Structural Crack Monitoring' title='Structural Crack Monitoring' />Steam Turbine Blade Reverse Engineering, Upgrade, and Structural Design. Steam turbine blade cracking often suggests the need for an upgraded blade design. Short periods of rapid crack growth when the temperature 600C during the cleaning cycles. Long periods of very slow crack growth at the normal reactor. CENTER FOR STRUCTURAL DURABILITY Causes Cures for Cracking of Concrete Barriers ii All the survey respondents indicated that premature distress is observed on. Home Coal Steam Turbine Blade Reverse Engineering, Upgrade, and Structural Design Steam Turbine Blade Reverse Engineering, Upgrade, and Structural Design. Follow the process of reversing engineering a failed blade to produce a more reliable and efficient design. Blade reverse engineering is widely recognized as a crucial step in the product design cycle. Blade surface reconstruction is an iterative process to develop mathematical models from existing physical objects for finite element analysis FEA, computational fluid dynamics, and rapid prototyping in order to reduce product design lead time. In this process, precise data point measurement is important to create a valid shape. Due to the complexity of blade shape, the resultant model geometry change can lead to a large alteration in turbine performance see sidebar. Therefore, blade shape control is critical in the design process. In essence, the blade is a complex cantilever beam, and generating an accurate simulation result makes turbine blade analysis challenging. Finite element analysis is the accepted tool for turbine blade structural analysis. Both the model development upgrades and analysis will be discussed. Turbine Blade Design Fundamentals. Turbine blade design involves blade solid model development, thermo aerodynamics, and structural mechanics disciplines. Obzory/BIM/2016/33/AS.png' alt='Structural Crack Monitoring' title='Structural Crack Monitoring' />Encardio Rite is a leading manufacturer and supplier of geotechnical instrumentation for civil engineering projects and ground water level monitoring with base at. Chartered Engineer Clive Richardson explores structural movement including the causes and outcomes of subsidence, settlement and other forms of movement as well as. The process of reverse engineering begins with determining the function of the machine part referred to as capturing design intent. The accuracy of reverse engineering is limited by the applied measurement and computer aided modeling techniques. A few of the major limitations are wear of the part numerical, sensing, and approximation errors and manufacturing methods. Goudy Trajan Regular Font here. In order to ensure and enhance blade efficiency, optimizing the shape design of rotating and stationary blades is essential. The necessary steps for turbine blade reverse engineering are similar to those used in a new product development practice Figure 1. The process for steam turbine blade design from concept to actual product is an iterative one that includes computer aided design CAD models, including blade surface for computer aided manufacturing, FEAand, if necessary, computational fluidized dynamics reliability performance analysis and design modification. The following case study presents an industrial application of an integrated reverse engineering approach to turbine blade design. Aldus Persuasion 3.0. The study describes a developed engineering approach to designing and upgrading a steam turbine blade from an existing part. Data Point, Surface, and Cross Section Generation. Turbine blades present challenges to manufacturers to produce and maintain the blades complex free form surfaces and seemingly convoluted shapes. Contact measuring devices cannot gather enough data points to create an accurate surface profile of the airfoils irregular shape. Laser scanning is the best measurement method to capture the turbine blades entire complex features. After scanning the blade from multiple perspectives, the points of cloud data are rotated into the same reference frame and assembled into an exact 3. D model of the scanned part. The data points for this case study were edited using Geomagic Studio software. Following that, the blades entire 3 D surface was generated in the same environment. A perfect CAD model is necessary for machining and FEA because turbine blades must be highly consistent in shape, weight, and geometry in order to avoid vibration and other performance impeding characteristics. The entire CAD model can be compared with the original part to ensure the models quality. The inspection for this case study was performed with Geomagic Qualify engineering software. Inspection of the model and the original part indicated very good agreement 0. Tenon Inspection, Analysis, and Installation. Quality inspection of the turbine shaft assembly extends to the wheel steeple and the blade in order to collect information about the parts structural integrity and to draw a conclusion about the repair process, which can include actual repair or redesign. In this case, nondestructive testing NDT of the blades tenon revealed that a crack had initiated at the root of the tenon radius area Figure 2. The crack in the area of the tenon root at the base of the existing blade probably was caused by an improper size root radius, which could initiate cracking after the riveting process. The cracks appear to propagate after every cycle of the turbine operation sequence. Analysis was needed to determine the crack initiation mechanism at the root of the tenon. A 2 D FEA indicated a distortion at the tenon root radius area after peening, as shown in Figure 3. Peening the tenon involves deliberate plastic deformation, making it easy to understand the importance of high ductility in the blade material. Low ductility may create serious problems during the peening process, including cracks and even fractures in the tenons. The most critical process is riveting the tenon to deform it into the classic river shape as part of the shroud attachment process without this step, the tenon could not be attached. Clearly, correct assembly of the shroud band segments and riveting of the tenons are critical to long term reliability. The accepted refurbishment technique for blade tenon assembly is to reattach or resecure the cover band. Weld repair for blades where the crack was detected is one technique that was applied for purposes of this case study. Additional use of under cover band brazing further increased security of the attachment. Remington Age By Serial Number. Shaft Steeple Inspection and Redesign. NDT of the steeple revealed that a crack initiated at the root of the steeple hooks radius areas and appeared in every hook. In order to modify the stress field at the cracked area of the steeple hooks, a fir tree steeple configuration was proposed at the joint between the turbine blade and the disk. This joint represents the most critical load path within that assembly. A fir tree hook blade configuration has been commonly implemented in turbines because this design can accommodate multiple areas of contact over large contact loads. Figure 5 displays the proposed fir tree blade steeple configuration as a possible repair solution. The new blade base design is shown in Figure 6. Design of the fir tree geometry was carried out using a commercially available CAD package. The model was defined parametrically in order to incorporate changes throughout the design optimization process. Every step of the modeling process was checked to make sure an adequate geometry could be produced otherwise, a geometry failure was a signal to the optimizer to cancel or modify the model and the analysis. The blade root and the disk steeple geometry were defined in the same way as the basic tooth, with further parameters and rules needed. Because the fir tree steeple cross sectional geometry is constant along the root center line, it is possible to assume that stress is present in two dimensions, although the load is actually in three dimensions. Nonetheless, it is still possible to assume that each section behaves essentially as a 2 D axial symmetric problem with different loading applied on the hooks. In order to verify the feasibility of the fir tree configuration, comprehensive 2 D axial symmetric steeple and 3 D blade FEAs were executed on the original and the updated fir tree region of the blade disk assembly.