Flange Structure Research Articles

Comparison of the effects on heat transfer through oil oscillation in a steel piston cooling gallery: Friction welding versus laser welding

Piston cooling gallery plays a critical role in managing the temperature of the piston and its performance. This paper aims to study the effect of oscillatory heat transfer within the cooling galleries, focusing on two distinct types: flanged (friction-welded) and smooth structures (laser-welded). To do so, the Eulerian multiphase flow model and the k-ω SST turbulence model were used to simulate the oil and air flow through the cooling gallery. Key parameters such as the oil filling rate, wall heat transfer coefficient, oil outlet flow rate, heat removal rate by the oil, and overall wall heat transfer rate were assessed for both gallery designs at an engine speed of 1800 r/min. The results indicate significant disparities between the two cooling gallery structures: the smooth structure exhibits an oil filling rate that is 5.41% higher and an oil outlet flow rate that is 33.48% greater compared to the flanged structure. The flange structure impedes internal oil movement, which leads to boundary layer separation, secondary wall contact, and the emergence of a double vortex phenomena. Collectively, these factors influence the oil fill ratio. This, in turn, affects the distribution of oil within the gallery and, subsequently, the efficiency of heat transfer. Comparative analyses of heat transfer within both galleries, under the same studied conditions, revealed that the smooth structure outperforms the flanged one. However, the presence of a flange significantly alters the heat contribution from different walls, thereby highlighting the substantial impact of flanges on the overall efficiency of heat transfer.

Use of an Osseointegrated Intraosseous Transcutaneous Amputation Prosthesis for Amputated Fingers Is Followed by Frequent Infection and Implant Removal

ABSTRACT Introduction We report on the outcomes of using a custom-built osseointegrated (OI) intraosseous transcutaneous amputation prosthesis (ITAP) as a bone anchor for prosthetic reconstruction of a series of amputated fingers. The aim of ITAP was to reduce the risk of failure due to infection by creating a biological seal at the skin-implant interface. Methods and Results A total of 14 patients who suffered from amputations of their digits at a variety of different levels were recruited. Eleven patients (20 implants) underwent treatment with an implant based on the ITAP principle. With the exception of one patient (1 implant), all implants were removed by 9 years after insertion. Patients requested removal because of recurrent infections, exposure of the flange structure (unique to ITAP), loosening of the implant, and inability to secure a prosthesis to the implant. Conclusions The ITAP principle does not work when used as part of the design of an OI bone anchor for prosthetic reconstruction after finger amputation. Clinical Relevance Statement This study suggests that there are major problems with the principles underlying the design of the ITAP implant when used in humans. Future studies of OI implants using the principles of ITAP may be at risk of similar problems.

A thrust vector control test system of large range solid rocket engine utilizing a four-point support piezoelectric dynamometer and a deflected flange structure

The accurate measurement of thrust vector is very important to improve the life and safety of aircraft engine. In order to meet the requirements of thrust vector test of a solid rocket engine and overcome the contradiction between large thrust (>50 kN) and high-frequency response (≫30 Hz)/high precision measurement (<3%), a thrust vector control test system utilizing a four-point support piezoelectric dynamometer (FSPD) and a deflected flange structure was proposed. The test system mainly consists of a four-point support piezoelectric dynamometer and some vector force simulation loading devices. The theoretical mechanical model and the thrust vector control test system was set up to study the performance of solid rocket engine. Firstly, the piezoelectric elements and four-point support piezoelectric dynamometer were calibrated by the three-direction force calibration loading device. Secondly, the rationality and feasibility of the thrust vector control test system were proved by the simulated loading experiment. The research results show that the static and dynamic performance of the test system meet the test requirements, and it has good linearity and repeatability, errors are less than 1.00 %, and interphase interference is less than 2.00 %. The measuring system proposed in this paper provides a new idea for the accurate measurement of vector force with large load and high-frequency response.

Life prediction and optimal design of flange structure of tire unloader

Life prediction and optimal design of flange structure of tire unloader

Bifurcation Analysis of a Rotor-Casing Coupling System with Bolted Flange Connection under the Effect of Rotor-Casing Rubbing Fault

This study mainly investigated the nonlinear vibration performance of a rotor-casing coupling system containing a bolted flange connection. The dynamic equations of the coupling system were developed while considering the radial stiffness of the bolted flange structure, which contained a spigot, squirrel cage with ball bearing, and rotor-casing coupling vibration. To study the influence of the disk casing fixed-point rubbing fault on the coupling system’s nonlinear dynamic performance, an analytical model of the nonlinear impact forces was established, which considered the contact and vibration responses of the rotor and casing. The frictional force was obtained based on the Coulomb friction law. The iterative analysis of motion equations was performed utilizing the Newmark method. Then, the nonlinear dynamic behaviors of the coupled systems were examined using data, including a bifurcation diagram, spectrum plot, greatest Lyapunov exponents, etc. The effects of rubbing fault on the dynamic properties of system were investigated in detail, indicating that there were various motion states, which were described as periodic, multi-periodic, and quasi-periodic motions. Comparing the simulation results, it was found that rubbing fault seriously affected the motion stability of the rotor system. Finally, by gathering and examining the vibration data set from a test platform for rotor-casings with bolted joints, the correctness of the numerical simulation findings was confirmed. Additionally, the results of the experimental investigation agreed with that of the simulation. The dynamic distinguishing characteristics that were noticed can be used as an indicator for determining whether the fixed-point rubbing fault between the rotor and casing has become worse.

Influence of topology optimization parameters on the mechanical response of an additively manufactured test structure

Topology Optimization (TO) determines a material distribution within a domain under given conditions and design constraints, and generally generates complex geometries as a result. Complementary to TO, Additive Manufacturing (AM) offers the ability to fabricate complex geometries which may be difficult to manufacture using traditional techniques such as milling. AM has been used in multiple industries including the medical devices area. Hence, TO may be used to create patient-matched devices where the mechanical response is catered to a particular patient. However, during a medical device regulatory 510(k) pathway, demonstrating that worst-cases are known and tested is critical to the review process. Using TO and AM to predict worst-case designs for subsequent performance testing may be challenging and does not appear to have been thoroughly explored. Investigating the effects of TO input parameters when AM is employed may be the first step in determining the feasibility of predicting these worst-cases.In this paper, the effect of selected TO parameters on the resulting mechanical response and geometries of an AM pipe flange structure are investigated. Four different input parameters were chosen in the TO formulation: (1) penalty factor, (2) volume fraction, (3) element size, and (4) density threshold. Topology optimized designs were fabricated using PA2200 polyamide and the mechanical responses (reaction force, stress, and strain) were observed through experiments (universal testing machine and 3D Digital Image Correlation) and in silico environments (finite element analysis). In addition, 3D scanning and mass measurement were performed to inspect the geometric fidelity of the AM structures. A sensitivity analysis is performed to examine the effect of each TO parameters. The sensitivity analysis revealed mechanical responses can have non-monotonic and non-linear relationships between each tested parameter.

Undamped Non-linear Vibration Mechanism of Bolted Flange Joint under Transverse Load

Bolted flange joints are commonly utilized in engineering constructions; nevertheless, their dynamic behavior is complicated when nonlinearity is present. The bolted flange joint structure in this research is considered as a spring-mass system, and the equivalent axial two bi-linear springs-bending beam model, as well as the system’s vibration control equation, is created to examine the joint structure’s vibration characteristics under transverse stress. The results indicate that when the spring stiffness is constant and the stiffness is a linear function of displacement, and the mass matrix of the vibration control equation is coupled, the system produces only transverse vibration upon transverse impact; when the spring axial stiffness is a linear function of displacement and the mass matrix of the vibration control equation is not coupled, the spring stiffness is bilinear and the stiffness is a quadratic function of displacement, the system will vibrate transversely and longitudinally under the transverse impact. Regardless of how the spring stiffness is simplified, the system’s transverse or transverse and axial movement is a stable periodic vibration with a vibration response proportional to the system’s mass and the radius L of the connected cylindrical shell. The theoretical method verifies the nonlinear vibration characteristics of the bolted flange structure under transverse load, which is of great significance for proposing new methods and models.

Influence of Flange Structure Parameters on Contact Pressure of the New‐Type Wedge Ring Gasket

AbstractAs a sealing element, the new‐type wedge ring gasket required the usage of flanges to achieve sealing. On the basis of previous research, the influence of flange structural parameters on the contact pressure of the sealing surface of the new wedge ring gasket was studied by finite element analysis. The effective thickness of the flange had the greatest influence on the contact pressure of the main and slave sealing surfaces, followed by the thickness of the big end of the cone neck, the outer diameter of the flange, and the height of the flange neck. The flange structure parameters were optimized by an orthogonal experiment, and the maximum contact pressure of the sealing surface of the gasket was obtained under optimized conditions. The results provided a basis for the selection of structural parameters of the flange used with the new‐type wedge ring gasket.

Design of cryogenic test platform for the seal structure in superfluid helium temperature

A cryogenic test platform was conceived and designed with a variable temperature from 1.8K to 300K to accomplish the research of cryogenic seal performance, and the main research object of this platform is to test the seal capacity of the flange structure in superfluid helium condition. This platform mainly includes a cryostat, a set of vacuum pumps, a sealed test chamber, a cryogenic physical property test chamber, a leak detection system, a superfluid helium acquisition system, and temperature control systems. The cold source is supplied by 1.5K superfluid helium, which will be obtained by combining throttling with decompression. Mechanical structure designs and detailed parameters of the entire platform will be presented in this paper.

Synchronous detection of bolts looseness position and degree based on fusing electro-mechanical impedance

Looseness is the most common form of failure in bolt connections, which can cause safety accidents by reducing the rigidity of the structural connection, and the detection of bolt looseness is vital to maintain the health of the structure. However, due to the limitations of existing methods, it is difficult to detect the position of loose bolt and degree of looseness synchronously. In this study, an Electro-mechanical impedance (EMI) detection method based on fusing multi-frequency ranges was proposed. Firstly, the feasibility of bolt looseness detection based on EMI technology was analyzed through theoretical deduction; secondly, the qualitative relationship between excitation frequency and detection range was explored through finite element simulation, which provides a basis for the proposed fusing multi-frequency ranges method, and the conclusion was verified in four-bolted flange structure; finally, a detection method for bolt looseness was proposed, which uses the impedance shift as the damage index, and detect the position of loose bolt and degree of looseness synchronously by fusing EMI in multiple frequency ranges. The verification results show that the proposed method can identify the loosening status of bolts in the flange structure with high accuracy.

Pose Estimation of GIS Pipeline Based on Spatial Transformation Network

The manual flange structure alignment between GIS pipelines in the power system is inefficient and difficult to accurately align. To solve this problem, combined with the research results in the field of deep learning named spatial transformation network, a new pose estimation method based on single camera is proposed. In view of the high similarity between the moving flange and the static flange at the pixel level, the spatial transformation network is used to find the pixel mapping relationship of the two flange images. Thereby establishing the mapping relationship between the pixel coordinates of the two flange images and then using multiple points. In the perspective method, the pixel coordinates are mapped to the world coordinates to obtain the estimation of the position of the key point in the flange, and then the direction vector of the flange is calculated according to the position of the key point. Since there is a pixel coordinate transformation relationship between the static flange and the movable flange. Only the position of the key point in the static flange can be inversely solved by measuring the position of the key point in the static flange. Experiments show that, compared to the traditional method of measuring flange pose based on instrument measurement and linear regression, the method proposed in this paper can accurately measure the pose of the flange structure. And it can rely as little as possible on the measurement of the key points of the moving flange by the instrument.

Model order reduction and dynamic characteristic analysis of the bolted flange structure with free-free boundaries

The problem of model order reduction and dynamic characteristic analysis of the bolted flange structure with free-free boundary conditions is studied by proposing a novel simplified modeling method. The proposed simplified modeling method is able to reduce the finite element model of the linear components through free-interface mode synthesis method and condense the number of degree-of-freedom of the joint interface through coordinate condensation, which can fix the model size not to increase with the number of bolts and greatly reduce the computational cost. Rigid-body mode elimination is also considered to further reduce the order of the integrated dynamic equation and avoid the problem of computational instability in the proposed simplified modeling method. An experimental bolted flange structure with free-free boundary conditions is built and the corresponding modal testing is carried out to verify the accuracy of the proposed simplified modeling method. Comparative results of modal testing and simulation indicate that gravity leads to unequal bending frequencies of the same order in X and Y directions, which also proves that the proposed simplified modeling method is able to analyze the dynamic characteristic of the bolted flange structure with free-free boundary conditions.

A novel Z-shaped elastic flange structure for increasing the amplitude output of a piezoelectric ultrasonic transducer

A novel Z-shaped elastic flange structure is presented in this paper, which is used to mount the piezoelectric ultrasonic transducer (PUTs) together with the housing and increase amplitude output of the transducer. Generally, the mounting fixture of the transducer refers to the traditional flat-faced flange structure, which has the advantages of low processing cost and easy installation. However, considering its structural characteristics, the flange structure also exerts a negative influence on the coupling between the transducer and housing and accordingly suppresses the conversion of ultrasonic vibration energy inside the transducer. The novel Z-shaped elastic flange is combined with a traditional flat-faced flange structure and an elastic cylindrical sleeve, and the amplitude output of the transducer is increased by reducing the longitudinal and radial coupling effect between the transducer and the flange. Ultrasonic transducers with different flange structures are designed and manufactured. Through the combination of Finite Element Method and experimental analysis, the decoupling and amplitude increase ability of the novel elastic flange are investigated in detail. The results show that without changing the stiffness of the transducer, the proposed Z-shaped elastic flange structure could significantly increase the amplitude output of the transducer, regardless of whether the transducer was working in a resonance state. Hence, the newly proposed structure serves as a meaningful attempt and can be used as a universal structure for PUTs in different fields.

Study on sealing performance of bolted flange structure after creep based on ABAQUS

In this paper, a finite element analysis model is established based on ABAQUS software and DN600 bolted flange connection structure is the research object. The elastic-plastic constitutive relation is adopted for the flange and bolt materials, and the user subroutine of Creep is written in Fortran language according to the creep constitutive equations. Each component can meet the requirements of strength and seal evaluation, and it is found that after creep, the seal stress of gasket decreases significantly, and the stress increases almost linearly from the inside to the outside of the gasket. After cooling and heating, the stress is redistributed. The residual pre-tightening force of bolt is increased, and the flange deflection angle is slowed down, which improves the sealing performance. The study of gasket sealing performance in this paper has a positive guiding significance for preventing leakage accidents.

Full-floor Grouting Reinforcement for Working Faces with Large Mining Heights and High Water Pressure: a Case Study in China

Grouting reinforcement was used to safely and efficiently exploit the thick coal seam in the Jiaozuo coalfield. First, the water inrush possibility of the 11,050 working face was evaluated, using both the floor failure depth and the water bursting coefficient (T) methods. The estimated depth of the floor failure zone (h) ranged from 22 to 38 m, which is larger than the average distance between the floor-confined aquifer (L8) and the no. 2 coal seam. Additionally, the water bursting coefficient of L8(0.268) was much higher than the ultimate Ts(0.100). Thus, the evaluation showed that the L8 confined limestone aquifer had a high water inrush possibility. Innovative grouting methods and supporting facilities, such as dispersed pulping, repeated pipe fixation, and three-stage flange structure, were proposed to address the threat. Finally, both drilling and geophysics (i.e. DC method) indicated that the grouting reinforcement had been effective.

Evaluation of Characterization Indexes and Minor Looseness Identification of Flange Bolt Under Noise Influence

Based on electromechanical impedance (EMI) technology, we studied the indication effect of each characterization index on flange bolt looseness under different noise levels. A new evaluation index T is constructed to solve the problem that the minor looseness and noise under the actual monitoring environment cannot be distinguished with existing indexes. The results show that among the five characterization indexes, the root mean square deviation (RMSD) and the correlation coefficient deviation (CCD) can reflect the minor looseness sensitively and are positively correlated with the degree of looseness. They also have good performance of looseness identification under the noise of 30 dBW. However, the indexes' indication range of the case under 1 dBW-6 dBW noise overlaps with the case under 36 N·m-39.5 N·m torque. So it is impossible to judge the structure state with mere characterization indexes. Evaluation index T can extract the correlation difference of the conductance spectrum under the noise conditions and looseness conditions with the benchmark respectively. And there are different indication ranges of T on the noise and minor looseness. By determining a threshold and comparing T with it, whether bolt looseness occurs in an unknown condition can be effectively judged. Finally, T is applied to other flange structure with 8 bolts to verify the effectiveness and general applicability of the method. The evaluation index plays an important role in avoiding misjudgment of flange bolt caused by noise influence on minor looseness and improving the ability of identification when the bolt is at the critical state.

Improvement of ionization chamber for tritium measurements in in-pile tritium extraction experiments

Ionization chamber with gold plated wire-wall based on flange structure has been developed for tritium measurements in in-pile tritium extraction experiments. Performance of the improved ionization chamber on airtight and memory effect was greatly enhanced. Gas leakage rate of the chamber was lower than 1.0*10−13 Pa. m3/s with the flange structure. Both tritiated water vapor and tritium in gaseous form have been used in experiments to examine the influence of memory effect caused by tritium absorption on chamber wall. Results indicate that with the design of gold plated wire wall, output signal of the ionization chamber can recover to background level within 1 min after 1 h exposure in tritiated water vapor at 3.0*108 Bq/m3 created by bubbling. While recovery time is less than 20 s after being exposed to tritium in gaseous form at 3.9*1010 Bq/m3 for 7 days.

Study the Influence of Geometric Parameters on Springback in T-Section Aluminum Alloy Window Trim Strip Sheets Forming

The T-section aluminum alloy window trim strip sheets are used to improve vehicle appearance. As the mobile scenery line, these window trim strips with claws need high forming accuracy to meet good assembly quality requirement. The top portion of the T-section sheet is stamped to form an edge flange structure. Springback control is essential in forming process. In this paper, the influence of the window trim strip geometric parameters on forming springback is studied. Some finite element models of the process were built with the Dynaform software. The simulation results were verified experimentally. The main conclusions include as belows: The different heights of the stiffeners part in T-section change the stiffness of the part. Although the stiffeners part does not participate in the forming, it also has springback in the forming process. So, it is necessary to study the influence of the flanging part width (W) and the stiffeners part height (H) of the T-section on springback. We set W to 15 mm and change the value of H value according to the real product. The value of springback increases with the increase of H value in the beginning. After ratio of H/W increases to 0.6, the value of springback fluctuates with the increase of H value. When ratio of H/W is about 0.5, the springback values are mostly less than ± 0.5 mm in key sections, which is acceptable.

Numerical simulation on dynamic response of flexible multi-body tower blade coupling in large wind turbine

Large scale wind turbine tower blade coupling belongs to nonlinear coupled vibration system, force changes will affect the stability of the system by the displacement and stress caused by the vibration, by joint simulation technology of multi parameter monitoring of large scale wind turbine tower blade coupling structure, with the response under different working conditions of the analysis, identified the need for improved structural parts the situation changes, the key components of multi parameter monitoring tower blade coupling structure with time, study on the influence of various parameters on the structure, put forward the improvement measures, and the structure of parts before and after improvement were analyzed comparing the dynamic stability of wind turbine, so as to provide reference for flexible multi-body system. Aiming at the dynamic response of large wind turbine flexible tower segments, a two-way fluid solid coupling method is used to analyze the fluid and structure dynamics of the flange at the segmental flange of the tower. Combined with the flow chart, the typical modal diagram of the flange is obtained. Considering the analysis of hydrodynamic coupling structure in the blade tower, in the combined effect of wind shear and fluctuating wind, the tower flange speed, pressure, shear stress and vorticity distribution, while considering the comparison of stress and displacement should be coupled with not considering the coupling effect of tower flange. The shear stress of the tower flange shows a nonlinear trend. The wind speed of the bolt uniformly distributed is stable. Considering the coupling effect, the flange amplitude of the tower flange is smaller than that without considering the coupling effect. The results can be used as a reference for monitoring the dynamic parameters of the flange structure under the coupling effect of the tower frame blade of a large wind turbine.

Low-Frequency Eddy-Current Testing for Detection of Subsurface Cracks in CF-188 Stub Flange

The vertical stub flanges on the CF-188 Hornet fighter aircraft are responsible for linking two vertical stabilizers to the fuselage. Repeated stresses due to dynamic loads on aircraft structure during flight may cause eyebrow cracks on the flange around fastener holes. Prevention of failure of the flange structure involves early detection before cracks grow to a critical length. Low-frequency eddy-current (LFEC) techniques have been applied to inspect thick conducting aircraft structures. However, in the case of the stub flange, LFEC is challenged by component geometry. In particular, the surface containing cracks is not parallel to the surface that is accessible for scanning. The bolts are perpendicular to the face with cracks but are almost at 85° to the scanning surface. A novel conical probe is designed to use the bolt as a core for the excitation (driver) coil, thereby increasing driving flux density, and to constrain probe positioning as it is swept around the bolt. Finite-element simulations are used to investigate influence of different parameters on LFEC impedance plane response. These include slope of the slanted surface, sample thickness, operating frequency, crack size, and edge effect for two different component edge shapes. Experimental measurements carried out at different frequencies on test samples, prepared with the same dimensions as actual flanges, were found to be in good agreement with computational models. Results indicate that LFEC is significantly affected by surrounding geometries, which therefore, need to be taken into account when inspecting for cracks.