Ceramic Core Research Articles

Hot ceramic lithography of silica-based ceramic cores: The effect of process temperature on vat-photopolymierisation

An enhanced-temperature vat photo-polymerisation of ceramic-loaded mixtures, or so called hot ceramic lithography, has been presented in this paper, for 3D printing silica-based ceramic cores used in the investment casting of hot section parts in aero and industrial turbines. The pre and post-sintering properties of the 3D printed ceramic parts highly depend on the polymerisation degree of the base resin binders and the rheological behaviour of ceramic slurry, and hot lithography can play a significant role both. First, the paper aimed to better understand how different printing temperatures (25,35,45 and 55 °C) would affect the properties of the base binder mixtures before loading ceramic particles, by conducting tensile, DMA and FTIR analysis on binder-only prints. The impact of elevated printing temperature on the mechanical properties of ceramic loaded binder mixtures was further investigated. The highest mechanical properties for the base binder and the ceramic loaded mixtures were achieved when the process temperature was set closer to the binder mixtures' initial glass transition temperature (when the binder is cured at room-temperature). This printing temperature is yet lower than the level causing heat-induced cross-linking yet high to enhance the mobility of monomers and active species, when compared with conventional room-temperature vat photopolymerisation printing. The results indicate that printing temperature, if set as described, can significantly impact the mechanical property of parts and conversion rate of the base binders for a successful print process. The second part of this study investigates the impact of temperature on the rheological behaviour and peeling forces of highly loaded ceramic-loaded mixtures (61.2 vol% of SiO 2 -ZrSiO 4 ). The suspension showed shear thickening behaviour at 25 °C, hindering the replenishment of the slurry during printing, while a high transition from shear-thickening to shear-thinning behaviour, ideal for flawless ceramic 3D printing, was observed at an optimum process temperature of 35 °C. When print temperature increases to 45 °C and then 55 °C, the viscosity of the mixture at very low shear rate (when the material is static during printing) increases, hence affecting peeling forces. Comparing peeling force measurements and FTIR results showed the higher cross-linking density, and the reactivity of the base binder, leads to a stronger adhesion between the cured layers and the printer's transparent film, hence higher separation/peeling forces. To sum up, hot ceramic lithography at the right printing temperature can resolve many print and post print issues, such as deformation and cracking, leading to a stronger and more dimensionally-accurate ceramic components.

Simulation of the High Temperature Test Facility (HTTF) Core Using the 2D Ring Model with SAM

A two–dimensional ring model is developed with SAM to model the core of the High Temperature Test Facility (HTTF) at the system level. The ring model simplifies the complex structure of the HTTF core by converting the hexagonal rows of heaters and flow channels into layers of concentric annular rings. The ring model is first compared against a three–dimensional (3D)–one–dimensional (1D) model where the solid structures are fully resolved in three dimensions while the fluid structures are modeled as 1D flows. Comparison between the 3D–1D and the ring models shows that the latter can predict major parameters reasonably well under steady–state normal operating conditions, but the heater temperatures are under predicted. Adjustment is made to the effective thermal conductivity of the ceramic core of the ring model to improve the heater temperature predictions. The ring model is also used to simulate a transient pressurized conduction cooldown condition and is benchmarked with the experimental data from the HTTF Test PG–27. Good agreement is obtained between the experimental data and the predictions by the ring model.

Sandwich-structural ionogel electrolyte with core–shell ionic-conducting nanocomposites for stable Li metal battery

Ionogel electrolytes (IGEs) containing ionic liquids as the unique liquid component can guarantee high ionic conductivity, wide electrochemical window, and high thermal stability simultaneously for developing stable and safe Li metal batteries, yet suffer from relatively low Li+ transference. In this work, ceramic ionic conductor-metal organic framework (MOF) core–shell nanocomposites are introduced as active matrix to fabricate a reinforcement layer with a high mechanical modulus. The ceramic core provides Li+ conduction pathway and the MOF shell possesses open pores and metal sites for ionic selectivity. Beyond this, the reinforcement layer is sandwiched by two buffer layers with a flexible polymer matrix to improve the interface compatibility and wettability with electrodes. Here, the nanocomposites powder can be synthesized through solid sintering followed by facile in-situ solution growth, promising the scalable production and practical application of the IGEs. As a result, the sandwich-structural IGE shows a high ionic conductivity of 3.87 × 10−4 S cm−1 at 25 ℃, wide electrochemical window (up to 5.2 V vs Li/Li+), and high thermal stability. The full cell (LiCoO2cathode) maintains 97.9 % capacity after 500 cycles at 0.2 C.

Sample selection for models to represent ceramic cores fabricated by stereolithography three-dimensional printing

In this study, ceramic cores were fabricated by stereolithography three-dimensional printing (SLA-3DP) with excellent synthetic mechanical properties. To this end, green body samples were first three-dimensionally printed in three models, after which the samples were sintered at different temperatures. High-temperature flexural strengths of the ceramic core samples printed in model 2 reached a maximum value of 24.2 MPa at a sintering temperature of 1250 °C during casting heat test at 1550°C. Meanwhile, the high- and room-temperature flexural strengths of ceramic core samples printed in model 2 were much stronger than those printed in models 1 and 3. Moreover, shrinkage, porosities, bulk densities and phase compositions of ceramic core samples printed in three models at different sintering temperatures did not show obvious differences. The ceramic core samples showed distinct mechanical properties as they had different fracture modes. We call this the “surface effect”. The anisotropy flexural strength was induced by weak binding between layers. The recommended choice of sample for different models to represent ceramic cores fabricated by stereolithography three-dimensional printing is model 2. Herein, based on the results of systematic characterization of high-throughput samples, we report the basic research, evaluation and prediction system of composition design, process optimization, microstructure and property defect analysis of ceramic cores made of SLA-3DP.

The effect of additives on properties of silica-based ceramic cores utilised in fabrication of multivane clusters for turbofan jet engine

Ceramic cores for mapping internal cooling channels in multivane clusters for turbofan jet engine must satisfy rigorous requirements concerning material properties and dimensional precision. The effect of different additives (borosilicate glass, alumina and zirconium silicate) on features of silica-based ceramic cores was investigated. The elaborated in this paper material for cores fabrication composed of 64.0 wt% quartz glass, 11.0 wt% borosilicate glass, 13.0 wt% zirconium silicate and 12.0 wt% alumina reveals mechanical strength equal to 25.8 MPa, coefficient of thermal expansion of 3.52 . 10 −6 1/K , surface roughness equal to 2.3 μm, shrinkage less than 1.9% and average pore size diameter of 4.8 μm. The thin-walled long ceramic cores were shaped by the high-pressure injection moulding method, which covered the choice of a thermoplasticizer, feedstock development and determination of the processing parameters protecting the formed cores from imperfection and deformation. The after-shaping process of cores manufacturing included water and thermal debinding, sintering and dimension measurement. The high dimension accuracy of cores was verified by measurement results made on the coordinate measurement machine.

Fabrication of silica-based ceramic cores with internal lattice structures by stereolithography

Ceramic cores are widely used in investment casting, and ideal properties of cores are essential for high-quality castings. Under the circumstances requiring thick cores, solid cores are likely to encounter deformation and cracking defects due to the accumulation of shrinkage. Therefore, with the superiority of ceramic stereolithography in producing complex ceramic parts, hollow cores with lattice structures were designed and fabricated. The dimensional accuracy and properties of the green and sintered bodies were evaluated. Results show the dimensional accuracy of sintered cores is controlled within ±0.25 mm benefited from the precise green bodies. The mechanical properties are not obviously deteriorated. The bending strength reaches 11.94 MPa at room temperature and 12.87 MPa at 1,500 °C with a creep deformation of 0.345 mm. Furthermore, casting verifications prove that the hollow cores meet the requirements of investment casting. Smooth casting surfaces are obtained, at the same time, the core-removal efficiency is improved by over 3 times.

Spectral Chebyshev method coupled with a high order continuation for nonlinear bending and buckling analysis of functionally graded sandwich beams

AbstractThe main objective of the present work is to couple the spectral Chebyshev differential quadrature method (SCDQM) to the high order continuation method (HOCM) which was proposed in previous works with several discretization techniques. This new approach (SCDQM‐HOCM) is proposed to analyze the nonlinear bending and buckling analysis of functionally graded sandwich beams. The originality of this work consists also to use a beam model which taken into account the nonlinear term neglected in several works of the literature. This term makes it possible to have the buckling and bending problems by using the classical Timoshenko model and to handle the boundary conditions that several works could not to take into account. A strong form of nonlinear equations is established based on the first order shear deformation theory of beams with the von‐Kármán kinematic hypothesis. Regarding functionally graded materials (FGM), two typical types are investigated: sandwich beam with FGM faces and ceramic core (Type‐A), and sandwich beam with FGM core and uniform faces (Type‐B). The accuracy and efficiency of the SCDQM‐HOCM compared with finite element method coupled with high order continuation method (FEM‐HOCM) are illustrated on numerical examples of the FGM beams and then the FG sandwich beams. Furthermore, a parametric study is led to carry out the influence of different skin‐core‐skin thickness ratios, span‐to‐height ratio, and volume fraction on the bending and buckling behavior of FG sandwich beams subjected to different loadings and various boundary conditions.

29. Imaging outcome at 24-month follow-up in a prospective, multicenter study of two-level cervical arthroplasty with a PEEK on ceramic artificial disc

<h3>BACKGROUND CONTEXT</h3> The use of cervical total disc replacement (cTDR) continues to increase. The implants continually evolve with respect to design and materials. Imaging studies of these devices provides insight to their ability to provide and maintain range of motion (ROM), disc height, and depending on the implant materials, facet joint assessment. <h3>PURPOSE</h3> The purpose of this study was to evaluate the imaging outcome of a PEEK-on-ceramic artificial disc for the treatment of two-level cervical disc disease. <h3>STUDY DESIGN/SETTING</h3> Data for this study came from a prospective, multicenter, non-randomized, historically controlled FDA Investigational Device Exemption (IDE) trial evaluating the Simplify®Cervical Artificial Disc for use at two levels. <h3>PATIENT SAMPLE</h3> Two-level cTDR was performed in 182 patients treated for symptomatic cervical disc degeneration with radiculopathy/myelopathy. <h3>OUTCOME MEASURES</h3> The primary outcome measures were ROM, disc height, and heterotopic ossification (HO) of the treated levels. MRI was used to assess the facet joints. <h3>METHODS</h3> The cTDR is composed of PEEK endplates with a mobile ceramic core. Radiographic evaluations were performed preoperatively, at hospital discharge, and 6 weeks, and 3, 6, 12, and 24 months postoperatively. MRI was performed pre- and 24 months postoperatively. All images were evaluated by an independent core lab. HO was evaluated based on a 0 (normal) to 4 (bridging bone) scale. Facets joints were scored on a 4-point scale ranging from 0 (normal) to 3 (severe degeneration) based on the MRI performed pre- and 24 months postoperatively. <h3>RESULTS</h3> At the superior cTDR level, the mean ROM improved from 8.0° prior to surgery to 9.5° at 24-month follow-up. At the inferior level, the values were 6.6° and 8.9°, respectively. At both operated levels, mean disc height increased postoperatively and the increase was maintained through 24-month follow-up. At the superior index level, the preoperative mean height was 3.1 mm and at 24 months it was 4.3 mm. At the inferior index level, the preoperative height was 3.1 mm and was 4.0 at 24 months. HO rates at 24-month follow-up were, the superior index level, severe HO (Grade 3) occurred in 8 patients (5%). Bridging HO (Grade 4) was also seen in 8 patients (5%). At the inferior index level, severe and bridging HO was seen in 17 (10%) and 5 (3%) patients, respectively. There was a lack of facet degeneration progression assessed on MRI between pre- and 24-month follow-up. No patient had severe facet degeneration at either operated level at either time point. The percentage of patients with a grade of moderate facet degeneration did not change at either level 8% at the superior index level and 5% at the inferior index level. At both levels, there appeared to be patients changing from the "none" category to the "mild" category. At the superior level prior to surgery, the figures for "none" and "mild" were 62% and 30% respectively. At 24-month follow-up, the figures were 52% and 39%, respectively. A similar pattern was seen at the inferior index level. <h3>CONCLUSIONS</h3> This study adds to the expanding evidence that two-level cTDR increases and maintains ROM and disc height and through 24-month follow-up. The majority of cTDR patients did not experience bridging HO. This PEEK-on-ceramic cTDR produces minimal artifact, allowing for reliable MRI visualization. This was used to evaluate the facet joints and a lack of facet degeneration progression was found. <h3>FDA DEVICE/DRUG STATUS</h3> Simplify Cervical Artificial Disc 2-level (Approved for this indication).

In-situ synthesis of high-performance Al2O3-based ceramic cores reinforced with core-shell structures

The complex structure of the ceramic cores is key to the preparation of an aero-engine hollow blade with excellent cooling performance. The traditional methods such as hot-press moulding are difficult to prepare complex-structured ceramic cores, and 3D printing technology provides a new idea for the preparation of complex-structured ceramic cores. Using SiO2 and Y2O3 as mineralizers in Al2O3-based ceramic cores, high-performance ceramic cores with a core-shell structure was successfully prepared by 3D printing. Additionally, the changes in microstructure and properties at different sintering temperatures were studied. The results showed that with an increase in the sintering temperature, a core-shell structure with Y2Si2O7 as the shell and Y2O3 as the core was formed, and the reinforced phases such as mullite were generated at the same time. The formation of core-shell particles suppressed the energy loss of cracks. The generation of the liquid phase led to the tight bonding of the Al2O3 particles. The synergistic effects of the core-shell structures and the reinforced phases enhanced the flexural strength. When the sintering temperature was 1380 °C, the comprehensive performance met the application requirements of the ceramic cores, and the flexural strength and porosity were 19.3 MPa (at 1500 °C) and 30.5%, respectively. The 3D-printed ceramic core by low-temperature sintering with a core-shell structure was successfully prepared, which promoted the wider application of DLP-3D printed ceramic cores technology in the field of precision casting. This is expected to reduce the energy consumption during the sintering process and promote the production of high-performance complex-structured ceramic cores.

Recent advances in the stereolithographic three-dimensional printing of ceramic cores: Challenges and prospects

The increasing demand for geometrically complex structures—specifically, higher-inlet-temperature turbine blades for the fifth-generation or other high-generation machines of advanced fighter aircrafts—has made the development of more complex double-walled three-layer hollow-cavity structures a necessity. However, this requires the preparation of complex ceramic cores and advanced, integrated technologies. Stereolithographic three-dimensional printing (SLA-3DP) technology, with digital control upon material morphology, composition, and structure, is a high integration and versatile technique that is superior to the traditional manufacturing techniques for ceramic cores, including gel casting, injection molding, and hot pressing. The latent capacity of this technique is contingent on the progress of processing routes that significantly reduce the distortion and defect formation in response to the elimination of the reacted organic monomer phase during photo-curing. Despite the tremendous progress in the field, multiple challenges remain, such as the preparation of high-solid-content and low-viscosity suspensions, SLA-3DP of large double-walled ceramic cores with complex structures, and process optimization and sinter strengthening for the fabrication of ceramic cores. These challenges have prevented the broader applications and reduced the impact of the SLA-3DP technology. This review discusses cutting-edge research on the crucial factors governing this production method. Specifically, we outline the existing challenges within the field and provide our perspective on the upcoming research work and progress.

Crack initiation and propagation in a high-solid-loading ceramic core fabricated through stereolithography 3D printing

Ceramic cores are applied in electronics, aerospace, medicine, military, automotive, and other fields. However, the effects of the build direction, along with the shrinkage of the green body and thermal stress, on the mechanical properties of 3D ceramic cores have not been elucidated. To reveal the optimum conditions for crack resistance in a high-solid-loading ceramic core, a silicon-based ceramic core with a solid content of 60 vol% was fabricated through stereolithography 3D printing and analyzed in terms of its microstructure-level crack initiation and propagation. The green bodies were initially 3D printed in different build directions (length-directed, width-directed, and height-directed) and then sintered at different temperatures (1100 °C-1250 °C). Higher sintering temperatures generally produced more cracks, and the synergistic effects of the sintering temperature and build direction induced crack initiation and propagation. The width-directed sample sintered at 1200 °C, in particular, exhibited effectively controlled crack growth without sacrificing strength.

3D printing of silica-based ceramic cores reinforced by alumina with controlled anisotropy

Ceramic core (CC) is a key component in the casting of aero-engine turbine blades, and CC through 3D printing is crucial to the growing aviation technology. However, these silica CCs are highly limited by their high temperature softening and inevitable anisotropy. In this work, silica-based CCs reinforced by alumina powders are manufactured by 3D printing via digital light processing (DLP) stereolithography, and the anisotropy in microstructure and property was investigated. In the CC without alumina powders, multilayer structures with significant interlayer gaps are exhibited in horizontal printing direction suggesting significant anisotropy in microstructure, which is related to the particle deposition in printing. As the alumina content is 6 wt%, microstructures become uniform, due to the enhanced particle rearrangement between different layers. To assess the mechanical anisotropy, the ratio of vertical strength to horizontal strength (σV/σH) is raised, and the σV/σH ratios rise from 0.45 to 0.86 at room temperature and 0.52–0.89 at 1540 °C with increasing alumina content from 0 to 6 wt%. As the alumina content is 6 wt%, the CC exhibits high temperature flexure strengths as high as 17.9 MPa and 19.5 MPa in different directions, well satisfying the demands for turbine blades casting. This article inspires a profound understanding on the anisotropy control in 3D printing of CC with excellent high-temperature mechanical properties.

Coating optimization of yield pseudoplastic paste-based stereolithography 3D printing of alumina ceramic core

Yield pseudoplastic paste is prepared for self-supported stereolithography (SLA) 3D printing with critical shear stress of 290.7 Pa and viscosity of 28810 mPa·s under strain rate of 30 s−1. Simulation analysis of paste coating is carried out based on established constitutive equation. Furthermore, corresponding stress field is analyzed under different layer thicknesses (25–100 μm) and blade speeds (1.5–4.5 mm/s). Then, flexural strength, porosity, surface roughness and microstructure of components, printed with different layer thicknesses and sintered at different temperatures, are systematically investigated. Finally, complex-shaped cores are fabricated with flexural strength of 38.56±1.45 MPa, porosity of 21.57±0.8% and surface roughness of Ra < 3 μm. The optimized parameters include layer thickness of 25–50 μm, blade speed of 3.5 mm/s, and sintering temperature of 1300 oC. Moreover, step-like undulating fracture morphology of the core is observed along printing layer, which shows that the coating process has an important influence on the mechanical properties of ceramic parts.

Microstructure and mechanical properties of 3D-printed nano-silica reinforced alumina cores

Ceramic cores are an important component in the preparation of hollow turbine blades for aero-engines. Compared with traditional hot injection technology, 3D printing technology overcomes the disadvantages of a long production cycle and the difficulty in producing highly complex ceramic cores. The ceramic cores of hollow turbine blades require a high bending strength at high temperatures, and nano-mineralizers greatly improve their strength. In this study, nano-silica-reinforced alumina-based ceramic cores were prepared, and the effects of nanopowder content on the microstructure and properties of the ceramic cores were investigated. Alumina-based ceramic cores contained with nano-silica were prepared using the vat photopolymerization 3D printing technique and sintered at 1500 °C. The results showed that the linear shrinkage of ceramic cores first increased and then decreased as the nano-silica powder content increased, and the bending strength showed the same trend. The fracture mode changed from intergranular to transgranular. The open porosity and bulk density fluctuated slightly. The weight loss rate was approximately 20%. When the nano-silica content was 3%, the bending strength reached a maximum of 46.2 MPa and 26.1 MPa at 25 °C and 1500 °C, respectively. The precipitation of the glass phase, change in the fracture mode of the material, pinning crack of nanoparticles, and reduction of fracture energy due to the interlocking of cracks, were the main reasons for material strengthening. The successful preparation of 3D printed nano-silica reinforced alumina-based ceramic cores is expected to promote the preparation of high-performance ceramic cores with complex structures of hollow turbine blades.

Enhanced 3D printed Al2O3 core via in-situ mullite

The ceramic core plays an important role in the preparation of aero-engine hollow blades, as it can directly determine the precision and pass rate of the cooling passage in the blade cavity. Sufficient high-temperature bending strength, high open porosity, and low sintering shrinkage are the main requirements for qualified ceramic cores. In order to prepare qualified ceramic cores with complex structures, in-situ mullite-reinforced Al 2 O 3 -based ceramic cores were successfully prepared using vat photopolymerization 3D printing technology. The in-situ synthesis of mullite was designed through thermodynamic analysis. The influence mechanisms of the sintering temperature and doping amount of fused silica on the open porosity, sintering shrinkage, and bending strength of the core were systematically investigated. With an increase in the sintering temperature and doping amount of fused silica, the porosity of the in situ mullite-reinforced ceramic core decreased. Sintering shrinkage increased with an increase in the sintering temperature and doping amount of fused silica. The cores containing 20 wt% fused silica showed the smallest sintering shrinkage. The bending strength increased with an increase in the sintering temperature and the doping amount of fused silica. A core doped with 20 wt% fused silica had the highest bending strength at 1773.15 K. Furthermore, 20 wt% fused silica doping, sintered at 1673.15 K, can be used to prepare in-situ mullite enhanced Al 2 O 3 -based cores with the best comprehensive properties. This core has a higher open porosity (40%), suitable bending strength of 25 MPa (at 1773.15 K), and lower sintering shrinkage in the Z direction. The significance of this study lies in the regulation of in-situ mullite generation and viscous flow in solid-liquid sintering by adjusting the doping amount of fused silica and the sintering process, and this opens up new pathways by the coordinated regulation of strength, open porosity, and sintering shrinkage of 3D printed ceramic cores. • An in situ mullite-enhanced ceramic core was successfully prepared using 3D printing technology. • In-situ mullite was synthesized through thermodynamic analysis in 3D printing ceramic cores. • Strength, porosity and sintering shrinkage of 3D printing ceramic cores were controlled. • A novel method for the coordinated regulation of strength, porosity and sintering shrinkage of 3D printing ceramic cores.

Improved mechanical properties of SiC fiber reinforced silica-based ceramic cores fabricated by stereolithography

• The SiC fiber reinforced silica-based ceramics were prepared via stereolithography. • Excellent high temperature mechanical properties were obtained by the reinforcement of SiC fibers. • SiC fiber can reduce the linear shrinkage of silica-based ceramics greatly through the oxidation reaction of SiC. • The manufacturing precision of ceramic parts is improved a lot. Silica-based ceramic cores have been widely used to fabricate aero-engine hollow blades due to their moderate high temperature mechanical properties and excellent leachability. In this study, silica-based ceramics with SiC fiber addition were prepared via stereolithography, and the influence of SiC fiber content on mechanical properties of the obtained silica-based ceramics was investigated. With the increase of SiC fiber content, linear shrinkage gradually decreased, while room temperature flexural strength and high temperature flexural strength first increased and then decreased. As SiC fiber content increased to 4.0 wt%, linear shrinkage was reduced to 0.62% resulting from the oxidation of SiC. Furthermore, room temperature flexural strength was improved from 11.79 MPa to 23.83 MPa and high temperature flexural strength was enhanced from 15.64 MPa to 34.62 MPa with 4.0 wt% SiC fiber addition due to the reinforcement of fibers and the enhanced β-cristobalite content, which meets the need of ceramic cores. Therefore, it demonstrates the capability of fabricating high-performance and high-precision silica-based ceramic cores reinforced by SiC fibers via stereolithography for rapid manufacturing of hollow blades.

Defect control in digital light processing of high-solid-loading ceramic core

In order to investigate the defect control mechanism and the optimal cure parameter window, high-solid-loading ceramic-core green-body samples were fabricated by digital light processing (DLP) with different cure parameters. The defects appearing on the sample surface were observed. The causes of the wrong-cured zone and the propagation mechanism of UV light in the ceramic suspension were explained. The effect of different cure parameters on the printed structure of single- and multi-layer samples was investigated. The results showed that the single-layer sample had excellent cure accuracy, and the step effect was significantly reduced in the multi-layer samples at the exposure energy density of 6–8 mW/cm2 and the exposure time of 2.5–3.5s. Based on the systematic observation of the sample structure, a system for prediction, evaluation, and process optimization of defects in ceramic-core green-body samples was proposed.

Hygro-thermo-mechanical stability analysis of variable thickness functionally graded sandwich porous plates resting on variable elastic foundations using finite element method

In this study, finite element formulation of various four-unknown shear deformation theories is presented for hygro-thermal-mechanical stability analysis of variable thickness functionally graded sandwich porous (FGSP) plates resting on variable elastic foundations. In engineering practice in general and the military sector in particular, smart structures are employed relatively regularly. Three novel porosity distribution principles, which include a fully ceramic core layer and two functionally graded material surface principles, may be widely applied in those fields. These include a fully ceramic core layer and two functionally graded material surface principles, where the plate thickness changes in two directions according to bi-linear, bi-parabolic, and bi-sinusoidal laws. A quadrilateral with four nodes, each with sixteen degrees of freedom, is developed using a C1 -order conforming Hermite function and the numerical integration technique is employed in the study of hygro-thermal-mechanical stability under any boundary conditions. The results of the proposed theory and model are compared with the results available in the literature to determine the reliability of the calculation program. A collection of factors affecting the mechanical behavior of variable thickness plates with hygro-thermal-mechanical stability is described. The numerical results reveal that the porosity distribution, the thermo-humidity environment, and the variable thickness elastic foundation all impact the hygro-thermal-mechanical stability responses of FGSP plates with variable thickness.

A zone-layered trimming method for ceramic core of aero-engine blade based on an advanced reconfigurable laser processing system

Ceramic structural parts are one of the most widely utilized structural parts in the industry. However, they usually contain defects following the pressing process, such as burrs. Therefore, additional trimming is usually required, despite the deformation challenges and difficulty in positioning. This paper proposes an ultrafast laser processing system for trimming complex ceramic structural parts. Opto-electromechanical cooperative control software is developed to control the laser processing system. The trimming problem of the ceramic cores used in aero engines is studied. The regional registration method is introduced based on the iterative closest point algorithm to register the path extracted from the computer-aided design model with the deformed ceramic core. A zonal and layering processing method for three-dimensional contours on complex surfaces is proposed to generate the working data of high-speed scanning galvanometer and the computer numerical control machine tool, respectively. The results show that the laser system and the method proposed in this paper are suitable for trimming complex non-datum parts such as ceramic cores. Compared with the results of manual trimming, the method proposed in this paper has higher accuracy, efficiency, and yield. The method mentioned above has been used in practical application with satisfactory results.

Art Decoration Design of Electrochemical Silicon Oxide Ceramic Sculpture Based on 3D Printing Technology

In order to solve the art decoration design of silicon oxide ceramic sculpture, a method for silicon oxide ceramic sculpture based on 3D printing technology is proposed. Firstly, the density of photosensitive resin premix before curing was measured by pycnometer method; the photosensitive resin was coated on tinplate and then put into a self-made UV curing box for curing. Secondly, the critical exposure and critical transmission depth of photosensitive resin without formula are calculated. Finally, the viscosity of ceramic slurry was measured by mixing S2 photosensitive resin formula with ceramic powder with different nano silica content. It is proved that the addition of nano silica powder can promote the decomposition of quartz glass and increase the sintering degree of the ceramic core. The primary sintering shrinkage of ceramic core gradually increases with the increase of nano silica content. In the length direction, the shrinkage increases from 3.33% to 5.61%; in the width direction, the shrinkage increases from 2.98% to 4.74%; and in the height direction, the shrinkage increases from 3.18% to 5.00%.