TECHNICAL FIELD

[0001] The present subject matter, in general, relates to testing of wind turbine blades, and, in particular relates, to static and fatigue testing of wind turbine blades, arrangements, and fixtures thereof.

BACKGROUND

[0002] Wind turbines convert kinetic energy of the wind into electrical energy. Typically, the wind turbine includes three major components including rotor components, generator components, and structural support components. With the ever increasing demand for generating electricity from renewable source of energy, such as wind, the capacity and size of rotor blades have also increased. One of the many parameters that have to be taken care of while designing wind turbines is to strike a balance between the weight of rotor blades and the required power output, as a slight increase in the size of a rotor blade can increase the weight of the blade to such an extent that the power output gets affected.

[0003] As should be noted, rotor blades also experience several loads during their operation. Once the rotor blades are designed, they are subjected to testing. Testing of rotor blades enables designers to determine the extent to which performance may be affected during its operation. Testing also enables the designers to determine whether the blades possess the requisite strength and service life to withstand loads of all types through their lifetime.

[0004] Generally known testing techniques involve static and fatigue testing of the rotor blades. Static testing determines the ability of blades to withstand extreme loads, such as those caused during natural phenomenon including storm, tornado, and hurricane, during its lifetime. Static testing helps to determine the ultimate strength of the rotor blades. On the other hand, fatigue testing determines the effect of structural defects in the blades during their operation. SUMMARY

[0005] This summary is provided to introduce concepts related to static and fatigue testing of the wind turbine blades. These concepts are further described below in the detailed description. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.

[0006] According to one embodiment, a testing apparatus for static and fatigue testing of wind turbine blades is described. The testing apparatus comprises a foundation disposed substantially parallel to a ground surface, and a base plate substantially co-planar to the ground surface placed on top of the foundation. A blade mounting plate is rotatably mounted on the base plate and adapted to receive the blade vertically above the ground surface in a plane substantially perpendicular to the ground surface. The blade mounting plate being rotatable over the base plate to provide a plurality of testing positions of the wind turbine blade.

BRIEF DESCRIPTION OF DRAWINGS

[0007] The detailed description is described with reference to the accompanying figures. In the. figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and components.

[0008] Figure 1 illustrates a testing apparatus, in accordance with an embodiment of the present subject matter.

[0009] Figure 2 illustrates a side view of the testing apparatus in a testing environment, in accordance with an embodiment of the present subject matter.

[0010] Figure 3 illustrates the testing apparatus, in accordance with another embodiment of the present subject matter. DETAILED DESCRIPTION

[001 1] Conventional energy resources, such as those derived from fossil fuels are non-renewable in nature whose availability has become scarce due to excessive usage. Though energy derived from radioactive fuels, such as uranium are considered sustainable, the cost associated with extraction and processing from such fuels is very high. Thus there has been a constant attempt to produce energy from renewable resources, such as wind, water, and sun. Employing wind turbines in locations that experience constant flow of wind enable generation of wind energy. Typically, such wind turbines include rotor components, generator components, and structural components. As a result of ever growing demand for wind power, the size of wind turbine components, particularly that of the rotor blades has been constantly increasing over the years. As a result, the load acting on the wind turbine blades also increases. To determine the load bearing capability of the blades and the ability of the blades to withstand extreme weather conditions, the blades are tested before installation and during its operation, may be at predefined time intervals during the operation on work sites.

[0012] Typically, blades undergo two types of testing, i.e., the static testing and fatigue testing to achieve the desired certification from certifying bodies. During static testing, the blades are tested to determine whether they can withstand extreme design loads especially from the point of view of safety and strength characteristics, which are essential for a blade to withstand extreme weather conditions. Static testing also helps in verifying the bucking stability in addition to measuring deflection, frequency and strain verification of the blades.

[0013] Generally, static testing of blade involves progressively loading multiple points of the blade and across a single axis. Static testing of blades requires testing setups that are often large, complex, and expensive to setup, use, and maintain. Such complex test setups involves rigid fixed structures commonly referred as testing jigs, load application equipments, such as ballistic weights or hydraulic actuators, loading cables, various fixtures, sensors, controllers, and measurement systems.

[0014] On the other hand, fatigue testing of blades is performed to determine the blade's ability to withstand operating loads during its life cycle. Fatigue testing involves applying loads on more than one axis of the blade, i.e., both in the edgewise or lead-lag and flap-wise directions. In an embodiment, load on each of the edge-wise and flap-wise directions are applied sequentially. In another embodiment, fatigue testing can also be performed on both the flap-wise and edge-wise directions simultaneously, thereby reducing the overall test duration. In one embodiment, the fatigue testing of the blade is carried out by oscillating the blade at a predetermined frequency for a predetermined period of time with the help of an oscillator.

[0015] However, both types of testing suffer from structural as well as functional limitations. For example, both conventional blade static and fatigue testing methods involves disassembly and reassembly of testing fixture and blades from the test jig, each time the test shifts between edge-wise and flap-wise testing. This consumes more time for completing a single test. Further, with the increase in dimensions of blades the deflection achieved during flap-wise testing of such blades also increases. With high deflection, the currently available testing shed and foundation height is no more sufficient and requires a complete overhaul in terms of construction, which considerably increases the capital cost involved in setting up of testing facilities.

[0016] Moreover, the presently known test facilities for performing both flap-wise and edge-wise testing of blades involve separate equipments for each of the flap-wise and edge-wise tests. Equipments assisting in achieving plurality of testing positions of blades during testing, such as hydraulic actuators and hydraulic winches are employed independently for flap-wise and edge-wise testing. Conventional testing carried out using such independent testing equipments consumes enormous time and resources for changing testing equipments from one test to the other. Further, the conventional testing facility often requires huge concrete flooring with high strength concrete for the entire floor area

[0017] In accordance with the present subject matter, a testing apparatus for performing static and fatigue testing of the wind turbine blade is described.

[0018] According to one embodiment, the testing apparatus provides for both static and fatigue testing of rotor blade. In one implementation, the testing apparatus comprises a foundation, a base plate, and a blade mounting plate rotatably mounted on the base plate. The testing apparatus includes at least one swiveling element disposed between the blade mounting plate and the base plate. The testing apparatus further includes at least one derrick pivotably attached to the foundation and at least one fixture capable of being disposed on the surface of the blade. According to one embodiment, the at least one fixture is controlled by a pulling mechanism disposed on the derrick.

[0019] Further, the at least one swiveling element is rotated based on a plurality of testing positions of the blade, i.e., flap-wise and edge-wise positions. For testing, the blades are positioned vertically with respect to foundation of the testing apparatus which is placed horizontally to the ground surface. The vertically positioned blades are rotated from one position to the other with the help of the swiveling element disposed between the blade mounting plate and the base plate of the testing apparatus. The rotation of the blade enables shifting from one testing position to the other without having to disassemble and reassemble the blade from the blade mounting plate while shifting the testing position from edge-wise to flap- wise and vice versa. According to one embodiment, the swiveling element is a rotatable bearing assembly. The rotation of vertically positioned blade eliminates the complexity attached with the disassembly and reassembly of fixtures and blade of the testing apparatus in addition to reducing the time required for changing from one test position to the other. [0020] The manner in which the static and fatigue testing is carried out using the testing apparatus is described in the forthcoming description. Before describing the method of performing the static and fatigue testing, a brief description of the process of setting up the testing environment is provided below.

[0021] The process of setting up the testing apparatus involves preparing a foundation for holding the blade to be tested and the other components of the testing apparatus. According to an embodiment, the foundation can be made of concrete material. The foundation of the present subject matter requires substantially less floor area as the blade is being mounted vertical to the ground. According to an embodiment, the foundation placed substantially parallel to a ground surface, has a crevice in the centre to accommodate actuation element which is used for shifting the position of the blade depending on the type of test performed. In an embodiment, the actuation element can be a hydraulic jack. The testing apparatus includes a base plate placed on top of the foundation and substantially co-planar to the ground surface. According to an embodiment, the base plate is anchored to the foundation in such a fashion that the centre of the base plate coincides with the vertical axis of the blade in mounted condition. Further, the base plate is disposed in a manner that it extends substantially equidistant on both sides from its centre such that a substantial portion of the top surface of the foundation on either side of the crevice is juxtaposed by the extending portion of the base plate. According to an embodiment, the base plate can be made of concrete material.

[0022] The blade to be tested is capable of being mounted on top of a blade mounting plate. The blade mounting plate is rotatably mounted to the base plate through a plurality of swiveling elements. According to an embodiment, the plurality of swiveling elements is rotating bearing assembly disposed in the space between the base plate and the blade mounting plate. The blade mounting plate is capable of being tilted by the actuation of the hydraulic jack, Which enables easy assembly of the blade on to the blade mounting plate. According to an embodiment, the position of the blade can be shifted from the flap-wise direction to the edge-wise direction. In another embodiment, the blade position can be changed for fatigue testing after completion of static testing. In an embodiment, the blade mounting plate is structurally capable of being rotated so as to minimize the time required for assembly and disassembly of the blades for changing from one testing position to the other, for example, from the flap-wise direction to the edge- wise direction, and/or from one test to the other, for example, from fatigue testing to static testing.

[0023] The testing apparatus thus prevents the disassembly and reassembly after rotation of the fixture and blade while shifting the testing position from edgewise to flap-wise and vice versa. Further, the vertical mounting of the blade also ensures lesser utilization of concrete. The testing apparatus is also capable of subjecting blades to both fatigue and static testing with substantially lesser number of mounting fixtures as the assembly involves base plate and blade mounting plate in combination with the plurality of rotatable bearing assembly and the hydraulic jack to achieve all testing positions. Thus facilitating shifting from one testing position to the other by rotation of the blade mounting plate without the need for disassembling and reassembling the blades at the end of each test carried out in the testing apparatus, thereby reducing the total time required for testing the blades. Further, as the blade is capable of being mounted vertically to the ground surface, the total area * occupied by the foundation of the testing apparatus has become substantially less and thus has eliminated the need for separate and large foundation and flooring with high strength concrete for the entire floor area.

[0024] Specific details of several embodiments of the apparatus and the method for performing static and fatigue testing on the blades are described below with reference to particular testing components and associated procedures. In other embodiments, the components and associated methods can have other arrangements. Several details describing structures and processes that are well-known and often associated with static and fatigue testing, but that may unnecessarily obscure some significant aspects of the disclosure, are not set forth in the following description for purposes of clarity. Moreover, although the following disclosure sets forth several embodiments of different aspects of the invention, several other embodiments can have different configurations or different components than those described in the forthcoming section. As such, the present disclosure and associated technology can encompass other embodiments with additional elements and/or other embodiments without several of the elements described below with reference to Figures 1-2.

[0025] Figure 1 illustrates the testing apparatus 100, in accordance with an embodiment of the present subject matter. The testing apparatus ^' 100 includes a foundation 102 and a base plate 104 disposed horizontally juxtaposing the top surface of the foundation 102. The base plate 104 is adapted to support a blade mounting plate 106 to which a blade 110 is capable of being mounted. The blade mounting plate 106 is rotatably mounted on the base plate 104 through a roller bearing assembly 108 that is disposed in the gap between the base plate 104 and the blade mounting plate 106. The blade 110 is mounted on the blade mounting plate vertically above the ground surface in a plane substantially perpendicular to the ground surface. The blade 110 is mounted in such a manner that the longitudinal axis of the blade coincides with the central perpendicular axis of the blade mounting plate 106, the base plate 104, and the foundation 102.

[0026] The blade referred herein may in general be any kind of blade of a wind turbine. In the context of the present subject matter, the term blade refers to a complete blade or a portion of the blade (referred to as blade segment). In one implementation, the blade 110 may be provided with a flange by which the blade is connected to the blade mounting plate 106 of the testing apparatus 100. The rotor blade 110 assist in converting wind energy into low speed rotational energy. The low speed rotational energy is converted into high speed rotational energy capable of generating electricity by an electric generator and a gearbox component (not shown) in addition to other control electronics. [0027] According to one embodiment, the blade 110 is provided with one or more loading fixtures 114-1, 114-2, and 114-3 at one or more loading points. In one implementation, the loading fixtures 114-1, 114-2, and 114-3 are fastened to the blade 110 via one or more fastening elements, such as bolts and nuts.

[0028] The testing apparatus 100 further comprises one or more derrick structures 112-1 and 112-2 that are hinged to the foundation 102 at points 128-1 and 128-2 respectively. A derrick is a lifting device having a tower hinged freely at the bottom. The derrick structures 112-1 and 112-2 are primarily used during the static testing of the blade 110. During the fatigue testing of the blade 110, the derrick structures 112-1 and 112-2 are used as a platform for supporting the blade 110. The derrick structures 112-1 and 112-2 are so hinged that they will have two directional movements in a single plane. Each of the derrick structures 112-1 and 112-2 is capable of withstanding the weight of the blade 110. In one embodiment, the derrick structures 112-1 and 112-2 are used as a supporting crane (described in Figure 3), which in combination with hydraulic jack 202 (shown in Figure 2) enables mounting of the blade 110 on the blade mounting plate 106. One or more roller pulleys 116-1 to 116-6 are disposed longitudinally on the derrick structure such that the roller pulley 116-1 to 116-6 on each derrick structure 112-1 and 112-2 facilitates the pulling of the loading fixtures 114-1 to 114-3. In one implementation, load cells 118- 1 to 118-6 are disposed on each side of the loading fixture 114-1 to 114-3 for measurement of load on the blade.

[0029] According to an embodiment, wire ropes or load cables are connected at its one end to the loading fixture 114-1 to 114-3 and at its other end to a loading winch assembly 120-1, 120-2, 120-3, 120-4, 120-5, and 120-6 through the hinges 128-1 and 128-2. The loading winch assembly 120-1, 120-2, 120-3, 120-4, 120-5, and 120-6 controls pulling of the blade depending up on the type of test and the desired bending of the blade 110. [0030] According to another embodiment, the motion of the derrick structures 112-1 and 1 12-2 are controlled by means of one or more winch assemblies. In one implementation, a derrick control winch assembly 122 controls the angle of inclination of the derrick structures 1 12-1 and 1 12-2 desired during different testing position. For example, the desired angle of inclination of the derrick structures 112-1 and 112-2 may be high for flap- wise testing as compared to that of edge-wise testing.

[0031] The derrick structures 1 12-1 and 1 12-2 are controlled by plurality of lines powered by the hydraulic winch assembly. In an embodiment, the plurality of lines is wire ropes or loading cables. Controlling of the tower by the winch assembly allows the derrick to move in all four directions with two directional movements in a single plane.

[0032] The derrick structures 112-1 and 112-2 are capable of controlling the load applied on the blade 110 during the static testing by means of a plurality of rope pulleys 1 16-1 to 116-6 disposed longitudinally at various points on the derrick structure 112-1 and 1 12-2. The plurality of rope pulleys 1 16-1 to 1 16-6 is linked to a plurality of loading fixtures 114-1 to 114-3 mounted at predetermined loading points along the length of the blade 1 10. The loading cables are attached to the loading fixtures 1 14-1 to 1 14-3 at one end and are facilitated by the plurality of rope pulleys 1 16-1 to 1 16-6 to be controlled by the winch assembly. The derrick control winch assembly enables load to be applied on the blade 110 during the testing process. In another embodiment, load can be applied using hydraulic actuators or by hanging ballistic weights. A plurality of load cells 1 18-1 to 1 18-6 is disposed in the load cable line between each load point of the loading fixture and the corresponding rope pulley for measuring the load applied to the blade 1 10. According to an embodiment, a plurality of sensors is disposed on the blade to measure strains, deformations, and deflections on the blade during the testing process. [0033] Further, the motion of derrick structure 112-1 and 112-2 is capable of being controlled by one or more derrick actuation assembly. According to an embodiment, the derrick actuation assembly is interchangeably called as a derrick control winch assembly or a hydraulic winch assembly. According to an embodiment, the testing apparatus 100 comprises a hydraulic winch assembly that enables adjusting the one or more derrick structures 112-1 and 112-2. According to an embodiment, the testing apparatus 100 further comprises another hydraulic winch assembly for locking the one or more derrick structures 112-1 and 112-2 in a desired angle of inclination. Further, according to an embodiment, the testing apparatus 100 includes yet another hydraulic winch assembly for adjusting the angle of inclination of the one or more derrick structures 112-1 and 112-2.

[0034] In one implementation, the testing apparatus 100 further comprises a derrick control winch assembly 124 for locking the derrick structures 112-1 and 112- 2 at an angle of inclination required for a particular type of test. Further, in another implementation, the testing apparatus 100 comprises the derrick control winch assembly 126 for adjusting the position of the derrick structures 112-1 and 112-2 while carrying out a particular test. The derrick control winch assembly 126 adjusts the position of the derrick structures 112-1 and 112-2 with the help of wire rope that connects the poles 130-1 and 130-2 of the derrick structures 112-1 and 112-2.

[0035] According to one embodiment, the foundation 102, the base plate 104, and the blade mounting plate 106 may be designed in a rectangular shape. The foundation 102 may be of about 7000 millimeter (mm) in length and 5000 mm of width.

[0036] According to one embodiment, the rope pulleys 116-1 to 116-6 are attached to fixed anchors 132 through fixed guy cables 134, thus holding the derrick structures 112-1 and 112-2 and preventing them from bending during the testing. The fixed guy cable 134 basically counters rection force during the testing. [0037] It is to be understood that the embodiment described above should not be construed as a limitation, the testing apparatus can be designed in any other shape or size suitable to perform the above mentioned functions, and can be made up of any suitable material with which strength as well as portability of the testing apparatus 100 can be achieved. Further, the components of the testing apparatus 100 described herein can have a variety of other possible arrangements not described herein for the sake of simplicity.

[0038] Figure 2 illustrates a side view of the testing apparatus in a testing environment, in accordance with an embodiment of the present subject matter. According to an embodiment, the foundation 102 of the testing apparatus 100 has a crevice 208 in the centre to accommodate actuation element which is used for shifting the position of the blade 110 depending on the type of test performed. In an embodiment, the actuation element can be a hydraulic jack 202. The base plate 104 that is placed on top of the foundation 102 is anchored to the foundation in such a fashion that the centre of the base plate 104 coincides with the vertical axis of the blade 110 in mounted condition. Further, the base plate 104 is disposed in a manner that it extends substantially equidistant on both sides from its centre such that a substantial portion of the top surface of the foundation 102 on either side of the crevice 208 is juxtaposed by the extending portion of the base plate 104.

[0039] According to an embodiment, the hydraulic jack 202 is attached to a blade mounting plate 106 at a coupling point 204 which assists tilting the blade mounting plate 106 in a swiveling plane during assembly/disassembly of the blade 110. The blade mounting plate 106 is also capable of being rotated perpendicular to the swiveling plane by a rotatable bearing assembly 108. This ensures that the blade is capable of being fatigue and static tested along flap-wise and edge- wise directions. The rotatable bearing assembly 108 is actuated by any actuating means known in the art. In one embodiment, the rotatable bearing assembly 108 is actuating by a motor assembly (not shown in the figure). [0040] According to another embodiment, the rope pulleys 1 16-1 to 1 16-6 are attached with stay cables 206-1 to 206-6 respectively that allows holding the derrick structures 1 12-1 and 112-2 and prevents them from bending during the testing.

[0041] The static testing is carried out at various testing positions of the blade 1 10, for example, flap- wise testing position, and edge- wise testing position of the blade 110. At one testing position, starting loads are applied at the loading points on the blade 110. In subsequent cycles, the loads at the loading points are increased slowly up to the respective ultimate loads predetermined for the blade 110. The load can be held for predefined time at the loading point and can be released slowly thereafter. During the process, measurement of strain, deflection, or deformations of the blade is performed by sensors disposed on the blades, and the measured data is analyzed to determine strength and load bearing capacity of the blade 110. The same testing process is repeated for the other testing position. According to the present subject matter, once the blade 110 is tested at one testing position, moving to the other testing position can be achieved by rotating the blade mounting plate 106 about its longitudinal axis using the plurality of roller bearings 108.

[0042] The testing of the blade 1 10 is done by applying load at each of the loading points along the flap-wise and edge-wise directions simultaneously. In particular, while static testing the blade 110 is pulled with the help of one or more derrick structures 112-1 and 112-2 along the vertical axis, flap-wise, and edge-wise in order to measure deflection and strain on the blade. The loading points and loads to be applied thereon are predetermined and are applied through the plurality of load cables whose one end is connected to the loading fixture 1 14-1, 114-2, 1 14-3, and the other end connected to the one or more hydraulic winch assemblies. In an implementation, while testing, a different load is applied at each loading point. For example, if the load is to be applied at three predetermined locations, depending on the type of testing, different loads are applied at each of the three predetermined locations, i.e., load XI is applied at the first location, load X2 is applied at the second location, and load X3 is applied at the third location.

[0043] As in the case of the static testing, the fatigue testing of the blade 1 10 is also carried out in both the flap-wise and edge-wise directions. The fatigue testing of the blade 110 helps identifying the structural defects occurred during design or manufacturing process of the blade 110. In one embodiment, the fatigue testing of the blade 110 is carried out by oscillating the blade 110 at a pre-determined frequency for a predetermined period of time. For example, during the fatigue testing, cyclic loads of variable amplitude is applied on the blade 1 10. Due to constant cyclic loads, the amplitude varies at different radial positions of the blade 1 10.

[0044] During the fatigue testing, the blade 1 10 is oscillated at a predetermined frequency. In one embodiment, the pre-determined frequency at which the blade 110 is oscillated in the flap or edge directions using an oscillator 210 is the resonant frequency of the blade 110. In an embodiment, the oscillator 210 is disposed suitably at a predetermined location on the plurality of loading fixtures 1 14- 1 , 1 14-2, and 114-3. In one implementation, the oscillator 210 is a hydraulic servo motor. In another implementation, the blade 1 10 is oscillated by the hydraulic jack 220 which provides controlled frequency vibration during the fatigue testing of the blade 1 10.

[0045] In an embodiment, oscillating the blade 1 10 at its resonant frequency ensures that the forces imparted by the oscillator 210 on the blade 110 to maintain the oscillations are kept to a minimum. In one implementation, the oscillator 210 is controlled by software, which when executed enables controlling the amplitude and phase of the oscillation to sustain the blade 110 in its resonance frequency for a predetermined period of time not exceeding the threshold design value, during the fatigue testing. [0046] Further, as the modern blades are made of composite and carbon fibers the flexibility of such blades increases. Thus the flap-wise deflection of such blades varies in the range of approximately 10 to 25 meters. As the blade is now capable of being mounted vertically, the need to mount the root of the blade at a location very high which is practically difficult as it involves huge and separate investment has been eliminated. Moreover, the vertical mounting of blade has ensured that blades of length ranging approximately 60 meters to 100 meters can be handled by the testing apparatus of the present subject matter.

[0047] According to an embodiment, a method for static and fatigue testing of a wind turbine blade 110 using the testing apparatus 100 is described. The static testing of the blade 110 is performed at a testing position when the orientation of the blade is in a flap-wise direction. Similar static testing of the blade 110 is also performed at a testing position when the orientation of the blade is in an edge-wise direction. In an embodiment, the plurality of testing positions includes an inclined position of the blade. The inclination of the blade is controlled by the derrick structures using the one or more derrick control winch assemblies. The method further includes shifting the blade 110 from one testing process, for example from the static testing to the fatigue testing. The shifting is performed with the help of at least one swiveling element 108 that is disposed between the blade mounting plate 106 and the base plate 104. In an embodiment, the swiveling element 108 used for shifting the direction of the blade 110 is a rotatable bearing assembly. According to an embodiment, the method further includes providing the plurality of testing positions using the at least one actuating element 202, the at least one derrick structure 112-1 and 112-2 and the at least one derrick control winch assembly 122, 124, and 126. In an embodiment, the actuating element 202 is a hydraulic jack that enables tilting of the blade mounting plate 106. The at least one derrick structure 112-1 and 112-2 is hinged to the foundation 102 and has freedom of rotation in all four directions, while the derrick control winch assemblies 122, 124, and 126 enables the derrick structures 1 12-1 and 1 12-2 to be rotated and disposed in a plurality of positions which in turn controls the deflection of the blade 110. According to an embodiment, the method includes measuring the static load on the blade 110 when the blade 1 10 is disposed in at least one of the plurality of testing positions. The method also includes measuring the fatigue load on the blade 1 10 when the blade 110 is disposed in at least one of the plurality of testing positions. According to an embodiment, the method includes measuring the static and fatigue loads acting on the blade 1 10 using a plurality of load cells 1 18-1 to 1 18-6.

[0048] Figure 3 illustrates the testing apparatus 100 of Figure 1, in accordance with another embodiment of the present subject matter. The testing apparatus 100 as depicted in this figure is designed for assisting in loading and unloading of the blade 1 10 to/from the blade mounting plate 106 (shown in Figure 1). During the assembly of the blade 110 on the testing apparatus 100, as depicted in Figure 2, the hydraulic jack 202 tilts the blade mounting plate 106 such that the blade 1 10 can be mounted horizontally with the help of the derrick structures 1 12-1 and 1 12-2 with stay cables 206-1, 206-2, 206-3, 206-4, 206-5, and 206-6 fixed in required positions that acts as a crane hoisting the blade 110 using a crane hook 304, which is controlled by a crane hook actuation winch assembly 302. In another embodiment, the derrick structures 1 12-1 and 1 12-2 are made of high strength material that the derrick structures 1 12-1 and 1 12-2 can handle the loading, unloading and assembly of the blade 1 10 in the testing apparatus 100. Thus the derrick structures 112-1 and 1 12-2 of the present subject matter eliminates the need for a separate crane to be employed in the testing facility for loading/unloading/assembly of the blade 1 10 thereby providing a cost effective testing apparatus 100.

[0049] According to one embodiment, the derrick structures 1 12-1 and 1 12-2 are attached to fixed anchors 306-1 and 306-2 through fix guy cables 308-1 and 308- 2, thus holding the derrick structures 1 12-1 and 112-2 and preventing them from bending during the testing. In this embodiment, the derrick control winch assembly (126) can be used for hoisting purposes and the crane hook actuation winch assembly 302 can be used for mast adjustment purposes.

[0050] Although the subject matter has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible. It is to be understood that the appended claims are not necessarily limited to the features described herein. Rather, the features are disclosed as embodiments of the testing apparatus.