Jet Engine Components Research Articles

Increased Cutting Conditions when Machining Heat-resistant Steel Using Indexable Inserts

The topic of the article is the increase of cutting conditions in the machining of heat-resistant steel using exchangeable inserts. The main part is the design of a new technology for machining one of the heat-resistant materials using replaceable inserts, including a discussion of any defects and economic evaluation. The aim is to reduce production costs and contribute to the elimination of production times. These modifications of technologies have a positive effect on the overall economy of produc-tion and the use of new methods in practice. Heat-resistant steels have found application in many branches of production, especially in the aerospace industry for jet engine components. Their specific properties need a more detailed examination of the optimal conditions for their processing.

Elastic properties of iron and tantalum at high pressure and temperature

Iron and tantalum have many important applications in tools, infrastructure, and electronics. In service, metallic parts can experience extreme stresses and temperatures (e.g., jet engine components, chemical processing equipment, supports for large structures), thus it is important to understand their elastic properties as a function of both pressure and temperature in order to allow engineers to appropriately design components using these materials. To determine these properties, we measured sound speeds and densities of Fe and Ta samples as a function of pressure and temperature. These measurements were performed in a large volume hydraulic pressure cell in situ at the Advanced Photon Source. Ultrasound time-of-flight was measured using the pulse-echo method and the sample dimensions were measured using x-ray radiography. x-ray diffraction was used to determine the sample densities. The longitudinal and shear sound speeds and the density measurements were combined to determine the bulk, Young’s, and shear moduli and Poisson’s ratio as pressure and temperature was changed. This talk will present these elastic properties as a function of pressure (up to 7 GPa) and temperature (up to 1000 °C). Finally, electron microscopy techniques will be discussed as a method of quantifying texture evolution during sample compression.

The assessment of the technical condition of SO-3 engine turbine blades using an impulse test

The paper presents the effects of the application of an experimental impulse test as a method of diagnosis of the technical condition of an SO-3 engine turbine blade fitted in a TS-11 Iskra aircraft. The aim of the test was to investigate the frequency characteristics of the blades and discuss differences between the frequency spectrum of the investigated component before and after its damage. The acoustic response measurements were performed to the signal generated by an impact hammer on the fully functional and intentionally damaged blades. The recorded signals were converted from the domain of time to the domain of frequency using the Fast Fourier Transform (FFT). The results of the FFT were the Frequency Response Functions (FRF) of the sound of the blades, based on which the statistical analysis of the resonance frequencies was carried out. The influence of the mechanical damage of the blade on the shape and characteristics of the frequency spectrum was confirmed, which substantiated the effectiveness of the impulse test in the diagnostic assessment of jet engine components.

Optimizing the fiber push‐out method to evaluate interfacial failure in SiC/BN/SiC ceramic matrix composites

AbstractThe investigation of several parameters during fiber push‐out micromechanical tests on the interfacial shear strength (ISS) of the BN interphase in SiCf/SiC ceramic matrix composites (CMC) was undertaken to optimize experimental work. The SiCf/SiC composites—candidate materials for jet engine components—were manufactured with varying fiber types and interlayer thicknesses. Experimental parameters explored included analyzing the effect of sample thickness on the success rate of micromechanical tests, the effect of fiber local environment whether at tow‐level (intra‐tow variability in ISS) or CMC architecture‐level (inter‐tow variability), the effect of nanoindenter flat‐punch tip size, and the effect of the interphase thickness itself. Over 1000 fiber push‐outs were performed and analyzed in this work—with data presented as cumulative distribution functions to compare and contrast samples. It was found that the ISS measured was strongly and statistically influenced by the underlying fiber roughness (interphase adherence), as well as its local fiber environment (e.g., number of nearest neighbors) only if the thickness of the interphase itself surpassed a threshold of 200 nm. Finally for thinner interphases, limited value was added to the CMC as the ISS measured was high and there was no effect from any local environment.

Combination of PIP and LSI processes for SiC/SiC ceramic matrix composites

Silicon carbide fiber-reinforced silicon carbide matrix composites (SiC/SiC CMCs) are promising candidates for hot gas components in jet engines. Three common manufacturing routes are chemical vapor infiltration, reactive melt infiltration (RMI) and polymer infiltration and pyrolysis (PIP). A combination of the processes seems attractive: the remaining porosity after PIP process can be closed by subsequent siliconization, resulting in a dense material. This work describes a new approach of a combined PIP and RMI process. SiC/SiC CMCs were manufactured by PIP process using Hi-Nicalon Type S fibers. An additional RMI was carried out after a reduced number of PIP cycles. Microstructure was examined via μCT, SEM and EDS. Bending strength was determined to 433 ​MPa; strain to failure was 0.60%. The overall processing time was reduced by 55% compared to standard PIP route. The hybrid material contained 70% less unreacted carbon than material produced by LSI process alone.

On the effect of the microstructure on the dynamic behaviour of Ti-6Al-4V

Aerospace components in jet engines need to outstand extreme conditions of high-temperatures and loads. Moreover, these components can sometimes undergo dynamic conditions if impact occurs during the flight. It is critical to understand the behaviour of aerospace alloys under these combined extreme conditions of high-temperature and dynamics loads. One of the most extended alloys used in the compressor and fan stages of commercial jet engines is Ti-6Al4V. The dynamic properties of Ti-6Al-4V are strongly dependent on the microstructure state and the temperature conditions. However, these dependencies are yet not fully understood. Moreover, this alloy can present a wide variety of microstructures depending on the component and manufacturing methods. In this work, we compare the response of five typical Ti-6Al-4V microstructures tested under static and dynamic conditions and different temperatures. The macroscopic response of the alloy is rationalised on the basis of its microstructural state using combined microscopy characterisation and computational modelling. To this end, computational plastic models are constructed and validated against experimental observations. In this way, the relationship between the mechanical properties of each microstructure and the temperature and strain rate conditions can be extracted to optimize the material state under specific dynamics in-service conditions.

Development of Energy Intensive Multifunction Cavitation Technology and Its Application to the Surface Modification of the Ni-Based Columnar Crystal Superalloy CM186LC

The present work demonstrates a technique for the hot forging of metal surfaces in water at 1000 °C or higher, termed energy-intensive multifunctional cavitation (EI-MFC). In this process, the energy of cavitation bubbles is maximized, following which these bubbles collide with the metal surface. This technique will be employed to improve the surface structure of CM186LC/DS, a Ni-based columnar crystalline superalloy used to manufacture the rotor blades of jet engines and gas turbines that are exposed to high-temperature oxidizing environments, with the aim of improving creep strength. EI-MFC processing induces compressive residual stress in the metal that prevents the occurrence of surface cracks and also increases surface hardness, improves corrosion resistance, and increases the coefficient of friction. The latter effect can enhance the adhesion of thermal barrier coatings applied to Ni-based superalloys by thermal spraying. The technology demonstrated herein can be applied to present-day jet engine and gas turbine components and also to the production of hydrogen combustion turbines operating at 1700 °C with higher combustion efficiency than the current 1500 °C class gas turbines. In addition, the high processing energy obtained using the EI-MFC technique has the potential to flatten rough surfaces resulting from the stacking pitches of various metals manufactured using three-dimensional printers, and so improve surface strength.

Design Space Exploration of a Jet Engine Component Using a Combined Object Model for Function and Geometry

The design of aircraft and engine components hinges on the use of computer aided design (CAD) models and the subsequent geometry-based analyses for evaluation of the quality of a concept. However, the generation (and variation) of CAD models to include radical or novel design solutions is a resource intense modelling effort. While approaches to automate the generation and variation of CAD models exist, they neglect the capture and representation of the product’s design rationale—what the product is supposed to do. The design space exploration approach Function and Geometry Exploration (FGE) aims to support the exploration of more functionally and geometrically different product concepts under consideration of not only geometrical, but also teleological aspects. The FGE approach has been presented and verified in a previous presentation. However, in order to contribute to engineering design practice, a design method needs to be validated through application in industrial practice. Hence, this publication reports from a study where the FGE approach has been applied by a design team of a Swedish aerospace manufacturers in a conceptual product development project. Conceptually different alternatives were identified in order to meet the expected functionality of a guide vane (GV). The FGE was introduced and applied in a series of workshops. Data was collected through participatory observation in the design teams by the researchers, as well as interviews and questionnaires. The results reveal the potential of the FGE approach as a design support to: (1) Represent and capture the design rationale and the design space; (2) capture, integrate and model novel solutions; and (3) provide support for the embodiment of novel concepts that would otherwise remain unexplored. In conclusion, the FGE method supports designers to articulate and link the design rationale, including functional requirements and alternative solutions, to geometrical features of the product concepts. The method supports the exploration of alternative solutions as well as functions. However, scalability and robustness of the generated CAD models remain subject to further research.

Abrasive water jet piercing of inclined holes on ceramic coated nickel superalloy: A preliminary study

Micro inclined holes are widely used as cooling holes in the jet engine and gas turbine components for its protection from a high temperature gas stream. Usually, these components were made of thermal barrier coated (TBC) nickel superalloy as which often high corrosion and thermal fatigue resistance. In this work, the small diameter cooling holes with different inclination angles were fabricated on TBC nickel superalloy using the Abrasive Water Jet (AWJ) through a piercing mode. Different holes were fabricated through the employment of different settings of AWJ operational parameters namely jet impingement angle, stand-off distance and abrasive mass flow rate. The effect of piercing parameters on machining time, hole entry diameter and surface morphology were examined. From the experimental results, it is confirmed that the inclined hole surfaces do not contain any cracks and delamination. However, the rough morphology i.e wear tracks and microchips was seen in the hole wall surfaces. The preliminary results confirmed that the AWJ has capable for the production of cooling holes than other processing techniques based on lesser machining time and satisfactory hole quality. Yet, the further investigations would be required for comprehensive study of hole geometrical and surface features, and optimization of it.

Film Cooling Experimental Study on Sinusoidal Corrugated Liner for Afterburner

Abstract The need of improved cooling effectiveness for hot components in jet engines has led to new designs of afterburner liners. In the present paper, experiments were performed to reveal the cooling characteristics and flow loss of various sinusoidal corrugated liners for an advanced afterburner. It is found that there are alternate high temperature and low temperature zones corresponding to the wave crests and troughs of the corrugated liner, respectively. Compared to the flat liner, the corrugated liner increases cooling effectiveness by 10 % at the blowing ratio of 0.5, by 4.5 % at the blowing ratio of 3.2. However, the difference in discharge coefficients for these two kinds of liners is only 4.3 %. The increased opening ratio of film holes from 1.42 % to 3.72 % for corrugated liners is able to improve the cooling effectiveness by 9.8 %. However, the discharge coefficient is decreased by 34.1 %. The augment of amplitude of liners can enhance the ram effect of cooling air, which has an advantage to increase the local blowing ratio, and to form good cooling film at the windward of wave troughs. The flow loss is bigger while the cooling effectiveness is enhanced due to the change of amplitude of the liner.

Soft Robotic Gripper With Compliant Cell Stacks for Industrial Part Handling

Robot object grasping and handling requires accurate grasp pose estimation and gripper/end-effector design, tailored to individual objects. When object shape is unknown, cannot be estimated, or is highly complex, parallel grippers can provide insufficient grip. Compliant grippers can circumvent these issues through the use of soft or flexible materials that adapt to the shape of the object. This letter proposes a 3D printable soft gripper design for handling complex shapes. The compliant properties of the gripper enable contour conformation, yet offer tunable mechanical properties (i.e., directional stiffness). Objects that have complex shape, such as non-constant curvature, convex and/or concave shape can be grasped blind (i.e., without grasp pose estimation). The motivation behind the gripper design is handling of industrial parts, such as jet and Diesel engine components. (Dis)assembly, cleaning and inspection of such engines is a complex, manual task that can benefit from (semi-)automated robotic handling. The complex shape of each component, however, limits where and how it can be grasped. The proposed soft gripper design is tunable by compliant cell stacks that deform to the shape of the handled object. Individual compliant cells and cell stacks are characterized and a detailed experimental analysis of more than 600 grasps with seven different industrial parts evaluates the approach.

Recent Developments of Materials used in Air breathing and Advanced Air breathing Engines

Jet engines require special materials that can withstand the demanding environments imposed on the various components and sections, so selection of materials is primary requirement during design of jet engine components. This paper is the study of various materials and their applicability for different components of jet engine for the purpose of enhancing the performance, reliability and durability. Review of materials for different types of jet engines such as turbojet engine, turboprop engine, turbofan engine, turboshaft engine, ramjet and scramjet engine is presented. This paper overviews the properties and materials used for different types of jet engines and can be used for further researchers in the field of jet engine materials.

Rare earth metals utilization opportunities in the development of Indonesia defense industry technology

Industrial technology developments that entered the era of 4.0, other than to utilize the development of technology which based on the internet of things, big data, artificial intelligence, cloud, etc., also need to be supported by advanced material technology capabilities, namely rare earth metals. In the defense industry, rare earth metals used in defense and security equipment such as military vehicle coating materials that are able to dodge or absorb waves of enemy radar detection, jet engine components of aircraft fighter, missile weapons systems, electronic components, subsea detectors, satellite devices and material for radar, etc. This research was conducted through literature review and using the SWOT analysis method on the opportunities for the use of rare-earth metals in Indonesia defense industry products. The data used are secondary data, which includes data on the distribution of rare earth metals in Indonesia and the specifications of the use of rare-earth metals in the defense industry. Based on the defense requirements for defense products and the percentage of rare earth metals content in the territory of Indonesia, one of the opportunities for the use of rare-earth metals for defense industry products is in the application of anti-radar layers.

Introducing design for selective laser melting in aerospace industry☆

Abstract The selective laser melting (SLM) process has created new possibilities for the manufacture of new lightweight jet engine components with lattice structures replacing solid sections. Hopes are to reduce the density of the component and thereby saving weight. To introduce the new manufacturing process, the components need to be redesigned and verified to comply with an array of requirements concerning, for example, strength, aerodynamics, and manufacturing. To find out how a capability of designing and evaluating components for the SLM process can be built into an organization, an interview investigation has been conducted at an aerospace company finding the state of practice in technology and product development. The impact of introducing SLM is thereafter estimated. The result is that introducing a novel manufacturing process will primarily influence the methods used to predict product lifecycle performance. An important finding is that it is currently difficult to include a topology optimization step in the multiobjective design evaluation environment used at the company due to which the complexity would increase significantly.

Designing as playing games of make-believe

Designing complex products involves working with uncertainties as the product, the requirements and the environment in which it is used co-evolve, and designers and external stakeholders make decisions that affect the evolving design. Rather than being held back by uncertainty, designers work, cooperate and communicate with each other notwithstanding these uncertainties by making assumptions to carry out their own tasks. To explain this, the paper proposes an adaptation of Kendall Walton’s make-believe theory to conceptualise designing as playing games of make-believe by inferring what is required and imagining what is possible given the current set of assumptions and decisions, while knowing these are subject to change. What one is allowed and encouraged to imagine, conclude or propose is governed by socially agreed rules and constraints. The paper uses jet engine component design as an example to illustrate how different design teams make assumptions at the beginning of design activities and negotiate what can and cannot be done with the design. This often involves iteration – repeating activities under revised sets of assumptions. As assumptions are collectively revised, they become part of a new game of make-believe in the sense that there is social agreement that the decisions constitute part of the constraints that govern what can legitimately be inferred about the design or added to it.

The Quality Assurance of Cast and Wrought Aero Jet Engine Components Made from Ni-base Superalloys with Using of Quantitative Metallography Methods and Alloys Lifetime Prediction

Abstract The Ni-base superalloys are used in the aircraft industry for the production of aero engine most stressed parts, turbine blades or turbine discs. Quality of aero jet engine components has a significant influence on the overall lifetime of a jet engine as itself as well as the whole airplane. From this reason a dendrite arm spacing, grain size, morphology, number and value of γ′-phase are very important structural characteristics for blade or discs lifetime prediction. The methods of quantitative metallography are very often used for evaluation of structural characteristics mentioned above. The high-temperature effect on structural characteristics and application of quantitative methods evaluation are presented in this paper. The two different groups of Ni-base alloys have been used as experimental material: cast alloys ZhS6K and IN713LC, which are used for small turbine blades production and wrought alloys EI 698VD and EI 929, which are used for turbine disc production. Selected alloys have been evaluated in the starting stage and after applied heat-treatment at 850°C for 24 hrs. This applied heat-treatment causes structural changes in all alloys groups. In cast alloy dendritic structure is degraded and gamma prime average size has grown what has a negative influence on turbine blade creep rupture life. Wrought alloys show partially grain boundary melting and grain size changed due to recrystallization what causes mechanical properties decreasing – ultimate tensile strength mainly.

The Influence of Shell Mold Composition on the As-cast Macro- and Micro-structure of Thin-Walled IN713C Superalloy Castings

In the investment casting process, the building of ceramic layers around the wax pattern is the main time-consuming stage. Increasing their number ensures sufficient mechanical properties, but also lengthens the whole process, including drying time and preheating of the mold. Four molds for casting Ni-based superalloy IN713C were strengthened by glass fibers, included in the slurry, and metal powder, of Al, Cu, Fe or Ni, in the coverage. Castings were subjected to microstructural investigations in order to find out if the new design can be promising for the manufacture of jet engine components. Bend tests revealed that the green strengths of all new molds were higher, at least 3.65 MPa, than that of the unmodified molds, 3.0 MPa. Optical microscopy revealed that the composition of a mold had a strong influence on stereological parameters of equiaxed IN713C grains. Microstructural observation and hardness measurements of castings revealed differences in the volume fraction of strengthening phases, porosity and hardness. The microstructure due to the complex chemical composition of IN713C consisted of several phases including ternary eutectics as a consequence of L → γ + Ni7Zr2 + (Nb, Zr)C.

Analysis of Maintenance Systems in Jet Dyeing Machine Components Using the Age Replacement Method

Purpose: The purpose of this study was to determine the maintenance intervals of critical components of jet dyeing machines in an effort to minimize downtime and calculate maintenance costs for engine damage to the jet dyeing. Design/ methodology/ approach: In this study an optimization method was developed to determine the replacement interval of a critical component, namely the Age Replacement Method. Findings: Based on the results of the calculation interval obtained preventive care critical components of jet engines during dyeing 1549 hours. It means that the component must be replaced before operation for 1549 hours or there is 6 times the turnover of prevention under taken in the interval of one year and the resulting decrease in the total cost of 82%. Research limitations/ implications: A review conducted in this paper against one component only, and then it can be developed for this type of component production machines. Practical implications: If the company is implementing a policy of replacement of critical components of the engine on the jet dyeing machine with a method of age replacement, then it will occur treatment cost savings amounting to Rp. 6,752,886 lower when compared with the initial conditions the company previously Rp 37,441,132. Originality/ value: This study combines the Pareto Diagram method and the Age Replacement Method to obtain optimum maintenance scheduling.

Mixed Mode Crack Growth in Functionally Graded Material Under Three-Point Bending

Functionally graded materials, FGM, permit tailoring the material volume fractions to extract maximum benefit from their in-homogeneity. Such materials offer great potential for components, which operate under severe thermal or mechanical loadings, such as spacecraft heat shields, plasma facings for fusion reactors, crucial jet fighter structures and engine components. In the present work, polyester matrix reinforced by varying glass fiber distribution was used to obtain FGM polymeric composites. The hand lay-up technique was adopted to manufacture the FGM. The mixed mode crack path of glass fiber/polyester FGM under three point bend, 3PB, was observed. The mechanical properties, such as tensile and flexural strength were determined experimentally and numerically. Pre-cracks with different lengths and locations with seven different inclination angles were considered to study the mixed mode crack growth of FGM. For the same crack length, the present results showed that the maximum applied load increased with increasing the crack inclination angle, i.e. the mode of mixity increased to reach pure mode II. Generally, the crack path initiated from the original inclination angle and grew along a curvilinear trajectory to extend toward the upper loading point.

Design margins: a hidden issue in industry

In complex products the values of parameters are rarely exactly the required values, rather they often have a margin that might be designed in deliberately or be the incidental results of other design decisions. These margins play a critical role in design processes in managing engineering change and iteration. While engineers often talk about margins informally, designers and researchers also use other terms for specific margin concepts. This paper reviews the existing literature on related concepts and defines margins formally. It discusses the role margins play in handling uncertainty by distinguishing between buffer and excess. Buffer deals with uncertainty and excess with the remaining overcapacity of the design. Buffer can transition into excess of the design solution if the uncertainty can be reduced. The concepts are applied to the temperature margins of several candidate materials for a non-rotary jet engine component. This shows that a clear understanding of margins can help a company to select design alternatives.