Thermal Deformation Analysis Research Articles

Direct energy deposition for smart micro reactor

ABSTRACT Nuclear microreactors (MRs) have attracted significant attention for their versatility in installation locations, especially with the growing demand for sustainable green energy in large data processing facilities. However, ensuring their safe operation necessitates frequent inspections, which can be challenging for practical efficient management. This study proposes a novel approach using direct energy deposition to incorporate an optical fiber sensor into MR components, enabling real-time monitoring with artificial intelligence. The embedded optical fiber generates real-time data that allows for AI-driven in-vivo thermal deformation analysis. Our smart MR component can detect structural anomalies, identify abnormal operations, and assess operational conditions through augmented reality interfaces and AI technology.

Coupled field modelling of thermomechanical response in materials using peridynamic heat transport model and non-ordinary state-based peridynamics

Predicting the mechanical response of materials subjected to transient heat processes is crucial in various engineering applications. This paper introduces a novel peridynamic (PD) coupled field model formulated within the framework of Non-Ordinary State-Based Peridynamics (NOSBPD). This model offers the capability to simulate the coupled thermo-mechanical behavior of materials by incorporating both thermal transport and mechanical deformation analyses. To verify the model’s accuracy, a benchmark problem involving a steel plate undergoing transient thermal expansion is investigated. This model presents a valuable tool for various engineering applications involving coupled thermo-mechanical processes.

Analysis of thermal residual deformation using different FVFs for each ply

The thermal stresses and residual deformations in composite materials are caused by differences in the thermal expansion coefficients between the fiber and matrix, chemical shrinkage of the matrix, and temperature distribution during curing. Complex thermal stresses can cause residual thermal deformations, including spring-in, spring-out, and warpage. Consequently, modifying composite molds is time-consuming and labor-intensive.In this study, composite laminate plates were fabricated using the VARTM and VIP processes. For each ply, thermal deformation analysis using different FVFs was performed, and the results were compared with the experimental results. The analysis error of the thermal residual deformations using various FVF for each ply was 9.9–36.1%, which was lower than that using the uniform FVF for all plies. Additionally, the residual thermal deformations caused by the VIP process were smaller than those caused by the VARTM process.

Analysis and Experiment of Thermal Field Distribution and Thermal Deformation of Nut Rotary Ball Screw Transmission Mechanism

This study designs a differential dual-drive micro-feed mechanism, superposing the two “macro feed motions” (“motor drive screw” and “motor drive nut”) using the same transmission of “the nut rotary ball screw pair” structure. These two motions are almost equal in terms of speed and turning direction, thus the “micro feed” can be obtained. (1) Background: Thermal deformation is the primary factor that can restrict the high-precision micro-feed mechanism and the distribution of heat sources differs from that of the conventional screw single-drive system owing to the structure and motion features of the transmission components. (2) Discussion: This study explores the thermal field distribution and thermal deformation of the differentially driven micro-feed mechanism when two driving motors are combined at different speeds. (3) Methods: Based on the theory of heat transfer, the differential dual-drive system can be used as the research object. The thermal equilibrium equations of the micro-feed transmission system are established using the thermal resistance network method, and a thermal field distribution model is obtained. (4) Results: Combined with the mechanism of thermal deformation theory, the established thermal field model is used to predict the axial thermal deformation of the differential dual-drive ball screw. (5) Conclusions: Under the dual-drive condition, the steady-state thermal error of the nut-rotating ball screw transmission mechanism increases with the increase in nut speed and composite speed and is greater than the steady-state thermal error under the single screw drive condition. After reaching the thermal steady state, the measured thermal elongation at the end of the screw in the experiment is approximately 10.5 μm and the simulation result is 11.98 μm. The experimental measurement result demonstrates the accuracy of the theoretical analysis model for thermal error at the end of the screw.

Piston structure design and finite element analysis

The working characteristics of internal combustion engines rely on the explosive combustion of fuel in the combustion chamber to drive the piston movement. This working characteristic causes the main component of the combustion chamber, the piston, to bear high thermal and mechanical loads. It has very high requirements for design, manufacturing, and material selection. The working condition of the piston will affect its safety and stability. Therefore, the finite element analysis for the piston is particularly important. Thus, this article first establishes the piston model and divides it into grids in ANSYS, adds boundary conditions, and conducts analysis. The piston thermal analysis mainly includes thermal stress and deformation analysis under thermal load. The piston’s maximal thermal stress is 170.23 MPa and the deformation of thermal expansion is 0.61585 mm. The mechanical stress and deformation analysis under mechanical load are carried out. The maximal stress is 164.91 MPa and the maximal deformation caused by the mechanical stress is 0.24916 mm. Finally, the coupling analysis of thermal and mechanical stress is conducted. The maximal stress is 251.74 MPa, which is located at the outskirt margin of the piston pinhole. The maximal deformation is 0.60779 mm. The simulation analysis results indicate that the method proposed in this article provides a way to design the structure of similar automotive components such as pistons.

Optimizing ageing conditions for commercial NiTi archwires: Insights from thermal phase transformation and tensile deformation analysis

Superelastic nickel-titanium (NiTi) archwires are now commonly used as the standard archwire during the orthodontic alignment and levelling stage. They are preferred due to their ability to apply minimal force on teeth while allowing for a wide range of tooth movements. During orthodontic treatment, the orthodontist assesses the dimension and shape of the NiTi archwire to determine the amount and direction of force required to align misaligned teeth. The main contribution of this study is the parametric analysis and establishment of a set of optimal ageing temperatures and duration for the investigation of functionally graded nickel-titanium archwire using differential scanning calorimetry (DSC) and tensile deformation testing. The mechanical and thermal phase transformation behavior after ageing at six temperatures for duration of 15 minutes have been investigated using tensile deformation test and differential scanning calorimetry (DSC) test in this paper. Experimental results reveal that in thermal analysis as the ageing temperatures increase from 400 °C to 490 °C, the austenite finish temperature rises to a value between 9.53 °C and 35.48 °C, and subsequently decreases to 520 °C. The archwire specimen aged for temperature of 490 °C exhibited the austenite finish temperature of around 35.48 °C, and it is highest among the aged wire specimens closest to oral temperature. In tensile deformation, the ideal ageing temperature for orthodontic applications was determined to be 490 °C for 15 minutes, resulting in relatively low plateau slope 13.73 GPa with high superelatic ratio 12.04, and maximum plateau strain of 7 %.

A Novel Temperature Drift Error Estimation Model for Capacitive MEMS Gyros Using Thermal Stress Deformation Analysis.

Because the conventional Temperature Drift Error (TDE) estimation model for Capacitive MEMS Gyros (CMGs) has inadequate Temperature Correlated Quantities (TCQs) and inaccurate parameter identification to improve their bias stability, its novel model based on thermal stress deformation analysis is presented. Firstly, the TDE of the CMG is traced precisely by analyzing its structural deformation under thermal stress, and more key decisive TCQs are explored, including ambient temperature variation ∆T and its square ∆T2, as well its square root ∆T1/2; then, a novel TDE estimation model is established. Secondly, a Radial Basis Function Neural Network (RBFNN) is applied to identify its parameter accurately, which eliminates local optimums of the conventional model based on a Back-Propagation Neural Network (BPNN) to improve bias stability. By analyzing heat conduction between CMGs and the thermal chamber with heat flux analysis, proper temperature control intervals and reasonable temperature control periods are obtained to form a TDE precise test method to avoid time-consuming and expensive experiments. The novel model is implemented with an adequate TCQ and RBFNN, and the Mean Square Deviation (MSD) is introduced to evaluate its performance. Finally, the conventional model and novel model are compared with bias stability. Compared with the conventional model, the novel one improves CMG's bias stability by 15% evenly. It estimates TDE more precisely to decouple Si-based materials' temperature dependence effectively, and CMG's environmental adaptability is enhanced to widen its application under complex conditions.

A fractional dual-phase-lag thermoelastic model for a solid half-space with changing thermophysical properties involving two-temperature and non-singular kernels

<abstract> <p>The thermal and mechanical properties of materials show differences depending on the temperature change, which necessitates consideration of the dependence of the properties of these materials on this change in the analysis of thermal stress and deformation of the material. As a result, in the present work, a mathematical framework for thermal conductivity was formulated to describe the behavior of non-simple elastic materials whose properties depend on temperature changes. This derived model includes generalized fractional differential operators with non-singular kernels and two-stage delay operators. The fractional derivative operators under consideration include both the Caputo-Fabrizio fractional derivative and the Atangana-Baleanu fractional derivative, in addition to the traditional fractional operator. Not only that, but the system of governing equations includes the concept of two temperatures. Based on the proposed model, the thermodynamic response of an unlimited, constrained thermoelastic medium subjected to laser pulses was considered. It was taken into account that the thermal elastic properties of the medium, such as the conductivity coefficient and specific heat, depend on the temperature. The governing equations of the problem were formulated and then solved using the Laplace transform method, followed by the numerical inverse. By presenting the numerical results in graphical form, a detailed analysis and discussion of the effects of fractional factors and the dependence of properties on temperature are presented. The results indicate that the fractional order coefficient, discrepancy index, and temperature-dependent properties significantly affect the behavior fluctuations of all physical domains under consideration.</p> </abstract>

Research on high-precision digital image correlation measurement techniques for highly stable structures

Abstract This study proposes a novel digital image processing system that combines a diffraction-limited resolution (DLRF)-based measurement technique with a windowed form-center tracking algorithm. To evaluate the accuracy of this system, this paper compares and analyzes the effectiveness of conventional digital image techniques and DLRF-based methods for deformation displacement measurements. In addition, the study includes thermal stability tests under ambient noise and uniform high temperature conditions to evaluate the stability performance of the system in a complex environment. The experimental results show that the DLRF-based digital image correlation method proposed in this study performs well in reducing the mean deviation (from a maximum of 5.17 × 10-3 to 1.73 × 10-3) and root-mean-square error (from a maximum of 5.14 × 10-3 to 0.75 × 10-3). It is worth noting that the DLRF method is faster in processing when using the single-precision format than the double-precision format, with a speedup of up to 1.05 times. In addition, the multiple displacement averaging processing method can effectively filter the noise in the test, and the noise effect is only in the range of 0 to 2 μm in most areas. In the analysis of test points 10-34 and 57-80, the displacement error is controlled within 5 μm, indicating that the modified structural analysis model can be used for on-orbit micrometer-scale thermal deformation analysis. The study proves the high accuracy and stability of the digital image system proposed in this paper in the measurement of deformation displacement, which provides adequate technical support for accurate measurement in related fields.

Thermal and Structural Performance Analysis of Piezoelectric Acceleration Sensor

Thermal and structural piezoelectric acceleration sensors are complicated and affected by many factors, especially when the sensor works in different temperature environments, its performance and structure will be affected to some extent. In this paper, the interference contact model of piezoelectric sensor is established with the method of bolt preloading, and the finite element analysis is carried out under different interference quantities. Moreover, based on the bolt preload model, the loading method of temperature load is studied, and the structural thermal adaptation characteristics of the sensor under the conditions of -70℃, -50℃, 0℃, 120℃, 160℃ and 200℃ are analyzed. Based on these thermal deformation and thermal stress analysis at different temperatures, the thermal adaptation characteristics of the sensor are analyzed. The normal operating temperature range of the sensor is -50℃ -120 ℃, and the structural parameter of the sensor (the thickness of the base) is optimized, so that the operating temperature of the sensor can reach 200℃. Ability to analyze.

Structural Enhancement and Thermal Deformation Analysis of Antenna Arrays in Vehicle-Mounted Phased Array Radar: A Heat Dissipation Perspective

Structural Enhancement and Thermal Deformation Analysis of Antenna Arrays in Vehicle-Mounted Phased Array Radar: A Heat Dissipation Perspective

Thermal deformations analysis of large-scale vertical Lathe

This article presents an analysis of thermal deformations in a large-scale vertical Lathe, examining the sources of heat and their impact on the machine’s thermal deformations. The analysis was conducted using both experimental measurements and numerical simulations based on the finite element method. The study highlights the critical role of geometric accuracy, stiffness, and thermal distortions in machine tool design, affecting machining errors. Several machine tool manufacturers implement systems that minimize the impact of thermal distortions using numerical control. However, custom production lacks extensive possibilities, posing challenges in achieving requirements for predictable thermal distortions. This article analyzes the thermal distortions of a custom-produced machine tool and examines their values and consistency with the machine tool’s working components’ movement. The study emphasizes the predictability and directionality of thermal distortions in large-sized machine tools to maintain geometric accuracy and stiffness. Additionally, the study identifies non-technical aspects related to the division of the worktable into component parts, disrupting the axial symmetry of the construction and causing potential deformations of the workpiece due to thermal deformations.

Improved Accuracy of Prediction of Thermal Deformation of the Stern Shaft Block Considering the Erection Process

Thermo-elasto-plastic analysis using nonlinear finite element analysis is used for predicting welding-induced structural deformation; however, its application in the prediction of welding deformation in large structures, such as ships and offshore plants, is practically impossible. Therefore, in this study, an inherent strain-based thermal deformation analysis method, which can be applied to large structures, was developed; furthermore, the inherent strain-based analysis was used for predicting the welding deformation occurring during block erection welding. However, although the tendency is somewhat similar in terms of quality, it still differs from the actual measured value in terms of quantity. In this study, a regression equation was derived by analyzing the sensitivity of the variables used in the existing method, and, subsequently, the results corresponding to the measured values were obtained; finally, the accuracy improvement for the three ships was confirmed. Therefore, using the proposed method, it is possible to improve the technology of predicting and controlling hull deformation.

Net-HDMR Metamodeling Method for High-Dimensional Problems

Abstract Metamodel technology provides an efficient method to approximate complex engineering design problems. However, the approximation for high-dimensional problems usually requires a large number of samples for most traditional metamodeling methods, which leads to the difficulty of “curse of dimensionality.” To address the aforementioned issue, this paper presents the Net-high dimension model representation (HDMR) method based on the Cut-HDMR framework. Compared with traditional HDMR modeling, the Net-HDMR method incorporates two novel modeling approaches that improve the modeling efficiency of high-dimensional problems. The first approach enhances the modeling accuracy of HDMR by using the net function interpolation method to decompose the component functions into a series of one-dimensional net functions. The second approach adopts the CV-Voronoi sequence sampling method to effectively represent one-dimensional net functions with limited samples. Overall, the proposed method transforms complex high-dimensional problems into fitting finite one-dimensional splines, thereby increasing the modeling efficiency while ensuring approximate accuracy. Six numerical benchmark examples with different dimensions are examined to demonstrate the accuracy and efficiency of the proposed Net-HDMR. An engineering problem of thermal stress and deformation analysis for a jet engine turbine blade was introduced to verify the engineering feasibility of the proposed Net-HDMR.

Thermal Deformation Stability Optimization Design and Experiment of the Satellite Bus to Control the Laser Communication Load’s Acquisition Time

The optical axis angle fluctuation due to thermal deformation of the satellite bus between the laser communication load and the star sensor must be constrained to within 0.16 mrad to meet the rapid acquisition needs of the laser communication satellite. This paper analyzes the satellite’s in-orbit temperature field distribution, which is then used as the input boundary condition for the thermal deformation analysis. The optical axis angle fluctuation is reduced by the common reference optimization design. Then, adaptable isolation between the satellite bus structure and the reference support structure reduces the thermal deformation coupling. As a result, there will be less optical axis angle fluctuation caused by thermal deformation. The thermal deformation between the optimized laser communication load and the star sensor installation angle is decreased to 14.25″ according to the entire satellite simulation analysis of the modified structure. The maximum angle variation induced by temperature change dropped from 117.74″ to 10.72″ through the ground temperature deviation and prism calibration tests. The on-orbit alignment test confirms that the required capture time of 30 s is met. The aforementioned work minimizes the uncertain region of laser communication load, lessens the in-orbit acquisition time, and satisfies the demand for speedy acquisition.

Thermal deformation and economic analysis of a multiobject cooling system for spindles with varied coolant volume control

Thermal deformation and economic analysis of a multiobject cooling system for spindles with varied coolant volume control

Clearance distribution design and thermal deformation analysis of variable-pitch screw rotors for twin-screw vacuum pumps

Clearance distributions between a pair of intermeshing screw rotors greatly affect the gas leakage and pump performance of twin-screw vacuum pumps. Screw rotors generated by the traditional clearance design method have unreasonable clearance distributions and then affect the vacuum degree, especially for variable-pitch screw rotors. Aiming at solving the above problem, this paper presented a novel clearance design method, and designed a pair of intermeshing variable-pitch screw rotors with reasonable clearance distributions at each meshing surface. In addition, thermal deformations of intermeshing screw rotors were simulated, and variations of each clearance were analyzed. Two kinds of screw rotors, the novel and traditional screw rotors, respectively designed by the novel and traditional clearance design methods were manufactured, and their ultimate vacuum degrees of two corresponding twin-screw vacuum pumps were tested. It is found that clearance distributions of the novel screw rotor are superior to the traditional screw rotor designed by the traditional method; the novel screw rotor reduces the value of the reserved circumferential clearance by 41.67%, and the corresponding twin-screw vacuum pump with this screw rotor achieves a higher ultimate vacuum degree as 0.1Pa, while the pump with the traditional screw rotor just achieves the value of 8.4Pa.

MOOSE Reactor Module: An Open-Source Capability for Meshing Nuclear Reactor Geometries

The U.S. Department of Energy (DOE) Nuclear Energy Advanced Modeling and Simulation (NEAMS) program has developed numerous physics solvers utilizing the open-source Multiphysics Object-Oriented Simulation Environment (MOOSE) framework for multiphysics reactor analysis. These solvers require input finite element meshes representing the discretized spatial domain. Typically, reactor analysts turn to licensed tools for the creation of reactor geometry meshes. Recently, open-source functionality has been added to the MOOSE framework to mesh common reactor geometries and improve MOOSE-based nuclear reactor application user workflows. The new functionality is primarily contained in the new Reactor module of MOOSE and includes support for hexagonal pins, assemblies, and cores, extended Cartesian geometry support, options for modeling static and rotating control drums within a hexagonal assembly, core periphery triangulation, and automatic tagging of pin, assembly, plane, and depletion regions for easier post processing of physics results. A set of reactor geometry mesh builder objects further streamlines the construction of hexagonal and Cartesian cores and allows mapping of materials to regions during mesh generation. The meshes produced with the MOOSE Reactor module may be used directly within MOOSE-based applications or exported as Exodus II files for use in other finite element solvers. The tools have been demonstrated and verified using a variety of NEAMS physics solvers on a range of reactor applications, including a sodium-cooled fast reactor core analysis using Griffin, a fast reactor assembly thermal deformation analysis using MOOSE Tensor Mechanics, and a heat pipe–cooled microreactor coupled analysis using Griffin, Bison, and Sockeye. MOOSE’s Reactor module provides significant advantages compared to the use of external meshing tools when analyzing Cartesian and hexagonal reactor lattices using MOOSE-based applications: immediate accessibility (open-source) to the end user, low barrier to entry for new users, speed of mesh generation, volume preservation of meshed fuel pins, and simplification of analysis workflow when used in conjunction with MOOSE-based applications.

Measurement and Analysis of Thermal Deformation of Wireless Charger PCB due to Heat

Measurement and Analysis of Thermal Deformation of Wireless Charger PCB due to Heat

Developing the AM G-code based thermomechanical finite element platform for the analysis of thermal deformation and stress in metal additive manufacturing process

Developing the AM G-code based thermomechanical finite element platform for the analysis of thermal deformation and stress in metal additive manufacturing process