Annular Parts Research Articles

Co-rotating electrochemical machining of convex structures on the inner surface of annular parts using a flexible cathode tool

Thin-walled annular parts are widely used in the aerospace industry. There are some irregular island structures with non-periodic distribution on the inner surfaces of annular parts, which poses a significant challenge to manufacture such annular parts using conventional mechanical methods. Electrochemical machining (ECM) has exhibited good prospects for manufacturing thin-walled annular parts, with the advantages of no tool wear, no processing deformation and a high material removal rate. However, there is little research related to fabricate convex structures on the inner surfaces of annular parts, although ECM is vital to the machining of thin-walled annular parts. In this study, a flexible cathode tool was used to machine irregular convex structures on the inner surfaces of annular parts via co-rotating ECM. The complex motion of the cathode tool and conductive slider was simulated using matrix equations, and the digital simulation of the material removal process was realized based on matrix equations and Faraday's law. Based on the mathematical model, a design method for a flexible cathode tool was developed, and three main parameters were determined: the position of the window, radius of the cathode, and width of the window. Comparative experiments were performed using the flexible and conventional cathode tools. The results showed that the selective removal of convex structures was achieved by using the flexible cathode tool. The insulated sheet needed to be attached to the position where the convex structure was retained. An aero-engine casing with many irregular island structures on the inner surface was successfully machined. The height of the fabricated island structure is 6 mm. The sidewall thickness of the aero-engine casing is 1.2 mm. Therefore, co-rotating ECM with a flexible cathode tool offers excellent machining ability for irregular island structures on the inner surfaces of annular parts.

Scanning Strategy of Multi-Layer and Multi-Track Laser Cladding for Radial Grooves of Annular Thin-walled Parts

Scanning Strategy of Multi-Layer and Multi-Track Laser Cladding for Radial Grooves of Annular Thin-walled Parts

Evolution of the Interelectrode Gap during Co-Rotating Electrochemical Machining

A new co-rotating electrochemical machining method is presented to machine the complex structure inside annular parts such as flame tubes and aero-engine casings. Due to the unique shape and motion of electrodes, it is difficult to accurately compute the electric field intensity in the machining area. In this paper, the complex electric field model is simplified by conformal transformation, and the analytical solution of electric field intensity is exactly calculated. A material removal model is built on the basis of the electric field model, and the dynamic simulation of the material removal process is realized. The effects of the cathode radius, applied voltage, feed rate and initial interelectrode gap on the interelectrode gap (IEG) and material removal rate (MRR) are analyzed. The simulation results indicate that the MRR is always slightly less than the feed rate in a quasi-equilibrium state, resulting in a slow reduction in IEG. In addition, the final machining state is not affected by the initial IEG, and the MRR in a quasi-equilibrium state is determined by the feed rate. Several comparative experiments were carried out using the optimized processing parameters, in which the MRR and IEG were measured. The convex structures were successfully machined inside the annular workpiece with optimum machining parameters. The experimental results are in good agreement with the theoretical results, indicating that the established model can effectively predict the evolution process of MRR and IEG.

Physical prior and Tikhonov regularization based residual stress inference method for annular parts using deformation force

Physical prior and Tikhonov regularization based residual stress inference method for annular parts using deformation force

Deformation characteristic and microstructure evolution of GH4169 alloy induced by axial upsetting and axial rotary forging

Axial rotary forging (ARF) is a representative of processes with local deformation of the formed blank which is suitable for axisymmetric parts, such as disk-shaped parts and annular parts. Axial upsetting (AU) has been considered as the most widely used technology for preparing blank of aerospace disks. In the current work, deformation Characteristic and microstructure evolution of GH4169 alloy Induced by Axial upsetting and Axial rotary forging was investigated by simulation and experiment. Higher strain was observed at ARF deformation with same high reduction. And the higher stain conducted at comparative lower temperature induced the static recrystallization during followed anneal process which is special for hot processing of GH4169 alloy. The mechanism was also announced in this paper.

A mechanism informed neural network for predicting machining deformation of annular parts

Controlling machining deformation of annular parts is crucial for ensuring the performance of high value products and equipment. For example, during manufacturing of critical parts in aircrafts and spacecrafts, accurate prediction of machining deformation is the basis for guiding the formulation of deformation control strategies. However, due to the complexity of the machining deformation of annular parts, existing methods still have limitations in accurate prediction. To this end, this paper proposes a mechanism informed neural network (MINN) to predict machining deformation of annular parts. MINN is realized by establishing the dual sub-networks structure and using enhanced loss functions with the consideration of the deformation mechanism model characteristics of annular parts. The deformation was decomposed into the axisymmetric portion and the non-axisymmetric portion according to the deformation superposition principle, and modeled separately based on the thin-shell theory and Fourier series. Experiment results showed that the proposed method could predict the machining deformation of annular parts more accurately and stably with a small amount of training data, compared with previous methods.

Assembly method for two symmetrical bolt-bearing joints based on the tightening model and angle-eccentricity relationship

This paper focused on the assembly of two symmetrically distributed bolt-bearing joints, both the single bolt tightening control and two bolts adjusting were studied. An improved assembly method for two annular parts connected by these two bolt-bearing joints was proposed to improve the tightening quality of these joints and the eccentricity between these two annular parts. First, the tightening process of single bolt-bearing joint was analyzed, and the mathematical model of the tightening process was established. Then, aiming to improve the tightening quality, an improved tightening control method for single bolt-bearing joint was proposed based on the mathematical model. Finally, the angle-eccentricity relationship was studied, and the eccentricity adjustment strategy based on the inverse sequence method was presented for adjusting the eccentricity between two connected parts. Considering that the measurement of the bearing preload is not convenient, the eccentricity was measured for indirectly reflecting the preload. The tightening experiments verified that the scatter of preload was obviously reduced under the improved tightening control method. The results of eccentricity adjustment experiments indicate that the eccentricity reduce gradually during the loosening and tightening process, and the eccentricity is less than 3.4 μm after adjustment process, which enough to meet the assembly requirements of the target groupware.

Setup of a Mobile Robot Machine Tool for Large Annular Parts

Setup of a Mobile Robot Machine Tool for Large Annular Parts

Sub-pixel dimensional and vision measurement method of eccentricity for annular parts.

Eccentricity measurement of annular parts with millimeter scale and micrometer precision requirements is widely used in mechanical engineering applications. To realize accurate eccentricity measurement for large-scaled annular parts, a vision-based and sub-pixel dimensional measurement method is proposed. First, to facilitate the eccentricity measurement, an improved auto focus algorithm is introduced to provide better focused images of the measured parts. Then the traditional Canny operator is modified in gradient direction calculation and a double threshold process to locate the pixel edge more accurately. Next, a model-based sub-pixel edge detection method is studied to extract the sub-pixel edge coordinates. Finally, the eccentricity is calculated according to these sub-pixel edge coordinates. To guarantee measurement accuracy, the pixel equivalent and manual installation error of three degree of freedom (DOF) stages are calibrated, and the verification experiments indicate that the measurement error of the proposed method is better than 1.0 µm.

Numerical simulation based radial laser cladding process optimisation for annular thin-walled parts

Numerical simulation based radial laser cladding process optimisation for annular thin-walled parts

Transforaminal Endoscopic Lumbar Discectomy: Basic Concepts and Technical Keys to Clinical Success.

Open microdiscectomy is the gold standard surgical technique for radiculopathy with lumbar disc herniation (LDH). Transforaminal endoscopic lumbar discectomy (TELD) has been developed as an effective and minimally invasive alternative to open surgery. As a result of these remarkable technical evolutions, the clinical outcomes of TELD have become comparable to those of conventional open surgery. However, considerable learning curves and endoscopy-related adverse events may emerge as critical problems. The objective of this article was to inform on the basic principles, surgical techniques, and keys to clinical success in preventing complications. A narrative review of the literature focused on the surgical indications, technical tips, complications, and learning curve of the full-endoscopic procedure was performed. First, the transforaminal endoscopic system should access as close as possible to the target point, avoiding exiting nerve root irritation. Second, selective removal of the herniated disc fragments after sufficiently releasing the annular anchorage parts is essential to avoid incomplete decompression or prevent an early recurrence. Third, the endpoint of the procedure can be determined at the point of solid pulsation and free mobilization of the nerve root. Finally, surgeons should always ensure that the anatomical layers discriminate the neural tissue and disc material during the procedure.Some authors have demonstrated the effectiveness of TELD through randomized controlled trials, meta-analyses, and systemic reviews. According to these studies, the clinical outcomes of TELD are not inferior to those of open discectomy, with an earlier recovery period and fewer complications. The full-endoscopic transforaminal discectomy technique for soft LDH is an effective alternative with the benefits of minimally invasive surgery in appropriately selected patients. Given recent technical developments, the surgical indications for TELD will be broader and the clinical outcomes will be more reliable.

A novel traveling wave piezoelectric actuated wheeled robot: design, theoretical analysis, and experimental investigation

Traditional traveling wave robots have strict requirements on the operating interface due to the fact that they usually only work on smooth and flat surfaces, holding the disadvantages of poor load capacity and complex driving mode, and limiting their application range. In order to overcome the above problems, a novel traveling wave piezoelectric actuated wheeled robot is proposed in this study. The robot is composed of a bonded-type piezoelectric actuator and wheel mechanisms. Rotating traveling wave can be produced in the annular parts of the piezoelectric actuator to drive the wheel mechanisms. In order to study the dynamic characteristics of the piezoelectric actuator, an electromechanical coupling model is developed by using the transfer matrix method. Then the prototype of the piezoelectric actuator is fabricated and assembled, and its vibration characteristics are measured to confirm the feasibility of the developed transfer matrix model. Finally, performance evaluation investigations of the proposed traveling wave piezoelectric actuated wheeled robot are conducted. Under the excitation voltages of 350 V pp and the phase difference of 90°, the robot prototype achieved a step climbing angle of 75°, a maximum no-load velocity of 136.8 mm s−1, and a maximum payload of 320 g. The proposed traveling wave piezoelectric actuated wheeled robot presents expected terrain adaptability and obstacle climbing capability.

Development of Resource-Saving Technological Processes for Manufacturing Rings by the Compression Method

Based on the developed methodology for designing technological processes for producing annular parts by compression, we developed technological processes for manufacturing parts "Flange" and "Thrust ring", which make it possible to increase the material utilization factor (MUF) and reduce material consumption. A comparative analysis of MUF in the manufacture of annular parts by cutting and punching rings with cutting and punching of an oval workpiece and subsequent compression.

РЕСУРСОСБЕРЕГАЮЩАЯ ТЕХНОЛОГИЯ ИЗГОТОВЛЕНИЯ КОЛЬЦЕВЫХ ДЕТАЛЕЙ МЕТОДОМ СЖАТИЯ

On the basis of the developed methodology for designing technological processes for producing annular parts by compression, technological processes for manufacturing parts "Flange" and "Thrust ring" have been developed, which make it possible to increase the material utilization factor and reduce material consumption. A comparative analysis of material utilization factor in the manufacture of ring parts by punching and punching rings with punching and punching of an oval blank and subsequent compression.

Research of sparing technologies of tunneling

In the work, various tunneling technologies were considered. Separately analyzed force factors and torque. The axial and radial forces acting on the breed arising in the presence of a conical part of the tool are estimated. Three ways to balance the torque are considered. A moments alignment device is described for a method by dividing a penetration zone into annular and circular parts. As a criterion for the choice of technology, it is proposed to use the indicator of the stress-strain state that occurs at the time of penetration, calculated in accordance with the theory of the highest tangential stresses. The study of four different tunneling technologies by the selected criterion showed that they can be ranked by the created stress-strain state. At the same time, the generated stresses are affected not only by the driving conditions in the form of axial force and torque, but also by the presence and size of the conical part of the tool, as well as torque equalization devices. The smallest stresses in the rock are created with direct selection technology, since there is no torque, and due to local selection with a small tool, the axial pressure decreases. In second place in preference is the technology with equalization of moments, however, it is based on a rather complex technical device. The largest load on the breed is provided by the shield technology of sinking due to the simultaneous presence of both axial force and torque.

The use of profilometry techniques and eigenstrain theory for the analysis of creep behavior in nickel superalloy welds

This paper presents a summary of recently developed experimental and computational tools to reconstruct residual stress fields and analyze creep in nickel superalloy welds used in aerospace engineering components. This approach combines experimental data with eigenstrain theory to reconstruct stress fields at the macroscopic scale and provided reliable means for numerical prediction of creep behavior of welded components under complex loading conditions. Experimental data in the form of profilometry scans was interpreted using a range of iterative eigenstrain methods that included the adaptation of the contour method and artificial intelligence models for eigenstrain-creep analysis. The integration of principles of artificial intelligence with eigenstrain models allowed highly accurate results to be obtained which were validated by comparison with experimental data obtained using independent techniques such as neutron diffraction. The use of artificial intelligence models is discussed for residual stress reconstruction and creep behavior prediction in annular aeroengine parts manufactured using inertia friction welding. To extend the range of experimental data taken into consideration, the height Digital Image Correlation (hDIC) technique was introduced that utilizes information regarding triaxial displacements obtained from profilometry, allowing deeper and more reliable analysis to be conducted. The hDIC technique was validated using operando tensile testing data.

Three-Dimensional Free Vibration Analysis of Gears with Variable Thickness Using the Chebyshev–Ritz Method

To reflect vibration more comprehensively and to satisfy the machining demand for high-order frequencies, we presented a three-dimensional free vibration analysis of gears with variable thickness using the Chebyshev–Ritz method based on three-dimensional elasticity theory. We derived the eigenvalue equations. We divided the gear model into three annular parts along the locations of the step variations, and the admissible function was a Ritz series that consisted of a Chebyshev polynomial multiplying boundary function. The convergence study demonstrated the high accuracy of the present method. We used a hammering method for a modal experiment to test two annular plates and one gear’s eigenfrequencies in a completely free condition. We also applied the finite element method to solve the eigenfrequencies. Through a comparative analysis of the frequencies obtained by these three methods, we found that the results achieved by the Chebyshev–Ritz method were close to those obtained from the experiment and finite element method. The relative errors of four sets of data were greater than 4%, and the errors of the other 48 sets were less than 4%. Thus, it was feasible to use the Chebyshev–Ritz method to solve the eigenfrequencies of gears with variable thickness.

A novel sandwich-type traveling wave piezoelectric tracked mobile system

In this paper, a novel sandwich-type traveling wave piezoelectric tracked mobile system was proposed, designed, fabricated and experimentally investigated. The proposed system exhibits the advantages of simple structure, high mechanical integration, lack of electromagnetic interference, and lack of lubrication requirement, and hence shows potential application to robotic rovers for planetary exploration. The tracked mobile system is comprised of a sandwich actuating mechanism and a metal track. The actuating mechanism includes a sandwich piezoelectric transducer and two annular parts symmetrically placed at either end of the transducer, while the metal track is tensioned along the outer surfaces of the annular parts. Traveling waves with the same rotational direction are generated in the two annular parts, producing the microscopic elliptical motions of the surface particles on the annular parts. In this situation, if the pre-load is applied properly, the metal track can be driven by friction force to achieve bidirectional movement. At first, the finite element method was adopted to conduct the modal analysis and harmonic response analysis of the actuating mechanism, and the vibration characteristics were measured to confirm the operating principle. Then the optimal driving frequency of the system prototype, namely 35.1kHz, was measured by frequency sensitivity experiments. At last, the mechanical motion characteristics of the prototype were investigated experimentally. The results show that the average motion speeds of the prototype in dual directions were as 72mm/s and 61.5mm/s under the excitation voltage of 500VRMS, respectively. The optimal loading weights of the prototype in bi-directions were 0.32kg and 0.24kg with a maximum speed of 59.5mm/s and 61.67mm/s at the driving voltage of 300VRMS, respectively.

Block-by-block and layer-by-layer growth modes in coral skeletons

Understanding the dynamics of biomineral growth is a challenging goal of biomineralogy that can be achieved in part by deciphering biomineral structures and chemistries. The morphology, structure, and chemistry of six skeletons of Corallium and Paracorallium species ( C. rubrum , C. elatius , C. johnsoni , C. niobe , P. japonicum , and P. thrinax ) from the Mediterranean, the Atlantic, and the Pacific oceans have been studied by X-ray micro-computed tomography, polarized light microscope, scanning electron microscope, and electron microprobe. All species have two types of biomineral structures: an inner skeleton and sclerites that are small grains of Mg-calcite found in the living tissues surrounding the skeleton. All skeletons display a central core surrounded by an annular domain. In the species studied by electron microprobe ( C. rubrum , C. elatius , and P. japonicum ), the central core and the annular domains display different chemical compositions with the core richer in magnesium and poorer in sulfur than the annular domain. In terms of structure, special emphasis has been put on central cores for which little data are available. The central cores are made of sclerites and sclerite aggregates within a cement consisting of fine layers of Mg-calcite. On the other hand, the annular parts are made of fine concentric layers of calcite crystallites with only rare sclerites. These contrasting features imply two different growth modes: (1) a “block and cement” mode taking place at the apex of a branch and associated with a fast axial growth rate (~2 mm/yr); and (2) a layer-by-layer mode occurring below the apex and associated with a slow radial growth (~0.2 mm/yr). The change from a growth mode to another is anatomically controlled by the presence of a continuous network of gastrodermal canals around the sub-apical skeleton, preventing to a large extent the aggregation of sclerites. It is generally accepted that the Coralliidae family exhibits different types of skeletogeneses. In contrast with this idea, we observe that all studied Corallium species display remarkable similarities in terms of skeletogenesis and a unifying growth model for the Corallium genus is proposed. Similarities and differences with previous models are discussed. The present study shows that the morphological criterion initially used to establish the genus Paracorallium in the Coralliidae family is inadequate.

A piezoelectric tracked vehicle with potential application to planetary exploration

A piezoelectric driving method for rover vehicles is proposed in this paper. Employing this method, a tracked vehicle driven by friction forces from a frame mounted with piezoelectric elements was developed. The vehicle is designed with no driver sprocket, no idler-wheel and no supporting bogie wheels, and the vehicle thus requires no lubrication and has potential application in planetary exploration. The frame consists of a pair of piezoelectric transducers. Each transducer comprises four annular parts jointed by beams adhered with piezoelectric ceramics. The tracks are set to the outer surface of the annular parts by means of track tension. Traveling rotating waves are generated by piezoelectric transducers in the annular parts, which generate microscopic elliptical motions at the interface of the tracks. The microscopic elliptical motions from the piezoelectric transducers drive the track vehicle to move. Finite elements analysis was carried out to verify the operation principle using commercial software ANSYS. Piezoelectric transducers were fabricated, assembled and tested to validate the concepts of the proposed rover vehicle and confirm the simulation results. A prototype vehicle with mass of 0.57 kg moves at a speed of 4.3 mm/s at a driving voltage of 250 V and operating frequency of 65.53 kHz.