Engine component with structural section

Abstract

An apparatus and method for forming an engine component of a turbine engine, the engine component comprising: a wall defining an interior; a plate portion defining a portion of the wall, the plate portion comprising: an outer wall; an inner wall spaced apart from the outer wall to define a wall gap; and a structural section formed within the wall gap, the structural section comprising at least one structural element. The method includes calculating a factor and adjusting a variable until the factor is between a given range.

Description

[0001] This application is a divisional application of the invention patent application with application number 202210010865.0 filed on January 5, 2022 and invention name “Engine component with structural segment”. Technical Field

[0002] The present disclosure generally relates to structural segments in engine components. Background Art

[0003] A turbine engine, particularly a gas or combustion turbine engine, is a rotary engine that extracts energy from the flow of combustion gases through the engine to a plurality of rotating turbine blades, which may be arranged in a plurality of turbine blade assemblies including disks, blades and roots.

[0004] Turbine speed is limited by the centrifugal stresses that can be applied to the disk, blades, and root. High horsepower does not necessarily equate to high output speed. Higher horsepower and speeds are available in specialty turbines and are often specified for large centrifugal compressors. These turbines require very careful examination of transverse critical speed, torsional critical speed, radial bearing stability, thrust bearings, balance, and allowable flange loads.

[0005] The Campbell diagram is often used to determine the effects of multiple excitation frequencies in a turbine. The excitation frequencies that occur at various speeds correspond to severe blade vibrations. Summary of the invention

[0006] In one aspect, the present disclosure is directed to an engine component for a turbine engine, the engine component comprising: a wall including an inner wall and an outer wall spaced from the inner wall to define a wall gap and bound an interior; a structural segment defining a portion of the wall, the structural segment including at least one structural element disposed between the inner wall and the outer wall in an orientation defined by a structural element angle; wherein a frequency factor determined by a modulus, an area, and a moment of inertia, each associated with the structural segment, is between 1 and 1.4.

[0007] In another aspect, the present disclosure relates to a method of forming a test engine component for manufacturing an engine component, the method comprising modeling a plate portion, the plate portion including an outer wall, an inner wall spaced from the outer wall to define a wall gap, and a structural segment formed within the wall gap, the structural segment including at least one structural element extending between the inner wall and the outer wall, the structural element defining at least one variable; calculating a frequency factor determined by a modulus, an area, and a moment of inertia associated with the plate portion; and adjusting at least one of the wall gap or at least one variable until the frequency factor is between 1.0 and 1.4 to define an adjusted plate portion; forming the test engine component having the adjusted plate portion.

[0008] In another aspect, the present disclosure relates to a method of forming a test blade for manufacturing a blade, the method comprising modeling a baseline blade to define a baseline plate portion; determining a set of baseline modal frequencies for the baseline plate portion during a simulation operation; modeling a modified blade to define a modified plate portion, the modified plate portion having an outer wall, an inner wall spaced from the outer wall to define a wall gap, and a structural segment defining a portion of the wall, at least one structural element being disposed within the wall gap; determining a set of modified modal frequencies for the modified blade during a simulation operation; comparing the set of modified modal frequencies to the set of baseline modal frequencies; in the event that the set of modified modal frequencies results in a resonant condition in the modified blade, adjusting the structural segment to define a tuned structural segment, and modeling the tuned blade to define a tuned plate portion having the tuned structural segment; and forming a test blade having a structural segment that matches one of the modified plate portion or the tuned plate portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In the attached picture:

[0010] Figure 1 is a schematic cross-sectional view of a turbine engine for an aircraft.

[0011] Figure 2 is used for Figure 1 A perspective view of a turbine blade of a turbine engine, comprising structural segments shown in cutaway portions of the drawing.

[0012] Figure 3 yes Figure 2 Cross section of a turbine blade showing the wall gap in which the structural segment is located.

[0013] Figure 4 yes Figure 3 An enlarged view of the structural segment.

[0014] Figure 5 yes Figure 4 A perspective view of a portion of a structural segment.

[0015] Fig. 6A is a schematic diagram of a baseline blade, a turbine blade without structural segments.

[0016] Figure 6B This is a schematic diagram of the baseline board. Fig. 6A A model of at least a portion of a baseline blade.

[0017] Figure 6C is the corresponding Campbell diagram for the baseline blade with the baseline plate section.

[0018] Fig. 7A is a schematic diagram of a modified blade, wherein the turbine blade has a modified structural section.

[0019] Figure 7Bis a schematic diagram of the modified board section, Fig. 7A A model of at least a portion of the modified blade.

[0020] Figure 7C is the corresponding Campbell diagram for the modified blade with modified plate section.

[0021] Fig. 8A is a schematic diagram of a turbine blade, showing a tuned blade having a tuned structural section.

[0022] Figure 8B is a schematic diagram of the tuning board section. Fig. 8A A model of at least a portion of a tuning blade.

[0023] Figure 8C is the corresponding Campbell diagram of the tuning blade with the tuning plate section.

[0024] Fig. 9 is formed for manufacturing Figure 2 Flow chart of a method for testing a blade in a blade.

[0025] Fig.10 is a perspective view of an exemplary structural segment according to an aspect disclosed herein.

[0026] Fig.11 is a perspective view of an exemplary structural segment according to another aspect disclosed herein. DETAILED DESCRIPTION

[0027] Aspects of the disclosure described herein relate to a structural segment that defines crystallographic and spatial directions selected to affect the mechanical dynamic response of an engine component in a desired manner, and more specifically, defines a range of values ​​of a frequency factor related to the modulus, moment of inertia, and area of ​​a portion of the engine component. For purposes of illustration, the disclosure will be described with respect to a turbine blade for a turbine of an aircraft gas turbine engine. However, it will be understood that the aspects of the disclosure described herein are not limited thereto and may have general applicability within engines (including compressors) and in non-aircraft applications (e.g., other mobile applications and non-mobile industrial, commercial, and residential applications).

[0028] Depending on the operating environment, desired durability, and / or operational lifecycle of the engine component, the process of manufacturing an engine component using structural segments formed from any anisotropic material - as a non-limiting example, a single crystalline material or a single crystal material (e.g., RENE N5 via known additive manufacturing techniques) - needs to consider the ability of the engine component to perform as expected when subjected to various external influences. For example, in the case of turbine blades used in a gas turbine engine, the blades need to perform in a desired manner to provide desired thermal mass or heat transfer characteristics, internal cooling airflow characteristics, external aerodynamic characteristics, and structural dynamic characteristics. Currently, manufacturing turbine blades that can appropriately respond to airflow, thermal, structural, and aerodynamic performance requirements has been achieved through manufacturing test blades and subjecting each blade to various physical tests of performance - thermal, structural, and aerodynamic.

[0029] Thus, the manufacturing process in this example - a turbine blade for a gas turbine engine - can proceed as follows. Starting with an existing blade, it is modified to improve its internal airflow, heat transfer and / or aerodynamic characteristics, and the structural dynamic response of the modified blade is also evaluated. If the structural dynamic response is unacceptable, the structure of the turbine blade (walls, fillets, thickness, ribs, materials used) needs to be modified in view of the modifications. These modifications in turn affect the heat transfer, airflow or aerodynamic characteristics of the blade. The process starts over with additional physical testing. This process, testing, modification, and then retesting may require multiple iterations of the test blade because the highly interdependent and nonlinear variables that affect the thermal and aerodynamic characteristics of the blade, the internal and external cooling fluid flow behavior, the external forces and inertial forces (both transient and steady state) require the manufacturing and testing of the blade. Although computer simulation can help and is used in the art to solve such engineering problems, this process still requires the manufacture and physical testing of modified structural segments (e.g., test turbine blades), usually several such structural segments, before any meaningful insights are obtained on the appropriate design required. Therefore, it is necessary to define a narrowed or more limited category of structural segments that are worth testing. This definition described herein takes into account the competing interests of optimal thermal, aerodynamic, internal airflow, and structural dynamic response.

[0030] During the process of routinely manufacturing and testing hundreds of turbine blades in the present process described, it was unexpectedly discovered that design modifications responsive to structural dynamics could be considered while redesigning to accommodate thermal, aerodynamic, and internal fluid flow requirements. More specifically, it was discovered that there was a value that related the structural dynamic characteristics of the blade to a range of modifications considered to account for the thermal and fluid dynamics of the blade prior to selecting a blade for manufacturing and testing. Furthermore, the inventors discovered that this value was an advantageous range limit to restrict the selection of acceptable blades, thereby significantly reducing the time spent redesigning and physically testing turbine blades. This value, called the frequency factor ("Ff"), was developed based on experience in designing turbine blades and may also be used for other structures with thermal, fluid, and structural dynamic requirements.

[0031] As used herein, a "structural segment" is an engine component, such as a turbine blade or a portion thereof. The structural segment includes an anisotropic material, such as a single crystalline material. The structural segment includes one or more pins, turbulators, matrices, and a wall defining a gap in which the pins, turbulators, or matrices are arranged.

[0032] As used herein, a "structural element" is a portion of a structural segment, as non-limiting examples, a pin, a turbulator, a matrix, and a wall defining a gap in which the pin, turbulator, or matrix is ​​disposed. A structural element may be of any shape and extend in a linear or curved direction.

[0033] As used herein, a "plate section" is a mathematical representation of an engine component or a portion of an engine component.

[0034] As used herein, an "anisotropic material" is a material that has properties that vary with crystallographic orientation. To determine the frequency factor ("Ff") of a particular blade, it was found that the modulus of the anisotropic material can be expressed adequately using the effective isotropic modulus and the maximum and minimum values ​​without any significant loss of accuracy. While the goal is to select an appropriate grain angle for an anisotropic material relative to another angle defining a structure extending within the internal passage (as explained in more detail below), it was found that using the overall effective isotropic value E o and E, which represent the maximum and minimum values ​​of the modulus max 、E min (See equation (1)) It is sufficient to express the anisotropic material modulus.

[0035] As used herein, a "baseline blade" is an example of a physical engine component, such as an existing turbine blade, for which improvement or modification is desired.

[0036] As used herein, a “modified blade” is an example of a physical engine component that is a modification of a baseline blade.

[0037] As used herein, a "tuning vane" is an example of a physical engine component that meets all desired requirements.

[0038] As used herein, a "test blade" is an example of a physical engine component that is physically tested, and a test blade, a modified blade, and a tuned blade may all be one of the same or separate physical engine components.

[0039] As used herein, the term "upstream" refers to the direction opposite to the direction of fluid flow, while the term "downstream" refers to the direction in the same direction as the direction of fluid flow. The terms "front" or "forward" refer to in front of something, and "rear" or "rearward" refer to behind something. For example, when used in relation to fluid flow, front / forward may refer to upstream, and rear / rearward may refer to downstream.

[0040] Furthermore, as used herein, the terms "radial" or "radially" refer to directions away from a common center. For example, in the overall context of a turbine engine, radial refers to directions along a ray extending between a central longitudinal axis of the engine and an outer engine circumference. Furthermore, as used herein, the terms "group" or a "group" of elements may be any number of elements, including only one element.

[0041] All directional references (e.g., radial, axial, proximal, distal, above, below, upward, downward, left, right, lateral, front, rear, top, bottom, up, down, vertical, horizontal, clockwise, counterclockwise, upstream, downstream, forward, backward, etc.) are used only for identification purposes to help the reader understand the present disclosure and do not constitute limitations, especially limitations on the position, orientation, or use of the various aspects of the present disclosure described herein. Unless otherwise stated, connection references (e.g., attachment, connection, connection, and engagement) should be interpreted broadly and may include intermediate structural elements between sets of elements and relative movement between elements. Therefore, connection references do not necessarily infer that two elements are directly connected and have a fixed relationship to each other. The exemplary drawings are for illustrative purposes only, and the dimensions, positions, orders, and relative sizes reflected in the attached drawings may vary.

[0042] Figure 1 1 is a schematic cross-sectional view of a gas turbine engine 10 for an aircraft. The engine 10 has a generally longitudinally extending axis or engine centerline 12 extending from a front 14 to an aft 16. The engine 10 includes, in downstream serial flow relationship, a fan section 18 including a fan 20, a compressor section 22 including a supercharger or low pressure (LP) compressor 24 and a high pressure (HP) compressor 26, a combustion section 28 including a combustor 30, and a turbine section 32 including an HP turbine 34 and an LP turbine 36.

[0043] The fan section 18 includes a fan case 40 surrounding the fan 20. The fan 20 includes a plurality of fan blades 42 radially arranged around the engine centerline 12. The HP compressor 26, the combustor 30, and the HP turbine 34 form a core 44 of the engine 10, which produces combustion gases. The core 44 is surrounded by a core case 46, which can be coupled to the fan case 40.

[0044] An HP shaft or spool 48 disposed coaxially about the engine centerline 12 of the engine 10 drivingly couples the HP turbine 34 to the HP compressor 26. An LP shaft or spool 50 disposed coaxially about the engine centerline 12 of the engine 10 within the larger diameter annular HP spool 48 drivingly couples the LP turbine 36 to the LP compressor 24 and the fan 20. The spools 48, 50 are rotatable about the engine centerline 12 and are coupled to a plurality of rotatable elements that may collectively define a rotor 51.

[0045] The LP compressor 24 and the HP compressor 26 each include a plurality of compressor stages 52, 54 in which a set of compressor blades 56, 58 rotate relative to a set of corresponding static compressor vanes 60, 62 (also referred to as nozzles) to compress or pressurize a fluid flow through the stage. In a single compressor stage 52, 54, the plurality of compressor blades 56, 58 may be arranged in a ring and may extend radially outward from a blade platform to a blade tip relative to the engine centerline 12, with the corresponding static compressor vanes 60, 62 located upstream of and adjacent to the rotating blades 56, 58. It should be noted that Figure 1 The number of blades, buckets, and compressor stages shown in FIG. 5 are selected for illustration purposes only, and other numbers are possible.

[0046] Blades 56, 58 for a compressor stage may be mounted to disks 61 mounted to respective ones of the HP spool 48 and the LP spool 50, each stage having its own disk 61. Buckets 60, 62 for a compressor stage may be mounted to the core housing 46 in a circumferential arrangement.

[0047] The HP turbine 34 and the LP turbine 36 each include a plurality of turbine stages 64, 66 in which a set of turbine blades 68, 70 rotate relative to a set of corresponding static turbine vanes 72, 74 (also referred to as nozzles) to extract energy from the fluid flow through the stage. In a single turbine stage 64, 66, the plurality of turbine blades 68, 70 may be arranged in a ring and may extend radially outward from the blade platform to the blade tip relative to the engine centerline 12, while the corresponding static turbine vanes 72, 74 are located upstream and adjacent to the rotating turbine blades 68, 70. It should be noted that Figure 1 The number of blades, buckets, and turbine stages shown in FIG. 5 are selected for illustration purposes only, and other numbers are possible.

[0048] Turbine blades 68, 70 for the turbine stage may be mounted to disks 71 mounted to respective ones of the HP spool 48 and the LP spool 50, with each stage having a dedicated disk 71. Buckets 72, 74 for the compressor stage may be mounted to the core housing 46 in a circumferential arrangement.

[0049] Complementing the rotor portion, the stationary portion of the engine 10, such as the stationary blades 60, 62, 72, 74 in the compressor section 22 and the turbine section 32, are also individually or collectively referred to as stators 63. Therefore, the stator 63 may refer to the combination of non-rotating elements throughout the engine 10.

[0050] In operation, the airflow exiting the fan section 18 is split so that a portion of the airflow is directed into the LP compressor 24, which then supplies pressurized air 76 to the HP compressor 26, which further pressurizes the air. The pressurized air 76 from the HP compressor 26 is mixed with fuel and ignited in the combustor 30, thereby producing combustion gases. Some work is extracted from these gases by the HP turbine 34 that drives the HP compressor 26. The combustion gases are exhausted into the LP turbine 36, which extracts additional work to drive the LP compressor 24, and the exhaust gases are ultimately exhausted from the engine 10 via the exhaust section 38. The drive of the LP turbine 36 drives the LP spool 50 to rotate the fan 20 and the LP compressor 24.

[0051] A portion of the pressurized air flow 76 may be extracted from the compressor section 22 as bleed air 77. The bleed air 77 may be extracted from the pressurized air flow 76 and provided to engine components that require cooling. The temperature of the pressurized air flow 76 entering the combustor 30 is significantly increased. Therefore, the cooling provided by the bleed air 77 is necessary for operating such engine components in an elevated temperature environment.

[0052] The remainder of the airflow 78 bypasses the LP compressor 24 and the engine core 44 and exits the engine assembly 10 through the fixed vane rows, and more specifically, an exit guide vane assembly 80 including a plurality of airfoil guide vanes 82 located at the fan exhaust side 84. More specifically, a circumferential row of radially extending airfoil guide vanes 82 is used adjacent the fan section 18 to exert some directional control on the airflow 78.

[0053] Some of the air supplied by the fan 20 may bypass the engine core 44 and be used to cool portions of the engine 10, particularly the hot portions, and / or to cool or power other aspects of the aircraft. In the context of a turbine engine, the hot portions of the engine are generally downstream of the combustor 30, particularly the turbine section 32, with the HP turbine 34 being the hottest portion as it is located directly downstream of the combustion section 28. Other sources of cooling fluid may be, but are not limited to, fluid exhausted from the LP compressor 24 or the HP compressor 26.

[0054] Figure 2 is a perspective view of an engine component in the form of a turbine blade assembly 86 having Figure 1 1. Turbine blade 70 of engine 10. Alternatively, in non-limiting examples, the engine component may be a bucket, a strut, a service duct, a shroud, or a combustion liner, or any other engine component that may require or utilize a cooling passage.

[0055] The turbine blade assembly 86 includes a dovetail 90 and an airfoil 92. The airfoil 92 extends between a tip 94 and a root 96 to define a span direction 97. The airfoil 92 is mounted to the dovetail 90 on a platform 98 at the root 96. When a plurality of airfoils are arranged circumferentially in a side-by-side relationship, the platform 98 helps to radially contain the mainstream airflow of the turbine engine and form a radial inner wall of the annulus through which the air flows. The dovetail 90 can be configured to be mounted to the turbine rotor disk 71 on the engine 10. The dovetail 90 also includes at least one inlet passage 100 extending through the dovetail 90 to provide internal fluid communication with the airfoil 92.

[0056] The airfoil 92 includes a concave pressure side 110 and a convex suction side 112 that are joined together to define an airfoil cross-sectional shape of the airfoil 92, which extends between a leading edge 114 and a trailing edge 116 to define a chord-wise direction 115. The periphery of the airfoil 92 is bounded by an outer wall 118, which also defines the pressure side 110 and the suction side 112. The interior 102 of the airfoil 92 may include at least one cooling supply duct 104, as shown in dashed lines. The cooling supply duct 104 may be fluidly coupled to the inlet passage 100. At least one cooling hole 120 may be positioned along any portion of the outer wall 118, including along the leading edge 114 and the trailing edge 116 as shown. A transverse direction 117, which is perpendicular to both the spanwise direction 97 and the chord-wise direction 115, extends generally into the page.

[0057] At least one cooling hole 120 may pass through a substrate, which is illustratively the outer wall 118. However, it should be understood that the substrate may be any wall within the engine 10, including but not limited to an inner wall, a tip wall, or a combustion liner wall. The structural segment 122 may be disposed within a wall gap 124 formed within the outer wall 118.

[0058] The materials used to form the substrate and structural segments may include, but are not limited to, steel, refractory metals such as titanium, or superalloys based on nickel, cobalt or iron, and ceramic matrix composites. In non-limiting examples, the substrate and structural segments may be formed by a variety of methods, including additive manufacturing, casting, electroforming, or direct metal laser melting. As used herein, an "additive manufacturing" component will refer to a component formed by an additive manufacturing (AM) process, in which the component is built layer by layer by continuous deposition of material. AM is a suitable name for describing a technology that builds 3D objects by adding layers of materials (whether the material is plastic, ceramic or metal). AM technology can utilize computers, 3D modeling software (computer-aided design or CAD), machine equipment, and layered materials. Once a CAD sketch is generated, the AM equipment can read the data from the CAD file and place or add continuous layers of liquid, powder, sheet or other materials in a layered manner to manufacture a 3D object. It should be understood that the term "additive manufacturing" covers many technologies, including subsets such as 3D printing, rapid prototyping (RP), direct digital manufacturing (DDM), layered manufacturing, and additive manufacturing. Non-limiting examples of additive manufacturing that can be used to form additively manufactured parts include powder bed fusion, photopolymerization, binder jetting, material extrusion, directed energy deposition, material jetting, or sheet lamination. It is also contemplated that the processes used may include printing a negative of the part through refractory metals, ceramics, or printing plastics and then using the negative to cast the part.

[0059] Figure 3 is along Figure 2 The cross section taken along line III-III of FIG. 7 more clearly shows the wall gap 124. The turbine blade 70 may also include an inner wall 126 located within the interior and spaced apart from the outer wall 118 to define the wall gap 124. It is contemplated that the inner wall 126 and the outer wall 118 may contact or abut each other to form a solid wall portion 119, as shown near the leading edge 114. Additionally or alternatively, the inner wall 126 and the outer wall 118 may be spaced apart so that the wall gap 124 remains around the entire airfoil 92. The structural segment 122 includes a plurality of structural elements 128 extending between the outer wall 118 and the inner wall 126 and oriented at a structural element angle (α), which is an acute angle relative to the inner surface 130 of the outer wall 118 or the inner surface 132 of the inner wall 126. Although shown in the form of pins, the plurality of structural elements 128 may take any form or shape to form the structural segment 122, as a non-limiting example, a truss or web system within the wall gap 124. The structural elements 128 as described herein may be fins, pins, protrusions, turbulators, or any other suitable form or shape. It will be appreciated that the inner wall 126 faces the cooling flow C while the outer wall 118 faces the hot gas flow H.

[0060] Figure 4 1 is an enlarged schematic diagram of a portion of a structural segment 122. The structural segment 122 is more clearly shown with a structural element 128 extending between the outer wall 118 and the inner wall 126. The structural element angle (α) is defined as the acute angle between the inner surface 130 and the centerline of the structural element 128 shown in dashed lines. The structural element angle (α) is measured between the structural element 128 and the inner surface 130 of the outer wall 118.

[0061] The outer wall 118 and the inner wall 126 are made of the same material, so the crystallographic orientation 134 of the outer wall 118 and the inner wall 126 is the same. The crystallographic orientation 134 reflects the stress / strain properties of the material forming the outer wall 118 and the inner wall 126. The uniformity of the crystallographic orientation 134 relative to the random distribution depends on the percentage of crystals having a preferred orientation, which is at least partially represented by the grain angle (θ). It is generally assumed that the structural element angle (α) is not equal to the grain angle (θ). An important aspect disclosed herein involves evaluating the difference between the structural element angle (α) and the grain angle (θ) or considering the position of one angle relative to another angle by non-limiting examples, iterating until the ideal or optimal difference between the angles is found.

[0062] Steering Figure 5 , a schematic perspective view of an enlarged portion of the structural segment 122 is shown in 3D to more clearly show the crystallographic orientation 134 represented by the grain angle (θ), and the structural element angle (α) as the acute angle measured between the structural element 128 and the inner surface 130 of the outer wall 118. Figure 5 As shown, these angles are measured relative to the corresponding surfaces. The orientation and placement of the structural element 128 affects the stiffness of the structural segment 122. As a non-limiting example, the second structural element 129 is shown as extending vertically between the inner wall 118 and the outer wall 126. When the structural element angle (α) approaches 90°, such as the angle (α) of the second structural element 129, ┴ ), it will be appreciated that the structural segment 122 as a whole becomes stiffer in the transverse direction 117.

[0063] As a non-limiting example of a turbine blade 70, the baseline blade 142 is Fig. 6A 142 is an engine component having known characteristics - thermal, aerodynamic, internal fluid flow and structural dynamics. At least a portion 136 of the baseline blade 142 may be represented by a computer model. It should be understood that while only a portion of the baseline blade 142 is represented in portion 136, portion 136 may be the entire baseline blade 142.

[0064] Steering Figure 6B, portion 136 may be modeled as a cantilever beam and is referred to herein as a baseline plate portion 144. Baseline plate portion 144 is a mathematical model (e.g., a finite element model) of portion 136 that may represent the entirety of baseline blade 142 and is configured to model the same structural dynamic response characteristics as baseline blade 142.

[0065] Steering Figure 6C , shows a Campbell plot of a baseline plate portion 144 having the same frequency response characteristics as the baseline blade 142. The method includes determining a set of baseline frequencies or modal frequencies (f=1, 2, 3, 4, etc.) of the baseline blade 142. Figure 6C The modal frequencies identified in (f=1, 2, 3, 4, etc.) are represented by the y-axis. The engine 10 is operated at various speeds (ground idle (GI), flight idle (FI), approach (AP), cruise (CR), and takeoff (TO)) represented by the x-axis. The diagonal lines represent the various stages A, B, C, D within the engine, which may produce wakes that affect the response of the baseline blade 142, represented by the participating mode shapes and corresponding modal frequencies. Preferably, as shown in the figure, the three lines do not intersect at any single point, as this will produce undesirable vibration amplification.

[0066] Fig. 7A A modified blade 148 is schematically shown, modified to include a modified structural segment 122a. If the modified blade 148 were manufactured and subjected to physical testing, the modified blade 148 would represent a modified baseline blade.

[0067] Figure 7B is a schematic diagram of a portion 136 of a modified blade 148 in the form of a modified plate portion 146 having a modified structural segment 122a. Rather than physically testing the modified blade 148, the method includes modeling the modified plate portion 146 using the modified structural segment 122a formed as described herein. During simulated operation, the modified plate portion 146 vibrates with the fixed end 138. The modified structural segment 122a schematically represents the modifications made to the baseline plate portion 144 to form the modified plate portion 146 to affect the thermal, fluid flow, or aerodynamic requirements of the turbine blade 70 in a positive manner. It should be understood that these modifications are made to the model, not the physical blade.

[0068] The modified structural segment 122a is included in the modified plate portion 146 as a means of evaluating the effect that the addition of the modified structural segment 122a will have on the modal characteristics of the modified blade 148, including its vibration response to external forces and related properties that are important to design objectives, including but not limited to cooling, fatigue resistance, and / or weight reduction.

[0069] Figure 7C1 . The method includes determining a set of modified modal frequencies (f=1a, 2a, 3a, 4a, etc.) associated with the modified plate portion 146 of the modified blade 148 during simulation operation. The set of baseline modal frequencies (f=1, 2, 3, 4, etc.) may be shifted to a set of modified modal frequencies (f=1a, 2a, 3a, 4a, etc.) by replacing the baseline plate portion 144 with the modified plate portion 146 (including the modified structural segment 122a). The method may include comparing the set of modified modal frequencies (f=1a, 2a, 3a, 4a, etc.) with the set of baseline modal frequencies (f=1, 2, 3, 4, etc.) to determine if the set of modified modal frequencies (f=1a, 2a, 3a, 4a, etc.) would result in a resonant condition in the modified blade 148 if used in the engine. As shown, this shifting results in the three lines (frequency, speed, and engine level) intersecting at one point, see point 150. In one possible scenario, the third test resonant frequency 3a, ground idle (GI), and engine stage (D) all intersect, which means that the vibration of the modified blade 148 may be amplified when idling on the ground.

[0070] Fig. 8A Schematically illustrated is a tuned blade 154 modified to include a tuned structural segment 122b disposed in portion 136 as previously shown. In the event that a set of modified modal frequencies results in a resonant condition, additional modeling iterations may occur. The tuned blade 154 may be modeled to exhibit the behavior of the blade 70 during normal operation of the turbine engine 10.

[0071] Figure 8B is a schematic diagram of a portion 136 of a tuning blade 154 in the form of a tuning plate portion 152 having a tuning structure segment 122b. Again, rather than performing physical testing on the tuning blade 154, the method includes modeling the tuning plate portion 152 using the tuning structure segment 122b formed as described herein.

[0072] The corresponding Campbell diagram for the tuning plate portion 152 is Figure 8B For example, previously Figure 7C As depicted at point 150 in FIG. 1 , the tuning plate portion 152 corresponds to a set of tuned modal frequencies (f=1b, 2b, 3b, 4b, etc.), expressed as a set of frequencies that avoid overlap where all three curves intersect.

[0073] To mitigate the vibration response to engine conditions while incorporating desired thermal, fluid flow, or aerodynamic changes to the turbine blade 70 (in one example), the method includes comparing a set of modified modal frequencies (f=1a, 2a, 3a, 4a, etc.) to a set of baseline modal frequencies (f=1, 2, 3, 4, etc.). The tuned structural segment 122b may be developed by adjusting one or more structural or performance attributes. As non-limiting examples, these structural or performance attributes may be adjusted in the wall gap 124 and may include a structural element angle (α) and a volume fraction (v F ). Volume fraction (v F ) is a numerical value associated with the amount of space occupied by structural element 128 in wall gap 124. The volume fraction of solid wall gaps or substantially no wall gaps is equal to 1 (v F =1). As one or more of these variables are modified, the set of modified modal frequencies (f=1a, 2a, 3a, 4a, etc.) associated with the modified plate portion 146 changes to form a set of tuned modal frequencies (f=1b, 2b, 3b, 4b, etc.) that is different from the set of modified modal frequencies (f=1a, 2a, 3a, 4a, etc.). It is contemplated that the set of modified modal frequencies (f=1a, 2a, 3a, 4a, etc.) and the set of tuned modal frequencies (f=1b, 2b, 3b, 4b, etc.) are different from each other. However, in some exemplary cases, the set of modified modal frequencies (f=1a, 2a, 3a, 4a, etc.) and the set of tuned modal frequencies (f=1b, 2b, 3b, 4b, etc.) can be similar or even the same, in which case the modified structure segment 122a and the tuned structure segment 122b can be considered the same.

[0074] Once adjusted, the blade 140 is tested, by way of non-limiting example, Fig. 8A The test blade 154 shown in FIG. 1 is formed with the physical structure segment 122 to match the tuning structure segment 122b. It should be understood that the test blade 140 can also be a modified blade 148, depending on which model avoids the problem caused by Figure 7C The overlap shown at point 50 in FIG. 14A and FIG. 15B , while retaining the desired thermal, airflow and aerodynamic characteristics of the modified blade. Physical testing can now be performed. The method described herein narrows the blade possibilities to a more limited category worth testing, thereby saving considerable cost and time.

[0075] Fig. 92 is a flow chart of another method 200 for forming a test engine component by a non-limiting example test blade 140, for manufacturing a turbine blade 70 as described herein. The method 200 includes modeling a plate portion at 202, as a non-limiting example, a modified plate portion 146 as described herein. The method 200 includes calculating a frequency factor (Ff) associated with the modified plate portion 146 at 204. The modal frequency (f) of the cantilever beam can be calculated as follows:

[0076]

[0077] where the variables are a constant (c) associated with the modal frequency (1, 2, 3, etc.), (L) is the length, (ρ) is the mass density, (E) is the elastic modulus, and the cross-sectional moment of inertia (I) and area (A).

[0078] Ideally, an optimal combination of these values ​​is embodied in a structural segment, such as a turbine blade in the disclosed embodiments, which achieves a desired tuning characteristic for a given performance criterion (i.e., size, aerodynamics, cooling, etc.). The optimal frequency response of the structural segment is selected among candidate structural segments, where the candidate structural segments are distinguished from each other by differences in one or more of the calculated values ​​of E, I, and A.

[0079] It has unexpectedly been discovered that parameters can be defined and used in such a manner to identify structural characteristics for achieving the objectives described above in an efficient and useful manner such that a limited number of choices are found to reflect acceptable trade-offs between competing requirements for structural components, as will be understood upon practice as described.

[0080] This parameter is called the frequency factor (Ff):

[0081]

[0082] The calculated modulus (E') is the effective modulus (E eff ) and the baseline modulus (E associated with the baseline plate portion 144 o ) ratio. For anisotropic materials, E o is considered to be the effective or equivalent isotropic modulus. The calculated moment of inertia (I') is the effective moment of inertia (I') associated with the modified plate portion 146. eff ) and the moment of inertia (I o ) ratio. And the calculated area (A') is the effective area (A) with the modified plate portion 146 eff ) and the baseline area (A o ) ratio.

[0083] Reference again Fig. 9 , the method 200 may include determining each desired value (E', I', A') associated with a plate portion, as a non-limiting example, modifying the plate portion 146. It should be understood that the effective variable (E eff ,I eff , A eff ) can be changed according to different board sections, and the modification board section 146 or tuning board section 152 is used to determine each variable.

[0084]

[0085] Single crystal materials are anisotropic in nature, meaning they have different properties depending on the crystal orientation. eff ), see equation (1) below, for the structure, one must consider the orientation of the grains and how the structure is defined relative to that orientation.

[0086] Equation (1): E eff =[E min +(E max -E min )(sin(|α|)-sin(|θ|)](1-v F )+E o v F

[0087] In order to calculate the effective modulus (E eff ), it is necessary to calculate the modulus of the plate around the structural segment (E o ), which is similar to the modulus (E o ) are the same. Recall that, as mentioned earlier, these equations reflect the average or effective isotropic modulus equivalent of the anisotropic material. The minimum elastic modulus (E min ) and maximum elastic modulus (E max ) depend on the grain orientation and represent the highest modulus direction and the lowest modulus direction, respectively, for an anisotropic material. The resulting equation is a combination of two parts: the elastic modulus of the "structural segment" and the elastic modulus of the plate to form the overall effective modulus, which can then be derived. The effective modulus (E eff ) is affected by the orientation of the pins, the structural element angle (α) relative to the grain orientation, the grain angle (θ), the grain angle (θ) itself, and the “number” of pins relative to the overall size of the structure, the volume fraction (v F ) is affected by the effective modulus of the plate (E eff ) is determined by the plate modulus (E o ) and the “number” of plates relative to the size of the structure, also using the volume fraction (v F )calculate.

[0088] Thus, by considering the difference between the structural element angle (α) and the grain angle (θ), the calculated modulus (E') is determined by a relationship based on a comparison of the grain orientation reflected in the grain angle θ with the structural element orientation reflected in the structural element angle (α). It is contemplated that the absolute value of the difference between the structural element angle (α) and the grain angle (θ) is between 45 degrees and 90 degrees. It is further contemplated that the difference between the structural element angle (α) and the grain angle (θ) is between 10 degrees and 90 degrees. Furthermore, the relationship used to determine the calculated modulus is based on a volume fraction (v) associated with the number of structural elements 128 filling the wall gap. F ).

[0089] Changing anything associated with the structural element 128 described herein will affect the volume fraction (v F ), which in turn affects the calculated area (A') and the calculated moment of inertia (I'), making the total amount of the frequency factor (Ff) important in narrowing down the viable choices for manufacturing a blade or other engine component. When considering only the calculated modulus (E'), other factors associated with affecting the frequency of the modeled structure are ignored. By considering all factors, the calculated frequency factor (Ff) eliminates poor choices for manufacturing a blade.

[0090] The calculated moment of inertia (I) and the calculated area (A) may be determined using solid 3D modeling software based on known variables. The known variables for calculating the area (A) may include the volume fraction (v) associated with the structural element 128. F ), where for the base plate portion 144 (v F =1), a base dimension (b) associated with the plate portions 144, 146, 152 discussed herein, and a height dimension (h) associated with the thickness of the walls 118, 126 and the wall gap 124 of each plate portion 144, 146, 152 discussed herein. The calculated moment of inertia (I) is determined at least in part by the base dimension (b) and the height dimension (h).

[0091] At 206, the method includes adjusting the wall gap 124 or at least one variable (the wall gap 124, the structural angle (θ), or the volume fraction (v F)) until the frequency factor is between 1 and 1.4 to define a tuning plate portion, such as the tuning plate portion 152 described herein, as a non-limiting example. The frequency factor (Ff) is unique to each structural segment 122, and therefore unique to any individual plate portion 144, 146, 152 described herein. When (Ff=1) there is no wall gap 124, the frequency factor (Ff) associated with a solid blade plate or the baseline plate portion 144 described herein will be effectively equal to 1. When (Ff=1.4) there is a wall gap 124 but no structural element 128, the introduction of the wall gap 124 alone will effectively increase the frequency factor to about 1.4. To increase stiffness, the structural element 128 is added. To prevent the three lines in the Campbell diagram from intersecting, the structural element orientation, and more specifically the structural element angle α, can be adjusted or tuned so that the tuning plate portion 152 with the tuning structural segment 122b has a frequency factor where 1.0<Ff<1.4, and more preferably 1.03<Ff<1.25.

[0092] At 208 , a test engine component, such as the test blade 140 described herein as a non-limiting example, is formed with a trim plate portion, such as the modified or trim plate portions 146 , 152 described herein.

[0093] It should be understood that the entirety of the turbine blade 70 as described herein may be considered as a single plate portion. Further, it should be understood that the turbine blade 70 as described herein may be divided into a plurality of plate portions as described herein, wherein a frequency factor (Ff) of each plate portion is determined in order to determine a total frequency factor (TFf) of the entire turbine blade 70. It is further contemplated that the total frequency factor (TFf) is also within the range of 1.0<TFf<1.4, more preferably 1.03<TFf<1.25.

[0094] It should be further understood that, by way of non-limiting example, the modified plate portion 146 and the tuned plate portion 152 may be identical, with the frequency factor (Ff) being between 1.0 and 1.4, and the lines on the Campbell plot not intersecting at any single point prior to the adjustment step.

[0095] Steering Fig.10, an exemplary structural segment 222 is shown. The structural segment 222 may include a truss 250 formed of four structural elements 228 located within a wall gap 224 formed between an inner wall (removed for clarity) and an outer wall 218. The four structural elements 228 form a pyramidal shape 252 having apexes 254 and bases 256 such that the pyramidal shapes 252 alternate in orientation such that the apexes 254 alternate between an inner surface 232 formed on the inner wall (removed for clarity) and an inner surface 230 of the outer wall 218. The base 256 includes four corners, each corner being a vertex 254 of an adjacent pyramidal shape 252. For the plate portion in which the structural segment 222 is formed, the structural segment 222 produces a frequency factor, where 1.0<Ff<1.4. Although illustrated as intersecting at either the inner or outer wall 218, it should be understood that the structural elements 228 may intersect at any point in the wall gap 224, wherein the apex 254 is spaced from both the inner surface 230 of the outer wall 218 and the inner surface 232 of the inner wall. In other words, the structural elements may be formed into an "X" shape. It should be understood that the exemplary structural segment 222 is for purposes of illustration and is not meant to be limiting, as the structural elements 228 may be oriented in any manner to create a complex shape with multiple intersections.

[0096] Steering Fig.11 , an exemplary structural segment 322 is shown. The structural segment 322 includes a first group of structural elements 360 and a second group of structural elements 362, which are located in the wall gap 224 formed between the inner wall (removed for clarity) and the outer wall 318. The first group of structural elements 360 is formed in a zigzag shape, wherein each structural element 328 extends from the inner surface 332 of the inner wall (removed for clarity) to the inner surface 330 of the outer wall 318 along at least one line extending in a first direction 364. As shown, the first group of structural elements 360 can be a plurality of groups of structural elements 360 spaced apart from each other along a plurality of lines extending in the first direction 364. The second group of structural elements 362 is formed in a zigzag shape, wherein each structural element 328 extends from the inner surface 332 of the inner wall (removed for clarity) to the inner surface 330 of the outer wall 318 along at least one line extending in a second direction 366. As shown, the second set of structural elements 362 can be multiple sets of structural elements 362 that are spaced apart from each other along multiple lines extending in a second direction 366. The first set of structural elements 360 and the second set of structural elements 362 intersect at intersections 368 along the inner surface 332 of the inner wall. It should be understood that multiple intersections 368 are contemplated as shown. Although shown as intersecting at the inner wall or the outer wall 318, it should be understood that the structural elements 328 can intersect at any point in the wall gap 324 where the apex 354 is spaced apart from both the inner surface 330 of the outer wall 318 and the inner surface 332 of the inner wall. In other words, the structural elements can be made into an "X" shape.

[0097] As previously described, the turbine blade 70 can be divided into multiple plate portions. It should also be understood that each plate portion can include structural elements oriented at the same structural element angle (α), or each structural element can be oriented at various structural element angles that are not equal to each other. Mathematical modeling, i.e., integration of the plate portion as a whole, can take into account the varying values ​​of the structural element angle (α) as described herein. Similarly, it should be understood that the grain angle (θ) described herein can also vary as the material changes. Therefore, it should be understood that the exemplary structural segments 222, 322, although shown as having a single structural element angle (α), the value of the angle can vary or be the same.

[0098] Benefits associated with the apparatus and methods described herein include providing new tools for engineers / designers. Using the methods described herein, engineers can now use the structural element angle relative to the grain orientation, or grain angle (θ) described herein, to influence the overall frequency of the structure.

[0099] Additional benefits associated with the structural segments as described herein include reducing the weight of the blade while maintaining the structural integrity and natural resonance of the blade as described herein. Tuning enables multi-dimensional changes in various parts of the blade. Benefits also include structural benefits, stiffness benefits, and stiffness tuning. Stiffness tuning is particularly important for turbine blades. High cycle fatigue and its monitoring are critical. This requires a compromise between adding more weight and moving structural elements and other general items that make the overall efficiency of the blade design less efficient. The structural segments designed as described herein can also enable customization of blade weight, improve structural integrity during blade manufacturing, and / or help manage thermal stresses during blade manufacturing.

[0100] Cooling benefits may also result from the structural segments described herein, including but not limited to conduction benefits between the inner and outer surfaces of the wall. The structural segments may also enhance heat transfer in the presence of a cooling fluid.

[0101] Additive manufacturing techniques or other advanced casting manufacturing techniques (such as investment casting and 3-D printing as well as laser drilling and EDM drilling) can be used to manufacture the structural segments as described herein. Available techniques provide cost benefits as well as the other benefits described. It should be understood that other methods of forming the cooling circuits and cooling holes described herein are also contemplated and that the disclosed methods are for exemplary purposes only.

[0102] It should be understood that application of the disclosed design is not limited to turbine engines having fan and supercharger sections, but is also applicable to turbojets and turboprops.

[0103] To the extent not yet described, the different features and structures of the various embodiments may be used in combination or in place of one another as desired. A feature not shown in all embodiments is not meant to be interpreted as not being so shown, but is done so for the sake of brevity of description. Therefore, the various features of the different embodiments may be mixed and matched as desired to form new embodiments, whether or not the new embodiments are explicitly described. All combinations or permutations of the features described herein are encompassed by the present disclosure.

[0104] This written description uses examples to describe the disclosed aspects described herein, including the best mode, and also to enable those skilled in the art to practice the disclosed aspects, including making and using any device or system and performing any incorporated methods. The patentable scope of the aspects of the present disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. These other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ substantially from the literal language of the claims.

[0105] The various features, aspects and advantages of the present disclosure may also be embodied in the following technical solutions defined by the clauses:

[0106] An engine component for a turbine engine, the engine component comprising: a wall, the wall comprising an inner wall and an outer wall, the outer wall being spaced apart from the inner wall to define a wall gap and bound an interior; a structural segment, the structural segment defining a portion of the wall, the structural segment comprising at least one structural element, the at least one structural element being disposed between the inner wall and the outer wall in an orientation defined by a structural element angle; wherein a frequency factor determined by a modulus, an area, and a moment of inertia each associated with the structural segment is between 1 and 1.4.

[0107] An engine component as described in any preceding clause, wherein the inner wall and the outer wall are formed of a material having a crystallographic orientation defined at least in part by a grain angle, and the structural element angle and the grain angle form a relationship that determines the modulus.

[0108] An engine component according to any preceding clause, wherein at least one structural element has a volume fraction determined by the amount of the structural element filling the space in the wall gap, and the volume fraction further affects the relationship determining the modulus.

[0109] An engine component as described in any preceding clause, wherein the plate portion defines a base and a height forming a relationship defining a moment of inertia, and using the volume fraction, the base and the height forming a relationship defining an area.

[0110] An engine component according to any preceding clause, wherein the structural segment comprises a truss formed from at least four structural elements to define a pyramidal shape.

[0111] The engine component of claim 5, wherein the pyramidal shapes alternate in orientation within the wall gap.

[0112] An engine component as described in any preceding clause, wherein the structural segment comprises a first set of structural elements oriented in a first direction and a second set of structural elements oriented in a second direction different from the first direction.

[0113] An engine component as claimed in any preceding clause, wherein the first set of structural elements and the second set of structural elements intersect at an intersection along an inner surface of one of the inner wall or the outer wall.

[0114] A method of forming a test engine component for manufacturing an engine component, the method comprising: modeling a plate portion, the plate portion comprising an outer wall, an inner wall, and a structural segment, the inner wall being spaced apart from the outer wall to define a wall gap, the structural segment being formed within the wall gap, the structural segment comprising at least one structural element, the at least one structural element extending between the inner wall and the outer wall, the structural element defining at least one variable; calculating a frequency factor determined by a modulus, an area, and a moment of inertia associated with the plate portion; and adjusting at least one of the wall gap or at least one variable until the frequency factor is between 1.0 and 1.4 to define an adjusted plate portion; forming the test engine component having the adjusted plate portion.

[0115] A method as in any preceding clause, wherein adjusting at least one variable comprises adjusting a structural element angle, the structural element angle defining an orientation of at least one structural element extending between the inner wall and the outer wall.

[0116] A method as in any preceding clause, further comprising determining a grain angle, the grain angle defining at least a portion of a crystallographic orientation of a material forming the inner wall and the outer wall.

[0117] A method as in any preceding clause, further comprising determining the modulus, wherein at least one structural element has a volume fraction defining a portion of the space in the wall interstitial filled by the at least one structural element, and the volume fraction, the structural element angle, and the grain angle form a relationship that determines the modulus.

[0118] A method according to any preceding clause, further comprising determining an area, wherein at least one structural element has a volume fraction defining a portion of a space in a wall gap filled by the at least one structural element, the plate portion defines a base and a height, and the volume fraction, base and height form a relationship that determines the area.

[0119] A method as in any preceding clause, further comprising determining a moment of inertia, wherein the plate portion defines a base and a height, and the base and the height form a relationship that determines the moment of inertia.

[0120] The method of any preceding clause, further comprising determining during operation a set of modified resonant frequencies for an engine component having a modified plate portion and determining a set of baseline resonant frequencies associated with an engine component without a modified plate portion, and comparing the set of modified resonant frequencies to the set of baseline resonant frequencies and adjusting at least one of the wall clearance or the at least one variable until the set of modified resonant frequencies equals the set of baseline resonant frequencies.

[0121] A method of forming a test blade for manufacturing a blade, the method comprising: modeling a baseline blade to define a baseline plate portion; during a simulation operation, determining a set of baseline modal frequencies for the baseline plate portion; modeling a modified blade to define a modified plate portion, the modified plate portion having an outer wall, an inner wall spaced from the outer wall to define a wall gap, and a structural segment defining a portion of the wall, at least one structural element being disposed within the wall gap; during a simulation operation, determining a set of modified modal frequencies for the modified blade; comparing the set of modified modal frequencies to a set of baseline modal frequencies; in the event that the set of modified modal frequencies results in a resonant condition in the modified blade, adjusting the structural segment to define a tuned structural segment, and modeling the tuned blade to define a tuned plate portion having the tuned structural segment; and forming a test blade having a structural segment matching one of the modified plate portion or the tuned plate portion.

[0122] A method as in any preceding clause, wherein adjusting the structural segment comprises adjusting at least one variable, the at least one variable comprising a structural element angle defining an orientation of at least one structural element within the wall gap.

[0123] A method as in any preceding clause, wherein adjusting at least one variable comprises adjusting a volume fraction of a portion of the space in the wall gap defined by the at least one structural element.

[0124] A method as in any preceding clause, further comprising calculating a frequency factor associated with the modified plate portion.

[0125] A method as in any preceding clause, wherein adjusting the structure segment comprises adjusting at least one variable associated with the structure segment until the frequency factor is between 1.0 and 1.4.

Claims

1. An engine component for a turbine engine, characterized in that: The engine components include: a wall, the wall comprising an inner wall and an outer wall, the outer wall being spaced apart from the inner wall to define a wall gap and bound an interior; a structural segment defining a portion of the wall, the structural segment comprising at least one structural element disposed between the inner wall and the outer wall in an orientation defined by a structural element angle; and The frequency factor, determined by the modulus, area and moment of inertia respectively associated with the structural segment, is between 1 and 1.

4.

2. The engine component according to claim 1, characterized in that Wherein the inner wall and the outer wall are formed of a material having a crystallographic orientation defined at least in part by a grain angle, and the structural element angle and the grain angle form a relationship that determines the modulus.

3. The engine component according to claim 1, characterized in that Wherein the at least one structural element has a volume fraction determined by the amount of the structural element filling the space in the wall gap, and the volume fraction further affects the determination of the modulus.

4. The engine component according to claim 3, characterized in that Wherein the structural segment defines a base dimension and a height dimension that determine the moment of inertia, and the base dimension and the height dimension determine the area using the volume fraction.

5. The engine component according to claim 1, characterized in that Wherein the structural segment comprises a truss formed from at least four structural elements to define a pyramidal shape.

6. The engine component according to claim 5, characterized in that Wherein the pyramid shapes alternate in orientation.

7. The engine component according to claim 1, characterized in that The structural segment comprises a first set of structural elements extending in a first direction and a second set of structural elements extending in a second direction different from the first direction.

8. The engine component according to claim 7, characterized in that The first group of structural elements and the second group of structural elements intersect at an intersection along an inner surface of one of the inner wall or the outer wall.

9. A blade for a turbine engine, characterized in that: The blade comprises: a wall having an inner wall and an outer wall, the outer wall being spaced apart from the inner wall to define a wall gap, and at least one structural element disposed between the inner wall and the outer wall in an orientation defined by a structural element angle; the wall having a modulus (E'), an area (A'), and a moment of inertia (I'); and wherein the blade has a frequency factor determined by the modulus, the area and the moment of inertia And wherein the frequency factor is between 1 and 1.

4.

10. A test blade for a turbine engine, characterized in that: The test blade comprises: an outer wall, an inner wall, and a structural element, the inner wall being spaced apart from the outer wall to define a wall gap, the structural element being disposed within the wall gap at an orientation defined by a structural element angle, the structural element angle determining a frequency factor associated with the test blade; and The test blades therein have a frequency factor between 1 and 1.4, wherein a frequency factor equal to 1 is associated with a solid wall without wall gaps and a frequency factor equal to 1.4 is associated with a wall gap without structural elements.

Images