Deformation Of Assembly Research Articles

Assembly deformation prediction of aircraft composite panel considering manufacturing variation and actual assembly process

Assembly deformation prediction of aircraft composite panel considering manufacturing variation and actual assembly process

The Self‐Calibrating Tilt Accelerometer: A Method for Observing Tilt and Correcting Drift With a Triaxial Accelerometer

AbstractWe present observations from two field deployments of a calibrated tiltmeter that we name the Self‐Calibrating Tilt Accelerometer (SCTA). The tiltmeter is based upon a triaxial quartz crystal accelerometer; the horizontal channels measure tilt and are periodically rotated into the vertical to obtain a measurement of the acceleration of gravity. Changes in the measured total acceleration are ascribed to drift in the vertical channel and used as calibrations for removing that same drift from the tilt time series observed between calibrations. Changes in the span (sensitivity) of the accelerometer channels can also be measured by calibrating them pointing up and down. A 3‐year test on the seafloor at Axial Seamount show that the calibrations are consistent with a linear‐exponential model of drift to a RMS residual of ∼0.5 μg (μrad). The calibrated tilt time series was impacted by platform settling for the first 2 years, but after repositioning the tiltmeter, the calibrated observations were consistent for the final year with the tilt observed on a nearby LILY tiltmeter, within an assumed level of drift for the unconstrained LILY sensor. A separate 15‐month test in a stable vault at Piñon Flat Observatory was complicated by seasonal temperature variations of >5°C; the calibrations are consistent with a linear‐exponential model of drift to ∼2 μg RMS when temperature and temperature time‐derivative dependence is included. Similarly, the calibrated tilt time series was impacted by thermal deformation of the SCTA assembly. A future test in a thermally and tectonically stable borehole will be required to assess the accuracy of the SCTA.

Modeling of CNC machine tool line rail assembly accuracy and its control method

Aiming at the linear guide assembly process, due to the preload load caused by the assembly deformation mechanism is not clear resulting in the guide assembly straightness is difficult to predict the problem. In this paper, based on the establishment of linear guide assembly deformation model, the ideal and actual conditions of the guide assembly deformation is discussed. Secondly, considering the influence of manufacturing error of the guide rail mounting surface on the guide rail assembly accuracy, it puts forward the integrated assembly deformation and manufacturing error of the guide rail assembly straightness error prediction model, and puts forward the control method of the guide rail assembly accuracy based on the assembly deformation and the inverse repair manufacturing error. Finally, the experimental bench is built and the accuracy of the theoretical model and accuracy control method is verified through experiments , and the results show that the straightness error of the guideway assembly is reduced by .

Steady Heat Transfer Analysis of the Refrigerator Seal Considering Rigid and Flexible Contact

The rigid and flexible contact of the refrigerator seal has a significant impact on its heat transfer characteristics, but existing research has ignored this important factor. In this paper, the assembly physical model at the seal region is established by static structural analysis. Then a three-dimensional heat transfer numerical simulation is carried out. The assembly distance affects the contact state of the seal by changing the contact position between the seal and the door or the cabinet. The calculation results show that the calculated temperature at the seal region considering the actual assembly deformation is closer to the measured temperatures. In the case study, the heat leakage load decreases by 18.57% and 19.99% at the compressed state, while it increases by 4.45% under the stretching state. The proportion of heat transfer load in the path of rubber strip-cold air and rubber strip-outer shell of the cabinet is the largest, reaching over 30.0%. The heat transfer load of the cold bridge also accounts for over 20.0%. When optimizing the seal structure, reducing the contact interface length of rubber strip-cold air, reducing thermal conductivity, and increasing the contact thermal resistance of cold bridge should be focused on.

Prediction method of long-term creep deformation of mobile phone resin lens module in a harsh temp environment

In recent years, the replacement cycle of digital products such as mobile phones in the market has significantly increased, and the accurate prediction of attenuation under long-term usage conditions of the lens module, storage, and other components has become important. The vast majority of mobile phone lens modules are processed from optical resins, and the degradation of their imaging performance is mainly caused by assembly deformation and long-term creep deformation after a high-temperature reliability test. Therefore, there is an urgent need for a reliable model to describe the long-term creep deformation of the mobile phone resin lens module in a harsh temperature environment. This study proposed a modified derivation method for the parameters of the Maxwell constitutive model to predict the long-term creep deformation of the mobile phone resin lens module in a high-temperature environment. The fitting accuracy of the modified generalized Maxwell model and the time-hardening model were compared through uniaxial compression creep experiments. Long-term creep simulations and experiments were conducted on the mobile phone resin lens module; the deformation law of each component of the mobile phone resin lens module was identified; and the creep deformation mechanism was elucidated. The result shows that the modified generalized Maxwell model has much higher accuracy than the time-hardening model in predicting the long-term creep deformation of different resin materials. When considering the influence of the creep phenomenon, the simulation result matches well with the experimental result, and the high-temperature creep mechanism of the mobile phone resin lens module was clarified. In addition, it was found that the maximum deformation of the lens occurred at the lens with the largest size, which was 2.1 µm, and the position with the largest surface deviation was at the edge of the lens. The prediction method proposed in this study can provide guidance and correction suggestions for the structural design of a mobile phone resin lens module and the rationality of optical design; thus, the imaging accuracy of lens modules will be guaranteed to the greatest extent possible.

Prediction of aircraft panel assembly deformation using a combined prediction model

Prediction of aircraft panel assembly deformation using a combined prediction model

The Effect of Implant Length and Bone Quality on the Biomechanical Responses of Dental Implant and Surrounding Bone – A Three-Dimensional Finite Element Analysis

The robustness of dental implant systems in the context of occlusal restoration relies significantly on biomechanical factors associated with the imposition of excessive loads. These factors encompass the macro geometries of the implants, bone qualities, parafunctional oral habits, and specific materials employed. The choice of different implant lengths in different bone qualities may give rise to distinct effects on the way loads are distributed across the interface between the implant and the adjacent bone. As of now, the influence of implant length and bone quality on the surrounding tissues and the stability of implant structure continues to be a matter of debate and uncertainty, particularly in situations involving the possibility of implant failure. This study employed three-dimensional finite element analysis to investigate five distinct implant lengths (4, 6, 10, 13, and 15 mm) in two types of bone quality (type II and III). The bone tissues were characterized through the utilization of computed tomography image datasets and then underwent processing within the SolidWorks software. All geometric configurations were transformed into finite element models, which were subjected to analysis within the ANSYS software. Anisotropic and isotropic properties were attributed to the bone and implant models, respectively. A dynamic occlusal loading quantified at 300 N was applied to the implant body, accompanied by a pre-tension force of 20 N on the screw component. The longer implants exhibited decreased stress magnitudes in type II bone (87.86 – 36.66 MPa) and increased stress magnitudes in type III bone (80.5 – 2128.9 MPa) within the surrounding bone tissue, in comparison to the shorter implants. However, stress within the implant body was generally elevated with the use of longer implants in both bone types (type II: 505.32 – 625.35 MPa; type III: 500.45 – 2186.7 MPa). Irrespective of bone quality, the longer implants predominantly led to lower bone strain levels (type II: 0.006828 – 0.003328; type III: 0.054250 – 0.021678) and overall deformation of the implant-abutment assembly (type II: 0.1458 – 0.1348 μm; type III: 0.1754 – 0.1492 μm) compared to their shorter counterparts. Among all the assessed findings, type III bone displayed a more pronounced adverse impact on the biomechanical responses of the dental implant and neighbouring bone except for the implant stresses under the applied physiological loading.

A coupled FEM-FFT concurrent multiscale method for the deformation simulation of CFRPs laminate

Carbon fiber reinforced polymer composites (CFRPs) laminate is increasingly used in aircraft structures and its assembly deformation has great influence on the aircraft aerodynamic profile and mechanical performance. Due to the inherent multiscale nature of CFRPs, the traditional macroscopic models are unable to incorporate their true microstructural details, resulting in them being unable to provide both the macro and micro deformations simultaneously. To address this issue, this work proposed a coupled FEM-FFT concurrent multiscale method for the deformation simulation of CFRPs laminate, where the mechanical response of each macro point of CFRPs laminate was from the corresponding unidirectional representative volume element (UD RVE). The FEM (Finite Element Method) was used for the analysis at the macroscopic scale, while the FFT (Fast Fourier Transform) based method was employed in the UD RVE to speed up the calculation. The elastoplastic behavior of resin matrix in the UD RVE was modelled with the parabolic yield criterion. The proposed concurrent multiscale method was validated respectively by the tension, compression and shearing experiments of CFRPs laminate. The results show that there is a good agreement both for the full strain field and load–displacement curve, demonstrating the effectiveness of the proposed concurrent multiscale method.

A computational framework for drop time assessment of a control element assembly under fuel assembly deformations with fluid-structure interaction and frictional contact

This paper presents a computational framework for drop time assessment of a control element assembly (CEA) under fuel assembly (FA) deformations. The proposed framework consists of three key components: 1) finite element modeling of CEA, 2) fluid-structure interaction to compute drag force, and 3) modeling of frictional contact between CEA and FA. Specially, to accommodate the large motion of CEA, beam elements based on absolute nodal coordinate formulation (ANCF) are adopted. The continuity equation is utilized to calculate the drag force, considering flow changes in the cross-sectional area during the CEA drop. Lastly, beam-inside-beam frictional contact model is employed to capture practical contact conditions between CEA and FA. The proposed framework is validated through experiments under two scenarios: free falls of CEA within FA, encompassing undeformed and deformed scenarios. The experimental validation of the framework demonstrated that the drop time of CEA can be accurately predicted under the complex coupling effects of fluid and frictional contact. The drop times of the S-shaped deformation case is longer than those of the C-shaped deformation case, affirming the time delay due to frictional force. The validation confirms the potential applicability to access the safety and reliability of nuclear power plants under extreme conditions.

A connecting rod assembly deformation cognition method based on quality characteristics probability network

As the core component of marine diesel engines, the connecting rod quality directly affects the reliability and life of diesel engines. However, the deformation problem of the connecting rod assembly process, which caused the low pass rate of one-time assembly, has not been well solved. The deformation of connecting rod assembly is difficult to analyze by mechanism because it is influenced by many quality characteristics with complex and cross-process correlations. To address this issue, this paper proposes a connecting rod assembly deformation cognition method based on the quality characteristics probability network. Firstly, a quality characteristics probabilistic network model for the connecting rod assembly process is established. Secondly, based on the quality characteristics probability network model and the complexity of cross-process correlation, the K-shell entropy weight model is used to identify the key quality characteristics and construct their correlation model. Then, to deal with the uncertainty of the influence degree between quality characteristics, a Bayesian network is used to establish an influence analysis model of key quality characteristics and analyze their influence relationship from qualitative and quantitative perspectives. Finally, the simulation and actual assembly data of marine diesel engine connecting rod assembly process are used to train and verify the cognition method. The results show that the method can effectively analyze the relationship between the connecting rod assembly process quality characteristics and predict the connecting rod deformation degree. The proposed method can comprehensively consider the influence of multiple processes and quality characteristics, improve the accuracy of analysis and prediction of connecting rod deformation, and can be used to guide the dynamic adjustment of the connecting rod assembly process to increase the pass rate of one-time. Moreover, the proposed method can also provide a reference for other multi-process and multi-factor problem analyses.

An illumination-robust edge detection method for nuclear fuel assembly deformation measurement

Fuel assemblies (FAs) are critical components of nuclear reactor cores. The excessive deformation of FAs can pose a serious risk of safety accidents in nuclear power plants. Hence, regular monitoring of the deformation of the FAs is necessary. To accomplish this task, the most critical challenge lies in accurately extracting the edges of FAs in the nuclear underwater environment with spatial variations in illumination. In this paper, a novel illumination-robust edge detection method is proposed. Firstly, tilt correction is applied to arrange the fuel rods vertically in the image. Then, the center of each fuel rod is located through grayscale projection and filtered by rod center spacing variance minimization. Subsequently, adaptive thresholding is employed to obtain a binary image. Finally, the edges are identified by searching in the vicinity of rod centers in the binary image. The effectiveness and robustness of the proposed method have been validated in experiments, and the approach has been successfully applied to the FA deformation measurement in nuclear power plants.

A tolerance analysis method based on assembly deformation simulation with stable contact

PurposeThe assembly simulation in tolerance analysis is one of the most important steps for the tolerance design of mechanical products. However, most assembly simulation methods are based on the rigid body assumption, and those assembly simulation methods considering deformation have a poor efficiency. This paper aims to propose a novel efficient and precise tolerance analysis method based on stable contact to improve the efficiency and reliability of assembly deformation simulation.Design/methodology/approachThe proposed method comprehensively considers the initial rigid assembly state, the assembly deformation and the stability examination of assembly simulation to improve the reliability of tolerance analysis results. The assembly deformation of mating surfaces was first calculated based on the boundary element method with optimal initial assembly state, then the stability of assembly simulation results was assessed by the density-based spatial clustering of applications with noise algorithm to improve the reliability of tolerance analysis. Finally, combining the small displacement torsor theory, the tolerance scheme was statistically analyzed based on sufficient samples.FindingsA case study of a guide rail model demonstrated the efficiency and effectiveness of the proposed method.Research limitations/implicationsThe present study only considered the form error when generating the skin model shape, and the waviness and the roughness of the matching surface were not considered.Originality/valueTo the best of the authors’ knowledge, the proposed method is original in the assembly simulation considering stable contact, which can effectively ensure the reliability of the assembly simulation while taking into account the computational efficiency.

Enhancement of virtual data quality using pre-trained Bayesian transfer learning under inaccurate and insufficient measurement data

The accurate application of designed dimensions in manufacturing is crucial but complicated by certain limitations in the manufacturing process. Therefore, manufacturing and assembly conditions should be considered in product designs. However, predicting and managing the deformation quality of industrial products, composed of multiple components, is often challenging owing to part deformation during the manufacturing process and structural deformation at the assembly stage. Owing to the advancements in artificial intelligence, highly precise predictive models can be created if sufficient data are available. However, the acquisition of extensive labeled data required for model training can be expensive and time-consuming in the industrial sector. Traditional approaches such as computer-aided engineering, which are commonly used to produce virtual data, have limitations owing to uncertainties in the experimental data, making consistency correction both time-consuming and expensive. This study proposes a method for enhancing the quality of virtual data created in contexts with insufficient and inaccurate experimental data. Engineering properties were extracted from experimental data and integrated with transfer learning using a pre-trained Bayesian neural network. We applied the proposed method to a micro-LED case to predict assembly and manufacturing variations during the design phase under inaccurate and insufficient data. Consequently, the accuracy was significantly improved over the predictive model that predicted the amount of assembly deformation using only experimental data, resulting in a predictive model with an average R-squared prediction accuracy of 98.9% for the deformation resulting from the assembly.

Experimental Investigation of Control Rod Drops Into Perturbed Fuel Assemblies

Abstract This paper discusses permanent deformation of the fuel assembly of pressurized water reactors that have to satisfy a drop time requirement of the control rod assembly. During a seismic event, the fuel assemblies and the reactor core exhibit transient vibration. When the fuel assemblies collide, they develop impact forces in the spacer grids along the fuel assemblies. If the impact forces on some spacer grids of the fuel assembly exceed an allowable strength, the buckling occurs in the corresponding spacer grids, followed by permanent deformation. The geometry change of the buckled spacer grids leads to the movement of the guide tube positions in the fuel assembly. Therefore the geometry change is associated with the distortion of the control rod drop path. In this study, the permanent deformation of the spacer grids was measured during the impact tests, and the maximum deviation of the guide tube from the original position was investigated. Control rod drop tests were also performed to measure the change in drop time according to the deformation of the fuel assembly. Using actuators in the loop test facility, the authors realized the first and second bending mode shapes of the fuel assembly under the flowing water condition. Based on a series of drop tests, the critical fuel assembly deformation was identified that could lead to a violation of an allowable drop time of the control rod.

Study on temperature field and deformation field of AMT dry clutch assembly under continuous slip grinding

In this paper, Ansys finite element analysis was used to study the temperature and deformation fields of clutches after continuous slip grinding for the 30s, 45s, and 60s, under different constraints on the pressure plate, and after cooling to room temperature. Its sliding time is extended while cooling the clutch from the highest temperature to the initial temperature through a certain setting, and then its temperature field and deformation field are analyzed at different sliding times after cooling. Through this study, we can explore the performance of this clutch under extremely harsh working conditions, to analyze whether it meets the standard of use of the corresponding car or makes corresponding optimization improvements.As the sliding time increases, the maximum temperature of the clutch rises, and the temperature is transmitted to the inner and outer diameters centered on the sliding surface. As the temperature generated by continuous sliding grinding continues to rise, the deformation of the clutch assembly also increases, and when the temperature drops, the clutch will quickly reduce a certain amount of deformation in a short period and then gradually return to its original shape. The higher the temperature, the more likely the clutch is to deform. When the temperature is at a lower value, its ability to deform and its rebound performance will also decrease.

Performance analysis of avionics devices based on electro-thermal-stress multi-physics coupling under immersion cooling

The present study aims to analyze immersion cooling for the work reliability enhancement of avionics devices based on electro-thermal-stress multi-physics simulation. A comprehensive performance indicator considering the maximum DC IR-drop of the power supply network (PDN), the maximum temperature of the electronic elements and the maximum deformation of the printed circuit board (PCB) assembly is constructed to evaluate the effect of different flow distributor structure styles and Reynolds number (Re) on the work reliability of avionics devices. The results show that the maximum DC IR-drop of 2.0 V PDN was 73.83 mV which was the largest value among 1.5 V, 2.0 V, 3.3 V and 5.0 V PDN. The DC IR-drop of design A, design B and design C was smaller than the supply voltage fluctuation in a real design, this indicates that the flow distributor has no significant effect on enhancing the power delivery capability of PDN. The reflow in the middle part of design C makes the average temperature of PCB assembly lower than that of design A and design B by about 1–3 °C. The flow distributor has a significant effect on the maximum temperature of electronic elements and the pressure drop of avionics devices with Re increase, but not viable to decrease the maximum deformation of PCB assembly for design A and design B. The minimum of comprehensive evaluation function f is 0.038 when Re = 43,000 for design C, this means the comprehensive working reliability of the avionics server module is the best. Due to different flow patterns, the average temperature of PCB assembly for design C was lower which improve the electrical and mechanical properties, thus the value of f for design C was always smaller than that of design A and design B. The method and results herein revealed the advantages and potential limitations of immersion cooling on the working reliability of the avionics devices.

Effect of forced assembly on bearing performance of single-lap, countersunk composite bolted joints – Part Ⅰ: Experimental investigation

This paper presented an experimental study on the effect of forced assembly on bearing performance of single-lap, countersunk composite bolted joints. The forced assembly deformation amounts in bearing tests were chosen according to the acoustic emission (AE) damage detection results of the bending test. 3D digital image correlation (DIC) technology was used to measure out-of-plane deformation and surface strain field. Bearing damage was observed through microscopy after bearing tests. It is found that forced assembly causes pre-tension as well as higher loading eccentricity, thus obviously weakening the effective bearing strength of single-lap, countersunk composite joints. Specimens with forced assembly display S-shape out-of-plane bending under effective tensile loading. The damage degree of the non-countersunk hole is close to that of the countersunk hole, which indicates that forced assembly uniformizes bearing load distribution at countersunk hole while aggravates the non-uniformity of bearing load distribution at the non-countersunk hole.

Photoresponsive reversible self-assembly of rod-coil amphiphiles containing spiropyran groups.

Stimuli-responsive assembly deformation is a key feature in constructing smart soft materials, which makes them versatile and autonomous. In this study, rod-coil amphiphilic compounds containing spiropyran (SP) groups were developed and synthesized to investigate their stimuli-responsive assembly in a solution system with 99% water content. In addition to photochromic phenomena, reversible light-mediated morphological alterations occurred in these molecular aggregates. Based on the different flexible chain segments of rod-coil amphiphiles, the initial assemblies underwent a dissociation-reassembly process under ultraviolet (UV) irradiation, whereupon they deformed or disassembled to assemblies. Furthermore, as the UV source was removed, the original nanostructures were gradually recovered again via the ring-closing reaction process. These compounds, interestingly, can selectively combine with copper ions to produce cross-linked co-assembled nanostructures. The copper ion complex solution of rod-coil amphiphilic compounds emitted unique bright blue fluorescence, which allowed for the specific visual identification of copper ions in aqueous solutions.

Thermo-mechanical stress modeling and experimental investigation on micro-cracks in tilling ribbon photovoltaic modules during lamination and mechanical load test

Photovoltaic (PV) module failures due to silicon cell cracking are gaining more and more attention. It is found that Ethylene Vinyl Acetate (EVA) is one of the most significant contributions to reduce failures resulting from the fracture of silicon solar cells. In this work a full understanding of the impact of lamination and external mechanical loads on the cracking of newly developed tilling ribbon (TR) mono-crystalline modules (encapsulated with a Zebra-EVA), and the direct impact of micro-cracks on the module power after mechanical load test, has been developed. Finite element modelling (FEM) is used to predict the temperature and stress distribution inside each layer and the surface deformation of the PV assembly in the encapsulation, as well as the accumulated stresses of the PV module under mechanical loads. Comparing to the conventional PV module, a TR module was found to have significantly enhanced efficiency by 1.5% with an increased power of more than 20 W. Compared to the conventional EVA layer, Zebra-EVA could reduce the probability of micro-cracks by 3.6% during lamination and effectively decrease the mechanical stress imposed on silicon cells when the module is exposed to external mechanical conditions, offering a lower cracking risks and less power losses, which agreed with the simulation results. It is shown that conversionefficiency of a PV module is improved through TR technique, while its lamination-induced cracking and the failure probability induced from mechanical loading can be efficiently reduced by utilizing Zebra-EVA encapsulate.

Interfacial Assembly and Jamming of Soft Nanoparticle Surfactants into Colloidosomes and Structured Liquids.

Nanoparticle surfactant (NPS) offers a powerful strategy to generate all-liquid constructs that integrate the inherent properties of the NPs into 3D architectures. Here, using the co-assembly of fluorescent polymeric nanoparticles and amine-functionalized polyhedral oligomeric silsesquioxane, the assembly and jamming behavior of a new type of NPS at the oil-water interface is uncovered. Unlike "solid" inorganic nanoparticles, "soft" polymeric nanoparticles can reorganize when jammed, leading to a relaxation and deformation of the interfacial assemblies, for example, the 3D printed sugar-coated haw stick-like liquid tubules. With NPS serving as emulsifiers, stable Pickering emulsions are prepared that can be converted into robust colloidosomes with pH responsiveness, showing numerous potential applications for encapsulation and controlled release.