METHOD AND TEST DEVICE FOR SIMULTANEOUSLY TESTING TWO ROTOR BLADES AND / OR TWO ROTOR BLADE SEGMENTS FOR A WIND ENERGY PLANT

Description

[0001] The invention relates to a test device for simultaneously testing two rotor blades and / or two rotor blade segments for a wind turbine, a method for simultaneously testing two rotor blades and / or two rotor blade segments for a wind turbine, a method for testing one rotor blade and / or one rotor blade segment for a wind turbine, and the use of a test device for testing one rotor blade and / or one rotor blade segment for a wind turbine and / or for simultaneously testing two rotor blades and / or two rotor blade segments for a wind turbine.

[0002] The trend towards ever larger wind turbines with increasing rated power also leads to ever larger and longer rotor blades. With increasing size and length, the rotor blades of larger wind turbines are also subjected to greater static and dynamic loads.

[0003] In the development of rotor blades for wind turbines, in addition to modeling the rotor blades, tests are often required that include both static (extreme) load tests and tests with cyclic or dynamic fatigue loads. The rotor blades are typically tested on test rigs to determine whether their fatigue strength and / or other properties are sufficient for the intended service life. In particular, rotor blade testing serves to verify that the materials used in the blade and their connections are safe, reliable, and load-bearing (e.g., whether the (fiber) layers used to manufacture a blade do not separate (i.e., no delamination occurs) or whether the spar caps are sufficiently load-bearing) and / or whether the blade does not break under repeated and / or extreme loading.

[0004] These tests, conducted before deployment and especially before rotor blades reach series production, can significantly delay and increase the cost of implementing a new rotor blade design. A further challenge is that the test equipment is also expensive to purchase and operate, which further increases the cost of rotor blades and wind turbines. In particular, currently available test rigs are not suitable for testing rotor blades longer than 70 m, 80 m, 90 m, or 100 m. Expanding existing test rigs to accommodate rotor blades longer than 70 m, 80 m, 90 m, or 100 m would—if even feasible—result in extremely high investment costs, jeopardizing the economic viability of such projects.US 8,677,827 B2 describes multi-axis degrees-of-freedom blade testing systems that utilize base excitation to enable more efficient fatigue testing of wind turbine blades. However, further improvements are desirable.

[0005] The German Patent and Trademark Office has searched the following prior art in the priority application for the present application: DE 10 2016 117 647 A1, DE 10 2018 218 515 A1, US 8 677 827 B2.

[0006] The European Patent Office has searched the following prior art for the present application: US 2020 / 132052 A1, US 8 578 753 B2, EP 3 296 715 B1 and DE 654 009 C. In particular, EP 3 296 715 B1 discloses a device and a method for obtaining data on a rotor blade for a wind turbine.

[0007] It is therefore an object of the present invention to reduce or eliminate existing disadvantages and / or to provide an improved solution and / or a solution for a wider range of applications, in particular for rotor blades with a length of over 70 m, over 80 m, over 90 m or over 100 m.It is particularly an object of the present invention to provide an improved test device for the simultaneous testing of two rotor blades and / or two rotor blade segments for a wind turbine, an improved method for the simultaneous testing of two rotor blades and / or two rotor blade segments for a wind turbine, an improved method for testing one rotor blade and / or one rotor blade segment for a wind turbine, and the use of a test device for testing one rotor blade and / or one rotor blade segment for a wind turbine and / or for the simultaneous testing of two rotor blades and / or two rotor blade segments for a wind turbine.

[0008] This problem is solved according to the invention by a test device for simultaneously testing two rotor blades and / or two rotor blade segments for a wind turbine, comprising a first adapter element for attaching a first rotor blade or rotor blade segment thereon, a second adapter element for attaching a second rotor blade or rotor blade segment thereon, a support structure to which the first and second adapter elements are attached, and an excitation device configured to apply a static and / or cyclic load to the first and / or second rotor blade or rotor blade segment, wherein the first and second adapter elements are connected to each other.

[0009] As will be described below, the supporting structure is preferably arranged on a foundation, which can also be referred to as a test platform.

[0010] The two rotor blades and / or rotor blade segments are attached to two adapter elements, which in turn are connected to each other and to the supporting structure, in particular by means of hinges. This test device thus makes it possible to attach two rotor blades and / or rotor blade segments to each other, in particular via a connection of their flanges to the adapter elements and the connection of the adapter elements to each other, and to test them together. The arrangement described here can also be referred to as a "back-to-back arrangement" of two rotor blades (in particular in a row).

[0011] During test operation, due to the arrangement of the two rotor blades and / or rotor blade segments relative to each other and their attachment to one another, the majority of the loads occurring in the supporting structure and / or in the foundation are therefore only present in the form of vertical forces and / or horizontal forces and no longer in the form of bending moments.

[0012] The rotor blades can be tested for fatigue both with a natural frequency vibration, preferably synchronous, and with quasi-static extreme loads.

[0013] The solution described here also allows for both indoor testing (e.g., in a hall) and outdoor testing (e.g., in the open air). Furthermore, hybrid configurations are possible, in which only part of the test setup, e.g., the test device, is fully or partially covered and / or protected against the elements.

[0014] When testing the rotor blades presented here, which have a length of over 70 m, over 80 m, over 90 m, or over 100 m, either entire rotor blades or rotor blade segments can be tested. A rotor blade segment preferably comprises a section of 30% to 99%, and preferably a section of at least 60% or at least 80%, of the total length of the rotor blade, particularly from the blade root. Testing rotor blade segments has the advantage of reducing the dimensions of the overall test setup as well as the deflections of the rotor blade segment (especially at the tip). This results in a lower required hall height (unless the test is performed outdoors) and lower required excitation energy, since air damping is much lower, thus allowing the use of less expensive excitation equipment.

[0015] When the following refers to a rotor blade or rotor blades, the same applies accordingly to a rotor blade segment or rotor blade segments.

[0016] The longitudinal axis of a rotor blade and / or a rotor blade segment is understood here to be the blade axis that runs in a direction orthogonal to the blade flange plane through the center of the annular blade flange.

[0017] By connecting the rotor blades together, the bending moments occurring between the two blades during testing, particularly at their flange ends, especially during fatigue testing, can be largely eliminated or "short-circuited" and no longer need to be transferred via the supporting structure. This allows for a largely moment-free support structure, as essentially only vertical and / or horizontal forces need to be transmitted, and the bending moments that need to be transferred and introduced into a foundation are reduced to a minimum or at least significantly. In this way, the test hardware and foundation required for the test rig can be reduced to a minimum, which also means considerably lower investment costs.

[0018] The solution described here thus enables a test setup that is significantly less expensive to implement and therefore entails considerably lower investment costs. For example, the investment costs for a test setup described here amount to only about 10-20%, and the time from planning to commissioning is only about 50% of the investment costs and time required for test setups based on conventional testing methods.

[0019] The invention is based, among other things, on the realization that the previous test setup, involving the attachment of a rotor blade to a rigid steel or (steel) concrete structure via the blade flange, always resulted in the test rig being subjected to the full flange bending moments. Transferring these bending moments via the supporting structure into the foundation, in combination with cyclic fatigue loading, requires a very robust construction with high investment costs (sometimes with construction costs per test rig between €15-20 million) and a long construction time.

[0020] The test device is preferably configured to test rotor blades and / or rotor blade segments in various directions, in particular in the flapping direction (deformation / load in the wind direction during system operation, also referred to as "flap-wise") and / or in the pivoting direction (deformation / load in the rotor plane (of the wind turbine), also referred to as "lead-lag-wise") and / or "edge-wise" and / or "flat-wise" (these are the local directions related to the radius of the rotor blade according to the axes of the aerodynamic system: edge-wise is the chord ("cord") direction of the respective profile, flat-wise 90° to it). Preferably, the test device is configured for tests in the first and / or second eigenmode of the rotor blade or rotor blade segment(s), preferably including oscillating components, such as...The load saddle, which preferably corresponds to the (preferably used) test directions "impact and pivot direction". Preferably, these tests are carried out sequentially, e.g., as two uniaxial tests. To simulate the typical service life of a rotor blade, a fatigue test can, for example, include one million to ten million or more load or fatigue cycles, which can last three to twelve months or longer for each tested direction. Preferably, the test setup is designed for combined (simultaneous) tests of the impact and pivot directions.

[0021] The load applied to the rotor blade in a specific direction can be time-invariant or static. Static loads are advantageous for evaluating the stiffness and fracture toughness of the rotor blade. Alternatively, the load can vary over time; in this case, the load can be described as "cyclic." Cyclic loads are advantageous for evaluating the fatigue strength of the rotor blade.

[0022] The loads applied via the excitation device are generally applied in a first and a second direction and with a first and a second frequency, e.g., with different frequencies that may or may not correspond to the resonance or natural frequencies of the test object. The first and second directions preferably run perpendicular to each other and can preferably be orthogonal.

[0023] Especially when exciting the blade at its first or second natural frequency to apply a fatigue load, the cyclic flange moments of very long blades become extremely high, necessitating a very robust and therefore expensive support structure for the rotor blade, and, as mentioned, leading to exceptionally high investment costs. In this respect, the test setup described here offers significant advantages.

[0024] In comparison with existing solutions, in the solution described here the lifting lateral force at the rotor blade flanges preferably does not exceed the self-weight force of the supporting structure or only slightly, so that lifting off is not to be expected or can be prevented by light ballasting.

[0025] According to a preferred embodiment, the first and second adapter elements are rotatably mounted on the support structure about a common axis of rotation. Preferably, the common axis of rotation, particularly during testing, is oriented essentially orthogonally to the longitudinal axes of rotor blades and / or rotor blade segments attached to the first and / or second adapter element during testing.

[0026] For example, the common axis of rotation can be oriented horizontally or vertically, particularly during testing. Furthermore, the common axis of rotation can preferably be adjustable, in particular between a horizontal position and a vertical position, especially during testing.

[0027] This is particularly advantageous in order to be able to conduct tests in different directions.

[0028] It is further preferred that the supporting structure is designed to absorb shear forces, in particular vertical forces and / or horizontal forces, and bending moments, wherein the ratio of the bending moments in kNm to the shear forces to be absorbed by the supporting structure in kN is preferably a maximum of 15, in particular a maximum of 10, a maximum of 5, or a maximum of 3.5.

[0029] According to a preferred embodiment, the test device comprises a foundation, wherein the foundation is designed to absorb shear forces, in particular vertical forces and / or horizontal forces, and bending moments, wherein the ratio of the bending moments in kNm to the shear forces to be absorbed by the supporting structure in kN is preferably a maximum of 15, in particular a maximum of 10, a maximum of 5, or a maximum of 3.5.

[0030] Furthermore, it is preferred that the connection between the supporting structure and the foundation is designed to absorb shear forces, in particular vertical forces and / or horizontal forces, and bending moments, wherein the ratio of the bending moments in kNm to the shear forces to be absorbed by the supporting structure in kN is preferably a maximum of 15, in particular a maximum of 10, a maximum of 5, or a maximum of 3.5.

[0031] The test setup described here is primarily subjected to shear forces, while the bending moments it must absorb are significantly reduced compared to existing solutions, to a maximum of approximately 10% of the bending moments occurring in existing solutions. Conversely, the shear forces that the described test setup must absorb are approximately double those of existing solutions. However, absorbing shear forces is easily implemented for the supporting structure, the foundation, and the connection between the supporting structure and the foundation. Load on the supporting structure during cyclic (fatigue) tests (section forces specified as amplitude) with the solution according to the invention:

[0032] Blade length [m] Bending moment [kNm] Shear forces [kN] Ratio bending moment [kNm] / shear force [kN] 35 500,0 300,0 1,7 70 1.500,0 600,0 2,5 100 3.000,0 1.000,0 3,0 120 5.000,0 1.600,0 3,1 Load on the supporting structure during static (extreme load) tests with the solution according to the invention:

[0033] Blade length [m] Bending moment [kNm] Shear forces [kN] Ratio bending moment [kNm] / shear force [kN] 35 500,0 500,0 1,0 70 1.700,0 1.000,0 1,7 100 4.500,0 1.800,0 2,5 120 7.000,0 2.400,0 2,9 Load on the supporting structure during cyclic (fatigue) tests (fatigue parameters given as amplitude) in the state of the art:

[0034] Leaf length [m] Bending moment [kNm] Shear forces [kN] Ratio bending moment [kNm] / shear force [kN] 35 5.000,0 150,0 33,3 70 15.000,0 300,0 50,0 100 30.000,0 500,0 60,0 120 50.000,0 800,0 62,5 Load on the supporting structure during static (extreme load) tests in the state of the art:

[0035] Blade length [m] Bending moment [kNm] Shear forces [kN] Ratio bending moment [kNm] / shear force [kN] 35 5 000,0 250,0 20,0 70 17.000,0 500,0 34,0 100 45.000,0 900,0 50,0 120 70.000,0 1.200,0 58,3

[0036] In a preferred embodiment, the first and second adapter elements form an angle of 0° to 40°, particularly 0° to 10°, with each other. A preferred further embodiment is characterized in that the first adapter element forms an angle of 0° to 20°, particularly 0° to 5°, with the vertical, and / or the second adapter element forms an angle of 0° to 20°, particularly 0° to 5°, with the vertical.

[0037] According to a preferred embodiment, the longitudinal axis of the first rotor blade or rotor blade segment and the longitudinal axis of the second rotor blade or rotor blade segment form an angle of 180° to 140°, in particular 180° to 170°, with each other. Furthermore, it is preferred that the longitudinal axis of the first rotor blade or rotor blade segment forms an angle of 0° to 20°, in particular 0° to 5°, with the horizontal, and / or that the longitudinal axis of the second rotor blade or rotor blade segment forms an angle of 0° to 20°, in particular 0° to 5°, with the horizontal.

[0038] Furthermore, it is preferably provided that the first adapter element is designed as an adapter plate and / or that the second adapter element is designed as an adapter plate. Plate-shaped adapter elements can be easily connected to the rotor blade flanges, to each other, and to the supporting structure.

[0039] Preferably, the first and second adapter elements are directly connected to each other and to the supporting structure using tension anchors. This allows for a particularly simple solution with corresponding cost advantages.

[0040] Furthermore, preferably one, two, or more spacers are arranged between the first and second adapter elements. The spacer(s) is / are, for example, designed as tubular spacers and / or designed to withstand high compressive forces.

[0041] According to a preferred embodiment, the test device is designed to be demountable and / or transportable. The test device can therefore also be described as mobile.

[0042] The solution described here, with its relatively small and / or lightweight components compared to existing solutions, enables this design in terms of disassembly, transportability, and mobility. This is possible because the test device, due to its lower weight, can be transported between test sites, and only a comparatively simple foundation is required, which is either already present on-site (as a level, load-bearing surface) or can be provided quickly and easily on-site.

[0043] This demountable and / or transportable design has the advantage that the test rig can be transported to a production facility, instead of transporting large rotor blades and / or rotor blade segments, often still in the prototype stage, over long distances, which is complex and expensive. Furthermore, the rotor blades and / or rotor blade segments can be damaged during transport, leading to correspondingly poorer test results and potentially jeopardizing certification or requiring a new test (with the correspondingly high costs and time expenditure). The complex transport of rotor blades from manufacturing to the test bench could be eliminated if the blade could be tested directly during production. Since rotor blade certification is very time-critical for the development of new systems, such long transport times are disadvantageous.A major advantage of the solution described here is therefore the possibility of testing rotor blades directly in the immediate vicinity of the production site, thus saving time and costs for transport.

[0044] Preferably, several components of the test device, in particular all components of the test device except the foundation, are transportable together, for example in a standard container, in particular an ISO container (e.g. a 40-foot ISO container) and / or on a truck, in particular a truck up to 40t, and / or on a semi-trailer, in particular a semi-trailer with maximum external dimensions of 13.68 m × 2.55 m × 4.00 m.

[0045] The excitation device is preferably designed to excite both rotor blades and / or both rotor blade segments simultaneously and / or equally. This can be advantageous, for example, to allow for more options to adjust the load, such as during a certification test.

[0046] Likewise, the excitation device is preferably configured to excite one of the two rotor blades and / or one of the two rotor blade segments. Excitation of one of the two rotor blades and / or both rotor blade segments and / or one of the two rotor blade segments may be sufficient to set both rotor blades and / or both rotor blade segments into vibration. Even if only one of the two rotor blades and / or one of the two rotor blade segments is excited, it may be preferred that the excitation device (or its components) is connected to each of the two rotor blades and / or each of the two rotor blade segments in order to adjust the natural frequencies of both rotor blades and / or both rotor blade segments as similarly as possible.

[0047] As further described, the test device can also be used to test only a single rotor blade and / or a rotor blade segment. In this case, it can be advantageous to have a counter element attached to the second adapter element.

[0048] The excitation device may preferably include or be connected to a control device, wherein the control device is preferably configured to control the excitation of the rotor blade and / or the rotor blade segment and / or the rotor blades and / or the rotor blade segments. Preferably, the control device includes a shutdown mechanism configured to modify and / or terminate the excitation, particularly when a critical condition is exceeded, for example, when a limit value regarding the deflection of the rotor blades and / or the rotor blade segments is reached or exceeded, or when a fault occurs in the control system.

[0049] In a further preferred embodiment, the excitation device comprises one or more actuators. The actuators can be hydraulic, for example in the form of hydraulic cylinders, and / or pneumatic and / or electric. Where details are explained here using the example of hydraulic excitation, these details also apply to pneumatic and / or electric excitation, unless otherwise specified.

[0050] Furthermore, the excitation device is preferably configured to excite the first and second rotor blades or rotor blade segments simultaneously, in particular synchronously and / or at the same frequency, preferably at the first or second natural frequency of the first and second rotor blades or rotor blade segments. For this purpose, at least two actuators, in particular in the form of hydraulic and / or pneumatic and / or electric actuators, are preferably provided, and preferably also at least two controllers, which may be integrated, for example, in the control device and / or in the actuators.

[0051] According to a further aspect of the invention, the aforementioned problem is solved by a method for simultaneously testing two rotor blades and / or two rotor blade segments for a wind turbine, comprising: attaching a first rotor blade or rotor blade segment to a first adapter element, attaching a second rotor blade or rotor blade segment to a second adapter element, connecting the first and second adapter elements to each other, arranging the first and second adapter elements on a support structure, and applying a static and / or cyclic load to the first and / or second rotor blade or rotor blade segment by means of an excitation device.

[0052] The procedure for simultaneously testing two rotor blades and / or two rotor blade segments for a wind turbine includes providing a previously described test device.

[0053] The method for simultaneously testing two rotor blades and / or two rotor blade segments for a wind turbine is preferably further developed in that the first and / or the second rotor blade segment comprises a range of 30% to 99%, preferably a range of at least 60% or at least 80%, of the total length of the rotor blade, in particular from the blade root.

[0054] The method for simultaneously testing two rotor blades and / or two rotor blade segments for a wind turbine is preferably further developed by the fact that the first and the second rotor blade or rotor blade segment are essentially identical.

[0055] The method for simultaneously testing two rotor blades and / or two rotor blade segments for a wind turbine is preferably characterized by synchronously applying a cyclic load to the first and the second rotor blade or rotor blade segment.

[0056] According to a further aspect of the invention, the aforementioned problem is solved by a method for testing a rotor blade and / or a rotor blade segment for a wind turbine, comprising: providing a previously described test device, attaching a first rotor blade or rotor blade segment to the first adapter element, arranging the first adapter element on a supporting structure, and applying a static and / or cyclic load to the first second rotor blade or rotor blade segment by means of an excitation device.

[0057] The procedure for testing a rotor blade and / or a rotor blade segment for a wind turbine includes providing a previously described test apparatus.

[0058] The method for testing a rotor blade and / or a rotor blade segment for a wind turbine is preferably further developed in that the first rotor blade segment comprises a range of 30% to 99%, preferably a range of at least 60% or at least 80%, of the total length of the rotor blade, in particular from the blade root.

[0059] The method for testing a rotor blade and / or a rotor blade segment for a wind turbine further preferably comprises arranging a counter-element, which can also be referred to as a counter-vibration element, on the second adapter element. The counter-element is in particular designed in the form of a single-mass oscillator, preferably adjustable to the natural frequency of the first rotor blade or rotor blade segment.

[0060] The method for simultaneously testing two rotor blades and / or two rotor blade segments for a wind turbine and / or the method for testing one rotor blade and / or one rotor blade segment for a wind turbine is / are preferably characterized by transporting a previously described test device to the test site, preferably in disassembled form.

[0061] The method for simultaneously testing two rotor blades and / or two rotor blade segments for a wind turbine and / or the method for testing one rotor blade and / or one rotor blade segment for a wind turbine is / are further preferably characterized by providing a foundation at the test site.

[0062] The method for simultaneously testing two rotor blades and / or two rotor blade segments for a wind turbine and / or the method for testing one rotor blade and / or one rotor blade segment for a wind turbine is / are preferably characterized by setting up the test device at the test site.

[0063] Preferably, the process steps described here are carried out in the order given. However, depending on the situation and within the bounds of technical feasibility, deviations from this order are also possible.

[0064] According to a further aspect of the invention, the aforementioned problem is solved by using a previously described test device for testing a rotor blade and / or a rotor blade segment for a wind turbine and / or for simultaneously testing two rotor blades and / or two rotor blade segments for a wind turbine.

[0065] These described procedures have features or procedural steps that make them particularly suitable for use with a previously described test device and its advanced training.

[0066] Regarding the advantages, preferred embodiments and details of the individual aspects and their preferred embodiments, reference is also made to the corresponding advantages, preferred embodiments and details described with reference to the other aspects.

[0067] Preferred embodiments are described by way of example with reference to the accompanying figures. These show: Figure 1: a schematic representation of a wind turbine; Figure 2a: a schematic representation of an embodiment of a test device for a fatigue test with two rotor blade segments; Figure 2b: an enlarged view of a detail from Figure 2aFigure 3: a schematic representation of an embodiment of a test device for a static test with two rotor blade segments; Figure 4a: a schematic three-dimensional view of an embodiment of a test device for a fatigue test with two rotor blades; Figure 4b: a schematic side view of the test device according to Figure 4a Figure 4c: an enlarged view of a detail from Figure 4a Figure 4d: an enlarged view of a detail of the test apparatus according to Figure 4a without adapter element and rotor blade; Figure 4e: a schematic three-dimensional view of the test device according to Figure 4a with excitation device; Figure 4f: an enlarged view of a detail of the test device according to Figure 4eFigure 5: a schematic flowchart of an embodiment of a method for simultaneously testing two rotor blades and / or two rotor blade segments for a wind turbine; and Figure 6: a schematic flowchart of an embodiment of a method for testing one rotor blade and / or one rotor blade segment for a wind turbine.

[0068] In the figures, identical or essentially functionally equivalent elements are designated with the same reference numerals. General descriptions usually refer to all embodiments unless differences are explicitly stated.

[0069] Fig. 1Figure 1 shows a schematic representation of a wind turbine 100 for which rotor blades 108 are used. The wind turbine 100 has a tower 102 and a nacelle 104 on the tower 102. An aerodynamic rotor 106 with three rotor blades 108 and a spinner 110 is mounted on the nacelle 104. During operation of the wind turbine, the aerodynamic rotor 106 is set into rotation by the wind and thus also rotates an electrodynamic rotor or generator rotor, which is directly or indirectly coupled to the aerodynamic rotor 106. The electric generator is located in the nacelle 104 and generates electrical energy. The pitch angles of the rotor blades 108 can be changed by pitch motors at the rotor blade roots 109 of the respective rotor blades 108.

[0070] Figure 2aFigure 1 shows a schematic representation of an embodiment of a test device 20 for a fatigue test with two rotor blade segments 108'. Figure 3 Figure 1 shows a schematic representation of an embodiment of a test device 20' for a static test with two rotor blade segments 108'. The two test devices 20, 20' differ in particular with respect to the excitation devices 30a, b, 30'a, b.

[0071] Both test devices 20, 20' are arranged on a foundation 1, which can also be called a test platform.

[0072] Both test devices 20, 20' each comprise a first adapter element 21a in the form of an adapter plate and a second adapter element 21b in the form of an adapter plate. The flanges of the rotor blade segments 108' are attached to these adapter elements, preferably by bolting.

[0073] As particularly in Fig. 2bAs can be seen, the first and second adapter elements 21a, b form an angle α of approximately 40° to each other, with the first adapter element 21a forming an angle β a of approximately 20° to the vertical, and the second adapter element 21b forming an angle β b of 0° to 20° to the vertical.

[0074] Furthermore, the longitudinal axis L of the first rotor blade segment 108' and the longitudinal axis L of the second rotor blade segment 108' form an angle γ of approximately 140° with each other. The longitudinal axis L of the first rotor blade segment forms an angle δa of approximately 20° with the horizontal, and the longitudinal axis L of the second rotor blade segment forms an angle δb of 0° to 20° with the horizontal.

[0075] The test device 20 for a fatigue test with two rotor blade segments 108' according to Fig. 2aThe device comprises an excitation device 30a, b, which includes two partial excitation devices. Each of the partial excitation devices preferably includes a load saddle 32a, b, an actuator 31a, b (for example, in the form of a hydraulic actuator), and is arranged on a concrete block 33a, b. The concrete blocks 33a, b, as well as the foundation 1, can be manufactured on-site at low cost. The partial excitation devices, in particular their load saddles 32a, b, are attached to the rotor blade segments 108' at a distance from the blade root.

[0076] The excitation device 30a, b is designed to excite the rotor blade segments 108' with cyclic fatigue loads and to cause the rotor blade segments 108' to vibrate, whereby deflections D both upwards and downwards occur at the tip of the rotor blade segments 108'.

[0077] In such a fatigue test, a fatigue load is preferably applied by exciting the first or second natural frequency of the rotor blades and / or rotor blade segments (in particular flap-wise and / or lead-lag-wise tests). A preferably synchronous excitation of the two rotor blades and / or rotor blade segments to their natural frequency vibration in the vertical direction can be achieved, for example, via an excitation device 30a, b in the form of hydraulic cylinders 31a, b coupled via load saddles 32a, b.

[0078] In a static test such as in Fig. 3The rotor blade segments 108' are shown being tested quasi-statically under extreme loads. For this purpose, an excitation device 30'a, b with several partial excitation devices can be used. Each of the partial excitation devices preferably comprises a load saddle 32a, b, an actuator 34a, b (for example, in the form of an electric winch) and is arranged on a concrete block 33a, b. The actuators 34a, b deflect the rotor blade segments 108' downwards. The concrete blocks 33a, b can serve as counterweights. Here, too, no or no significant bending moments need to be introduced into the foundation. Only, or primarily, the vertical counterforces of the rotor blade segments 108' and the test loads need to be introduced into the foundation. A foundation 1 for such loads is relatively easy to install, as are the concrete blocks 33a, b.

[0079] In Fig. 2bThe directions of the occurring shear forces Q+, Q- and bending moments M+, M- are also specified.

[0080] In conventional rotor blade test rigs, the bending moment applied to the blade flange must be transferred through the test rig structure into the foundation and the ground. In the test devices 20, 20' described here, the bending moment M+, M- acting on the blade flange is absorbed directly by the second rotor blade or rotor blade segment, which is mounted back-to-back (or flange-to-flange). In this solution, the supporting structure experiences no or only extremely low bending moment loads. Only, or primarily, moderate vertical fatigue loads in the form of shear forces Q+, Q- must be managed. The solution described here therefore results in a test rig for very large rotor blades and / or rotor blade segments at minimal investment costs.

[0081] Both test devices 20, 20' according to the Figures 2a and 3 The test devices 20, 20' are designed to excite rotor blades and / or rotor blade segments in a vertical direction. They can preferably also be designed to excite rotor blades and / or rotor blade segments in a horizontal direction. For this purpose, the test devices 20, 20' can be designed to be adjustable accordingly.

[0082] According to the Figures 2a and 3 The flanges of the two rotor blade segments 108' are arranged "back-to-back," which can also be described as "short-circuiting." This cancels out the flange moments directly between the two flanges. Preferably, two identical rotor blades or rotor blade segments 108' are used for this purpose.

[0083] In the Fig. 4a-4fFigure 1 shows a schematic representation of an embodiment of a test device 200 for a fatigue test with two rotor blades. Tests were carried out here with two identical rotor blades 108.

[0084] The two rotor blades 108 are connected to each other and to the support structure 210 via two adapter plates 121a, b by means of screw connections 215, 216. The adapter plates 121a, b are screwed to each other ("back-to-back") with the pivotally mounted axis of rotation 214 of the support structure 210. Spacers can preferably be arranged between the adapter plates 121a, b.

[0085] The supporting structure 210 is arranged on a foundation 1 via a foundation connection 211, which in operation has to absorb almost exclusively vertical loads.

[0086] The supporting structure 210 comprises two steel profiles 212, for example HEB profiles, which are essentially vertical in operation. These are connected to each other via upper cross braces 213o and a lower cross brace 213u. Furthermore, the pivotally mounted axis 214 connects the steel profiles 212.

[0087] The two adapter plates 121a, b are suspended from the common axis of rotation 214 to enhance the effect of minimizing the transfer of bending moments to the supporting structure 210 and / or the foundation 1. The two adapter plates 121a, b are directly connected to each other by tension anchors 216 and to the supporting structure 210 by tension anchors 215 via the pendulum elements 217 suspended from the axis of rotation 214. The rotor blade flanges can be bolted to the adapter plates 121a, b from their inner surfaces. Preferably, the adapter plates 121a, b are spaced apart from each other.

[0088] The test device 200 further comprises an excitation device 130a, as shown in particular in the Fig. 4e and 4f This can be seen. A load saddle 132a, b is arranged on each of the rotor blades 108, which is preferred when both rotor blades 108 are excited, but also has the advantage when only one rotor blade 108 is excited that the natural frequencies of the two rotor blades can be set as similarly as possible. In the Fig. 4e and 4fIn the test shown, only one rotor blade 108 was excited. For this purpose, an actuator 131a, in this example a pneumatic actuator, is coupled to and controlled by the load saddle 132a to excite the rotor blades 108 at their first natural frequency. The actuator 131a is controlled, for example, by a soft PLC integrated into a PMX measuring amplifier from HBM. By coupling another actuator to the second load saddle 132b, both rotor blades can also be directly excited simultaneously using the test device 200. If only one rotor blade 108 is directly excited via an actuator, the second rotor blade oscillates due to the direct coupling and back-to-back arrangement of the two rotor blades.

[0089] In the experiment with one actuator, both rotor blades 108 swung in a mirror image to the adapter plates (see Figure 4e ), when they were excited at their first natural frequency.

[0090] In a test (not shown) with two actuators, both rotor blades 108 were excited by an actuator on each rotor blade. Both blades oscillated in a mirror image of the adapter plate when excited at their first natural frequency.

[0091] Furthermore, the natural frequency can be changed, e.g., reduced, by applying trim weights, for example in the form of additional load saddles, to the rotor blades 108. This makes it easy to adapt the test setup to different test frequencies.

[0092] Figure 5Figure 1 shows a schematic flowchart of an embodiment of a method (1000) for the simultaneous testing of two rotor blades and / or two rotor blade segments for a wind turbine. Preferably, in step 1001, a test device is first transported to the test site, preferably in disassembled form, and then preferably assembled at the test site in step 1002. Furthermore, preferably, a foundation is provided at the test site if necessary.

[0093] In step 1003, a first rotor blade or rotor blade segment is attached to a first adapter element. In step 1004, a second rotor blade or rotor blade segment is attached to a second adapter element. In step 1005, the first and second adapter elements are connected to each other and, in step 1006, arranged on a support structure before, in step 1007, a static and / or cyclic load is applied to the first and / or second rotor blade or rotor blade segment, whereby the application of the cyclic load to the first and second rotor blade or rotor blade segment can be synchronous.

[0094] Figure 6Figure 2 shows a schematic flowchart of an embodiment of a method (2000) for testing a rotor blade and / or a rotor blade segment for a wind turbine. In step 2001, a first rotor blade or rotor blade segment is attached to the first adapter element, and in step 2002, the first adapter element is arranged on a support structure. Furthermore, it is preferred that in step 2003, a counter element, in particular in the form of a single-mass oscillator, preferably adjustable to the natural frequency of the first rotor blade or rotor blade segment, is attached to the second adapter element. In step 2004, a static and / or cyclic load is then applied to the first second rotor blade or rotor blade segment.

[0095] Preferably, the process steps described here are carried out in the order given. However, depending on the situation and within the bounds of technical feasibility, deviations from this order are also possible.

Claims

1. Testing device (20, 20', 210) for simultaneously testing two rotor blades (108) and / or two rotor blade segments (108') for a wind power installation (100), comprising - a first adapter element (21a) for fastening thereto a first rotor blade (108) or rotor blade segment (108'); - a second adapter element (21b) for fastening thereto a second rotor blade (108) or rotor blade segment (108'); - a support structure (210) to which the first and the second adapter element (21a, 21b) are fastened; - an excitation device (30a,b, 30'a,b) which is configured to apply a static and / or cyclic load to the first and / or the second rotor blade (108) or rotor blade segment (108'); - wherein the first and the second adapter element (21a, 21b) are connected to each other.

2. Testing device (20, 20', 210) according to the preceding claim, characterized in that the first and the second adapter element are fastened to the support structure so as to be rotatable about a common rotation axis, wherein the common rotation axis is preferably aligned so as to be substantially orthogonal to longitudinal axes of rotor blades and / or rotor blade segments that during the testing operation are fastened to the first and / or the second adapter element; and / or wherein the common rotation axis is preferably aligned so as to be horizontal and / or vertical; and / or wherein the common rotation axis is preferably configured so as to be adjustable, in particular adjustable between a horizontal position and a vertical position.

3. Testing device (20, 20', 210) according to at least one of the preceding claims, characterized in that the support structure is configured to absorb lateral forces, in particular vertical forces and / or horizontal forces, and bending moments, wherein the ratio of the bending moments in kNm able to be absorbed by the support structure to the lateral forces in kN able to be absorbed by the support structure is preferably at most 15, in particular at most 10, at most 5, or at most 3.5.

4. Testing device (20, 20', 210) according to at least one of the preceding claims, comprising a foundation, wherein the foundation is configured to absorb lateral forces, in particular vertical forces and / or horizontal forces, and bending moments, wherein the ratio of the bending moments in kNm able to be absorbed by the support structure to the lateral forces in kN able to be absorbed by the support structure is preferably at most 15, in particular at most 10, at most 5, or at most 3.5.

5. Testing device (20, 20', 210) according to at least one of the preceding claims, characterized in that the link between the support structure and the foundation is configured to absorb lateral forces, in particular vertical forces and / or horizontal forces, and bending moments, wherein the ratio of the bending moments in kNm able to be absorbed by the support structure to the lateral forces in kN able to be absorbed by the support structure is preferably at most 15, in particular at most 10, at most 5, or at most 3.5.

6. Testing device (20, 20', 210) according to at least one of the preceding claims, characterized in that the first and the second adapter element mutually include an angle (α) of 0° to 40°, in particular of 0° to 10°, and / or characterized in that first adapter element in relation to the vertical includes an angle (βa) of 0° to 20°, in particular of 0° to 5°, and / or the second adapter element in relation to the vertical includes an angle (βb) of 0° bis 20°, in particular of 0° to 5°.

7. Testing device (20, 20', 210) according to at least one of the preceding claims, characterized in that the longitudinal axis (L) of the of the first rotor blade or rotor blade segment and the longitudinal axis (L) of the second rotor blade or rotor blade segment mutually include an angle (γ) of 180° to 140°, in particular of 180° to 170°; and / or characterized in that the longitudinal axis (L) of the first rotor blade or rotor blade segment in relation to the horizontal includes an angle (δa) of 0° to 20°, in particular of 0° to 5°, and / or the longitudinal axis (L) of the second rotor blade or rotor blade segment in relation to the horizontal includes an angle (δb) of 0° to 20°, in particular of 0° to 5°.

8. Testing device (20, 20', 210) according to at least one of the preceding claims, characterized in that the first and / or the second adapter element are / is configured as an adapter plate, wherein the first adapter element and the second adapter element are preferably connected directly to each other and to the support structure by ties, and / or wherein two or more spacers are preferably disposed between the first and the second adapter element; and / or characterized in that the excitation device comprises one actuator or a plurality of actuators, and / or characterized in that the excitation device is configured to identically excite the first and the second rotor blade or rotor blade segment, in particular in a synchronous manner and / or at the same frequency, preferably at the first or the second inherent frequency of the first and the second rotor blade or rotor blade segment.

9. Testing device (20, 20', 210) according to at least one of the preceding claims, characterized in that the testing device is configured so as to be able to be disassembled and / or transported, wherein a plurality of component parts of the testing device, in particular all component parts of the testing device, with the exception of the foundation, are preferably able to be transported conjointly in a standard container, in particular an ISO container and / or on a motor truck, in particular a motor truck of up to 40 t, and / or on a semitrailer, in particular a semitrailer having maximum external dimensions of 13.68 m x 2.55 m x 4.00 m.

10. Method (1000) for simultaneously testing two rotor blades (108) and / or two rotor blade segments for a wind power installation (100), characterized by: - providing a testing device according to one of the preceding claims 1 to 9; - fastening (1003) a first rotor blade (108) or rotor blade segment (108') to the first adapter element (21a); - fastening (1004) a second rotor blade (108) or rotor blade segment (108') to the second adapter element (21b); - connecting (1005) the first and the second adapter elements (21a, 21b) to each other; - disposing (1006) the first and the second adapter element (21a, 21b) on the support structure; - applying (1007) the static and / or cyclic load to the first and / or the second rotor blade (108) or rotor blade segment (108') by means of the excitation device (30a,b, 30'a,b).

11. Method according to the preceding claim, - characterized in that the first and / or the second rotor blade segment comprises a region of 30% to 99%, preferably a region of at least 60% or at least 80%, of the overall length of the rotor blade, in particular proceeding from the blade root; and / or - characterized in that the first and the second rotor blade or rotor blade segment are of substantially identical configuration; and / or - characterized by applying in a synchronized manner a cyclic load to the first and the second rotor blade or rotor blade segment.

12. Method (2000) for testing a rotor blade (108) and / or a rotor blade segment for a wind power installation (100), characterized by: - providing a testing device according to one of the preceding claims 1 to 9; - fastening (2001) a first rotor blade (108) or rotor blade segment (108') to the first adapter element (21a); - disposing (2002) the first adapter element (21a) on the support structure; - applying the static and / or cyclic load (2004) to the first rotor blade (108) or rotor blade segment (108') by means of the excitation device (30a,b, 30'a,b).

13. Method according to the preceding claim, - characterized in that the first rotor blade segment comprises a region of 30% to 99%, preferably a region of at least 60% or at least 80%, of the overall length of the rotor blade, in particular proceeding from the blade root; and / or - characterized by disposing a counter element (2003), in particular in the form of a single mass oscillator, preferably adjustable to the inherent frequency of the first rotor blade or rotor blade segment, on the second adapter element.

14. Method according at least one of preceding claims 10 to 13, said method comprising the following steps: - transporting (1001) a testing device (20, 20', 210) according to at least one of preceding claims 1 to 9 to the testing site, preferably in the disassembled form; and / or - providing a foundation (1) at the testing site; and / or - erecting (1002) the testing device (20, 20', 210) at the testing site.

15. Use of a testing device (20, 20', 210) according to at least one of preceding claims 1 to 9 for testing a rotor blade (108) and / or a rotor blade segment (108') for a wind power installation (100), and / or for simultaneously testing two rotor blades (108) and / or two rotor blade segments (108') for a wind power installation (100).