the individual elements (linear or excitation windings) of which are angularly shaped in the unbalance exciter 12 in order to enable a circular or elbow-shaped movement 7U. For example, 256 elements can be used here. The mass hovers during operation of the imbalance exciter 12, controlled electromagnetically within the imbalance exciter 1 2, in particular within the individual elements.

According to a second, preferred variant, the unbalance of the unbalance exciter 12 is essentially based on two corresponding, i.e. Units of the same shape and made of the same materials (masses, not shown). These masses orbit the mast 1 1 during operation of the unbalance exciter 1 2 within the unbalance exciter 1 2, i.e. the masses run in a circle (or ellipse) around the mast axis 19, radially outside the side or lateral surface 20 of the mast 11. The planes of movement of the two masses are axially offset from one another along the mast axis 19, but have essentially the same radial distance from the mast axis. With a parallel movement of the masses, as with only one mass, this leads to a circular movement of the mast 11 around the mast axis 19 in the idle state of the mast 11. If the masses move in opposite directions, however, there is a linear movement of the mast 11, i.e. the mast swings in a plane parallel to the mast axis 19 in the idle state. The mast 1 1 can thus be artificially through this

Imbalance exciter 1 2 also generate force to produce linear movements, in particular vibrations.

In the second variant, too, the mass is moved by linear motors (not shown), in this case, however, by two linear motors, for each mass one. The linear motors are arranged in the balancing exciter in such a way that, when in operation, they lie one above the other on the mast (in relation to the mast axis). The individual elements (linear or excitation windings) of each imbalance exciter are in turn arranged in a circular or elliptical shape in the imbalance exciter 12 in order to enable a circular or elliptical movement of the masses.

With both variants of the unbalance exciter, a force acting torsionally on the mast can be generated by the mass or masses being braked and / or accelerated in a suitable manner by the linear motors.

The device 10 also includes mehiere accelerometers 1 3, 14 for detecting acceleration values of the mast 1 1. These are distributed over the mast height on the mast 1 1. Specifically, this sits along a line parallel to the Mast axis 1 9 at least two horizontal acceleration transducers 1 3 in the bottom third, in the middle third and in the top third (near the top of the mast 1 5) of the mast height h of the masts 1 1. In a plane perpendicular to the mast axis 1 9, two further horizontal acceleration transducers 1 3 are arranged at a height of the uppermost horizontal acceleration transducer 1 3, each offset by 90 ° to one another on the side or jacket surface (in FI G 1 an accelerometer concealed on the mas truck side). The term “horizontal acceleration sensor” is to be understood here to mean that these acceleration sensors 1 3 are arranged on the mast 11 in such a way that they detect an acceleration of the mast 11 in the (essentially) horizontal direction.

On the mast base 16 are also arranged opposite one another on the side or jacket surface 20 of the mast 11, three, preferably four, vertical accelerometers 14, each offset by 90 °, which (essentially) vertical movement of the mast 11, i.e. a movement (essentially) parallel to the mast axis 1 9.

Finally, the device 10 also includes an evaluation device 21, which is shown symbolically in FIG. The control device of the entire device 10 can also be assigned to the evaluation device 21, so that it is then a control and evaluation device 21. An evaluation of the test on site can also be dispensed with, so that in this case it is merely a recording device 21 for the measured values or. is a control and detection device 21.

The individual components of the device can be connected to each other for the transmission of control commands and / or measured values, in particular, but radio transmission is also possible. The energy supply of the individual components can in each case be carried out autonomously via batteries or accumulators or via cable connections from a central energy source.

The device 10 can be used to carry out the method according to the invention for checking the stability and / or bending strength of masts 11, in particular masts 11 which are not braced.

For this purpose, the mast 11 in the top third of the mast height h is excited to vibrate by the unbalance of the unbalance exciter 12. The horizontal accelerometers 1 3 determine the acceleration values c (acceleration signals) at their respective positions (measuring points) on the mast 1 1 and pass them on to the recording and / or evaluation device 21 for recording and / or evaluation.

With regard to the evaluation, the deflection of the mast in the various planes can be calculated, for example, by double integration of the acceleration signals and thus a measured bending angle of the mast 11 can be determined. By the

Comparison of these measured bending knees with a bending knee calculated in particular for the applied load (ie the force exerted on the mast 1 1 by the unbalance exciter 12), the special cross section of the mast 1 1 and the mast material can be concluded on the material quality of the mast 1 1 and material defects, inclusions and breaks can be identified.

If the evaluation of the determined values yields critical or uncertain results for a specific deflection direction of the mast 11, the device 10 enables a further targeted and possibly also more detailed examination of this deflection direction by appropriately arranging the acceleration sensors 13 (possibly also 14).

The arrangement of four accelerometers 13 in one plane in the top third of the mast height h likewise provides information about deflections of the mast 1 1 through double integration, which can differ not only in their direction but also in their amount. This evaluation enables conclusions to be drawn about cross-sectional deformations and twisting of the mast, which can be documented in this way and evaluated in particular using material parameters.

The measured values of the arrangement of the four vertical accelerometers 14 on two opposite sides of the mast base enable the tilting of the foundation 17 to be determined by calculating the paths (again by double integration) and taking into account the distance between the vertical accelerometers 1 4. This reduces the probability of a tipping over of the mast 1 1, ie the stability of the mast 1 1.

Finally through the rotational speed of the unbalance (the mass), the ficence response, the damping coefficient and the maximum deflection of the mast 11 and thus the natural frequency of the mast 11 are determined. This frequency represents the critical case of wind excitation. The wind excitation must not excite this natural frequency of the mast 1 1, the (determined) natural frequency of the mast 1 1 must therefore be outside a critical one Frequency range. Otherwise, adaptation measures to change the natural frequency of the mast may be necessary.

The test method described has the advantage that the course of the bending lines in the elastic range of the material is proportional to the load and can therefore be worked with small unbalances and therefore with low forces during excitation. There is therefore no risk of overloading the mast, so that the likelihood of the mast being damaged by the test is low, in any case significantly less than in the case of the methods known from the prior art and explained at the outset, which require mast loading that clearly is above the expected maximum natural wind load.

The device described is particularly suitable for round and / or oval masts with a diameter of at most 50 cm, in particular of at most 30 cm.

2 schematically shows a further exemplary embodiment of an unbalance exciter 1 2 in cross section with respect to the longitudinal axis of the mast, arranged on a mast 11 to be tested. In this exemplary embodiment, the mass of the unbalance exciter 12 comprises a base mass 28 and a trim mass 29, the relevant radial distance δ in the projection being able to be set on a plane perpendicular to the longitudinal axis of the mast between base mass 28 and trim mass 29 by means of a distance adjustment component 30. This ensures that a force adapted for the test procedure can be set by a user or changed during the test procedure.

The base mass 28 moves in the presently shown guide form from a circular path 31. At the same time, it is possible to change the distance δ of the trimming mass 29 to the base mass 28 so that it matches the circulating frequency of the base mass 28 in such a way that, despite the circular orbit of the base mass 28, there is an elliptically distributed action of force, i.e. the effect of a single mass circulating on an elliptical path is achieved.

FI G 3 shows an exemplary embodiment from a robot 22 of a device 10 according to the invention, specifically in a state not attached to a mast 11, ie before or after an attachment to the mast 11. 4 shows this robot 22 in a state attached to the mast 11. The comparison of FIG. 3 and FIG. 4 shows that the robot 22 consists of several components which are connected to one another for attachment to the mast 11 and for removing the robot 22 from the Mast 1 1 can be separated from each other again. You can also do this

Hinge connections may be provided so that the individual components of the robot 22 are connected to one another even when removed.

The robot 22 comprises a base frame 23 which, in a state attached to a mast 11, has an annular shape and thus surrounds the mast 11 in a ring shape. A plurality of wheels 24 are attached to the base frame 23 via suspensions 25. The wheels 24 lie (in the attached state of the robot 22) on a circle around the mast axis. The position of the wheels can be adjusted via their suspensions 25, so that the radius of the circular arrangement of the wheels 24 can be adjusted. As a result, the robot 22 can be adapted to different mast diameters.

In the attached state (FIG. 4), the positions of the wheels 24 are set such that the wheels 24 rest on the mast 11. The surface of the wheels 24 has a high level of friction, by means of which the robot is held on the mast 11 while driving. The locking in the measuring position is carried out by locking means, in particular locking spindles, preferably 3. The locking means bring about an undamped coupling of the locking forces.

The wheels can be rotated via a drive 26, so that the robot 22 can be moved up and down along the mast, in a self-driving manner. If necessary, an adaptation to a changing mast diameter can take place via the suspension 25.

Measuring devices, for example, can be located on the robot 22

Accelerometers are attached. These can then be moved into the desired measurement planes by the robot 22. Attaching an imbalance exciter to the robot 22 is also possible.

Overall, a method and a device for checking the

Strength of masts, in particular masts not braced, proposed with which the following characteristic values of a mast can be checked in particular: tilting of the foundation, bending of the mast via the high and torsional load, frequency response, resonance coefficient and resonance frequency. Reference sign list

1 0 device

1 1 mast

1 2 unbalance exciters

1 3 horizontal accelerometers

1 4 vertical accelerometers

1 5 mast tip

1 6 mast base

1 7 foundation

1 8 floor

1 9 mast (slow) axis

20 side or jacket surface

21 evaluation and / or control and / or recording devices

22 robots

23 base frame

24 wheels

25 suspension

26 drive

27 locking means

28 base mass

29 trim

30 Distance control component

31 circular path

h Mast height δ distance between base mass and trim mass

Claims

1 . Method for testing the still and / or bending strength of masts (1: 1), in particular not guyed tower (1 1), a) wherein the assessment d _j carried cally, b) the mast (1: 1) by an artificially generated Force to movements, in particular vibrations, is stimulated, and c) the movements of the mast (11) being measured or accelerated by one or more sensors, in particular acceleration sensors (13, 14) arranged on the mast (11) their respective position on the mast (1 1), determined.

2. λ ^ experience according to one of the preceding claims, in which the mast movements are excited by a force which changes over time in their direction and / or their magnitude.

3. The method according to any one of the preceding claims, in which the mast movements are excited by a periodically changing force in their direction and / or their amount.

4. The method according to claim 3, wherein the excitation frequency of the force is adjustable, in particular continuously.

5. The method according to any one of the preceding claims, wherein the force stimulating the mast movements is a force pulse and / or a force pulse sequence.

6. λ ^ experience according to one of the preceding claims, in which the force is substantially in a plane perpendicular to a longitudinal axis (19) of the mast (1 1), in particular directed radially to a longitudinal axis (19) of the mast (1 1) is.

7. The method according to any one of the preceding claims, wherein the force circulates in a circular or elliptical manner about a longitudinal axis (19) of the mast (1 1), in particular periodically and / or with a constant amount of force.

Method according to one of claims 1 to 6, in which the direction of force is constant on a straight line and is perpendicular to a longitudinal axis of the mast (19) and the force vector changes over time.

9. The method according to any one of the preceding claims, in which the force acts torsionally on the mast (1 1), in particular at least with regard to one

Force component acts tangentially on a side or jacket surface (20) of the mast.

10. The method according to any one of the preceding claims, wherein the force acting on the mast (1 1) is generated by a device (12) which on

Mast (10) is arranged, in particular in the upper third of the mast height (h) and / or on an outside, preferably an outer side or jacket surface (20) of the mast (1 1).

1 1. The method of claim 10, wherein the device is an unbalance exciter (12).

12. The method of claim 1 1, wherein the unbalance of the unbalance exciter (12) is based essentially on at least one mass, preferably on two or more masses, and this mass or masses during operation of the

Unbalance exciter (12) are moved.

13. The method according to claim 12, in which the mass or the masses about the longitudinal axis of the mast (19) and / or the mast (1 1) is or are moved, in particular radially outside of an outside or lateral surface (20) of the

Mastes (1 1) and / or preferably circular.

14. The method according to claim 12 or 13, wherein the mass or the masses is driven by one or more linear drives, in particular one or more linear motors.

15. The method according to any one of claims 12 to 14, wherein the mass or the masses levitates electromagnetically regulated or levitates or is mechanically felt b7 \ v. are.

1 6. Method according to one of the preceding claims, in which the measured values recorded are preferably horizontal acceleration values, which are essentially determined in a plane perpendicular to a longitudinal axis of the mast (19), and / or vertical acceleration values, which are in the Can be determined essentially parallel to a longitudinal axis of the mast (19).

17. The method according to claim 16, in which horizontal acceleration values are determined in one or more measuring planes distributed over the mast height (h), in particular in three measuring planes, preferably one ice measuring plane in the lower third of the mast height (h) and a second measuring plane in the middle Third of the mast height (h) and a third measuring level in the top

Third of the mast height (h).

1 8. The method according to claim 17, in which acceleration values are determined in parallel in different measurement planes by arranging a corresponding number of acceleration sensors (13, 14).

19. The method as claimed in claim 17, in which acceleration values of different measurement planes are determined one after the other, in particular by moving a robot (22) with acceleration sensors which can be moved along the mast (11) in succession into the respective measurement plane on the mast (11)

20. erfahren ^ experience according to one of claims 16 to 19, in which two or more, preferably four, acceleration values are determined in at least one measuring plane, in particular in the uppermost measuring plane, the measuring points being uniform in the measuring plane on the mast (1 1) are distributed.

21st Method according to Claim 20, in which the acceleration values of a measuring plane are determined in parallel by a corresponding number of acceleration sensors (13, 14).

22. The method according to claim 20, in which the acceleration values of a measurement plane are determined one after the other, in particular by arranging a robot (22) with one or more acceleration sensors on the mast, which can rotate the acceleration sensor or accelerometers about the longitudinal axis of the mast to take the various measurement positions within one

Measurement level.

23. The method according to any one of the preceding claims, in which one or more vertical acceleration values, in particular two vertical acceleration values, are determined at or near a mast base (1 6).

24. The method according to any one of the preceding claims and claim 16, in which a) the mast deflection is calculated in the respective measurement planes by double integration of the determined horizontal acceleration values and from this a measured bending angle of the mast (11) is determined, b) the measured bending angle a sample Biegelmie, especially one under

Consideration of stimulating force and / or mast cross section and / or

Mast material theoretically determined bending line or a zero measurement is compared, and c) deviations between the measured and sample bending line, in particular theoretically determined bending line or zero measurement, are determined.

25. λ ^ experience according to claim 24, in which from detected deviations between the measured and calculated bending angle, the poor quality of the mast (11), in particular material defects and / or inclusions and / or breaks, is recognized.

26. The method as claimed in one of the preceding claims and claim 16, in which the mast deflection in the respective measurement planes is calculated by double integration of the determined horizontal acceleration values, and a force-deflection characteristic is established from the latter, from the course of which the poor quality of the mast (11) , in particular material errors and / or inclusions and / or breaks, can be detected.

27. The method according to any one of the preceding claims and according to claim 20,

a) by double integration of several horizontal acceleration values, which were determined in one measuring plane, mast deflections in different directions are determined, and b) from differences of these deflections, in particular with regard to the amount of the maximum deflection, poor quality of the mast (1 1), in particular

Cross-sectional deformations and / or twists of the mast (1 1) can be detected

28. Procedure according to one of the preceding claims and according to claim 23,

a) the movement of the respective measuring points is determined by double integration of the determined vertical acceleration values, in particular two acceleration values determined on opposite mast sides, and b) a tilting of the mast from these movements and the distance between the measuring points (1 1 ) is determined in its anchoring.

29. The method according to any one of the preceding claims and according to claim 4, in which from the movement of the mast (1 1) excited by the force at different excitation frequencies, in particular from the maximum deflection of the mast (1 1) at different excitation frequencies, the frequency response which The damping coefficient and / or the natural frequency of the mast (1 1) is determined.

30. Device (10) for checking the stability and / or bending strength of masts (1 1), in particular masts not braced (H), preferably by means of a dynamic method according to one of the preceding claims, comprising a) an unbalance exciter (12), the force acting on the mast to be tested (1 1), in particular a periodic force, is arranged or can be arranged on the mast (1 1), in particular in the upper third of the mast height (h), b) one or more accelerometers ( 13, 14), which are arranged or can be arranged to record acceleration values on the mast (11), and c) an evaluation device (21) for determining the standing and / or

Flexural strength of the mast to be tested (1 1) and / or of poor quality of the mast to be tested (1 1)

31 Apparatus according to claim 30, wherein the imbalance of the imbalance exciter (12) is based essentially on at least one mass, preferably on two or more masses, and this mass or masses is or are moved during operation of the imbalance exciter (12).

2 Device according to claim 31, in which the mass or the masses is or are moved circularly around the longitudinal axis of the mast (19). v

33. Apparatus according to claim 31 or 32, in which the mass or masses is or are driven by a linear drive, in particular a linear motor.

34. Device according to one of claims 31 to 33, in which the mass or masses during operation of the unbalance exciter (12) floats or float in an electromagnetically controlled manner or is guided mechanically.

35. Device according to one of claims 30 to 35, designed and intended for carrying out the method according to claim 19 and / or claim 22, comprising at least one robot (22) for positioning the acceleration sensors (13, 14) and / or the unbalance exciter (12 ) on the mast to be tested (1 1), wherein the robot has two or more components which are connected or can be placed in a ring around the mast (1 1) to be tested, and at least one device for attaching accelerometers (13, 14) and / or unbalance exciter (12).

36. Apparatus according to claim 35, wherein the robot (22) comprises a mechanism for moving the robot (22) along the mast, preferably a mechanism with driven wheels (24) which bear against the mast (11) during the movement.

37. Device according to claim 35 or 36, wherein the robot (22) comprises a mechanism for rotating the device for attaching accelerometers (13, 14) and / or unbalance exciter (12) about the longitudinal axis of the mast (19).