Optimal Parameters Research Articles

Optimization and Kinetic Study of Manganese Leaching from Pyrolusite Ore in Hydrochloric Acid Solutions with Oxalic Acid

The leaching behavior of pyrolusite minerals was examined in hydrochloric acid solutions, including oxalic acid, to evaluate the influence of various experimental conditions. The optimum parameters for the leaching process were found in the first stage, and the process's kinetics were assessed in the second. The concentrations of oxalic acid, hydrochloric acid, and temperature were chosen as independent variables in the optimization experiments, with the central composite design used to analyze the experimental data. The optimum concentrations for oxalic acid, hydrochloric acid, and temperature were determined to be 0.75 mol/L, 1.2 mol/L, and 60 °C, respectively. The leaching rate was determined to be 97.4% for 120 min of response time in optimum situations. The kinetic assessment experiments studied the effects of solid/liquid ratio, particle size, stirring speed, and temperature on the manganese leaching rate from pyrolusite. In the studies, the leaching rate was shown to rise with increasing temperature and stirring speed, as well as with decreasing particle size and solid/liquid ratio. The kinetic analysis revealed that the leaching kinetics matched the mixed kinetic model, and a mathematical model for the leaching process was developed. This process's activation energy was determined to be 29.05 kJ/mol.Graphical

Performance optimization of an air-assisted electrostatic spraying unit using response surface methodology

An air-assisted electrostatic spraying unit along with a set-up to measure the spray current was developed. Response surface methodology was used to optimize the performance of the developed electrostatic spraying unit. The optimum parameters such as electrode diameter, electrode voltage, electrode position and target distance for maximizing charge-to-mass ratio (CMR) were determined to be 30 mm, 2000 V, 0 mm and 400 mm, respectively Predicted CMR under optimal conditions was experimentally validated. Furthermore, charged spray demonstrated 1.5 to 4.6 times higher droplet deposition with lower uniformity coefficient (2.13–2.14) and relative span factor (0.84–0.9) compared to uncharged spray.

Study on Mechanical and Electrical Properties of High Content CNTs/Cu Composites.

It is expected that composites made of carbon nanotubes (CNT) and copper (Cu) display both mechanical and electrical properties, but the low damage dispersion and high-quality composite of high-content CNTs have always been research difficulties. In this paper, high-content CNTs/Cu composites were prepared. The effects of the sintering method, sintering temperature, directional rolling and the CNTs' content on the relative density, hardness and electrical conductivity of the composites were studied. The uniform dispersion of high-content CNTs in Cu matrix was achieved by ball milling, sintering and rolling, and the processes did not cause more damage to the CNTs. The properties of composites prepared by spark plasma sintering (SPS) and vacuum hot pressing sintering (HPS) were compared, and the optimum process parameters of SPS were determined. When the CNTs' content is 2 wt.%, the hardness is 134.9 HBW, which is still 2.3 times that of pure Cu, and the conductivity is the highest, reaching 78.4%IACS. This study provides an important reference for the high-quality preparation and performance evaluation of high-content CNTs/Cu composites.

Parametric study and optimization of H-type finned tube heat exchangers with honeycomb arrangement using Taguchi method

Enhancing the efficiency of flue gas waste heat utilization is an important way to achieve carbon peaking and carbon neutrality goals. In this paper, a three-dimensional numerical model of an H-type finned tube heat exchanger with honeycomb arrangement is developed. Firstly, the effects of five parameters are analyzed using the control variable method, including the oblique tube pitch, the ratio of fin height to oblique tube pitch, fin pitch, fin thickness and slit width. Then, the Taguchi method was used to investigate the interaction effects of the five geometric parameters. Numerical simulations of 27 cases with different parameter combinations were carried out and the heat transfer and flow friction characteristics and their overall performance were discussed in detail. The results show that oblique tube pitch has the most significant effect on heat transfer capacity, fin pitch has the most significant effect on overall performance, and slit width has the least effect on both. Finally, the optimum parameter combinations were obtained. When inlet velocity ranges from 5 m/s to 10 m/s, heat transfer performance is increased by 46.3 %-52.1 %, pressure drop is increased by 5.7 % − 11.3 %, and the overall performance PEC is improved by 63.5 %-105.9 %. The results of the study contribute to the development and optimization of new flue gas heat exchangers.

Ziziphus nummularia leaves extract mediated CuO nanostructures for photocatalytic degradation of Methylene Blue

In this study, Ziziphus nummularia leaves extract was applied for the synthesis of CuO nanostructures. The material was characterized by various techniques such as Infrared (IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray (EDX) and scanning electron microscope (SEM) analysis. The characteristic peaks in powder XRD pattern of nanostructured of CuO at 2θ of 32.33, 35.57, 38.71, 46.11, 48.80, 51.50, 58.22, 61.58, and 68.08◦, correspond to (110), (−111), (111), (−112), (−202), (112), (202), (−113), and (220), respectively, match with diffraction patter of standard monoclinic phase of CuO (JCPDS: 01–080-1916). Tauc plot was plotted and band gap energy was calculated, and found to be 2.4 eV. The material was tested as photocatalyst for degradation of MB, and worked well at optimum parameters such as dosage of catalyst 25 mg, concentration of MB 20.0 mg L−1, pH 7 and time 120 min. The proposed method worked very well on synthetic solutions with degradation efficiency (%) ≥ 83.51 and an RSD (%) of ≤ 4.0.

Evaluation of Printing Parameters on 3D Extrusion Printing of Pluronic Hydrogels and Machine Learning Guided Parameter Recommendation.

Bioprinting is an emerging technology for the construction of complex three-dimensional (3D) constructs used in various biomedical applications. One of the challenges in this field is the delicate manipulation of material properties and various disparate printing parameters to create structures with high fidelity. Understanding the effects of certain parameters and identifying optimal parameters for creating highly accurate structures are therefore a worthwhile subject to investigate. The objective of this study is to investigate high-impact print parameters on the printing printability and develop a preliminary machine learning model to optimize printing parameters. The results of this study will lead to an exploration of machine learning applications in bioprinting and to an improved understanding between 3D printing parameters and structural printability. Reported results include the effects of rheological property, nozzle gauge, nozzle temperature, path height, and ink composition on the printability of Pluronic F127. The developed Support Vector Machine model generated a process map to assist the selection of optimal printing parameters to yield high quality prints with high probability (>75%). Future work with more generalized machine learning models in bioprinting is also discussed in this article. The finding of this study provides a simple tool to improve printability of extrusion-based bioprinting with minimum experimentations.

Process Optimization for Biosurfactant Production by Bacillus aryabhattai SPS1001 using Taguchi Method.

This study employs Taguchi design of experiments (DOE) to optimize biosurfactant yield by analyzing the impact of various input parameters. Signal-to-noise ratio analysis was utilized for optimization, corroborated by ANOVA findings. Regression equations depicted response behaviour and are validated through a confirmation test. Taguchi methodology identified optimal conditions for maximum biosurfactant yield: agitation (180rpm), inoculum size (2%), beef extract (5g/L), diesel (20ml/L), peptone (5g/L), NaCl (7g/L), incubation time (4days), pH (7.9), and yeast extract (6g/L). This yielded an 8.33% increase to 1.53g/L, with initial optimum parameters projecting 1.41g/L. ANOVA ranked and quantified control factor contributions, revealing agitation's significant (31.41%) impact on yield. The study underscores the viability of Taguchi's optimal conditions for substantial yield improvement within specific ranges. The strong alignment between expected and experimental yields affirmed the reliability of developed models for optimal yield selection. This study underscores the power of statistical techniques like Taguchi DOE and ANOVA in systematically enhancing biosurfactant production by Bacillus aryabhattai SPS1001 and paves the way for future advancements in bioprocess optimization.

Effect of Y2O3 on high temperature thermal compression performance of Cu–10W composites and microstructure analysis

In this study, Cu–10W and 2 wt%Y2O3/Cu–10W composites were successfully prepared via mechanical ball milling and spark plasma sintering. Hot compression experiments on the two materials were carried out in the temperature range of 300°C-600 °C and in the strain rate range of 0.01 s−1–10 s−1. The hot deformation activation energy of the two materials was calculated and a constitutive equation was established. The optimum hot deformation process parameters were obtained according to a hot processing map. The effects of Y2O3 on the thermal deformation behavior of the Cu–10W composites and their microstructures were investigated, and the results showed that Y2O3 could enhance the stability of Cu–10W at high temperatures. The activation energies of thermal deformation of Cu–10W and 2 wt%Y2O3/Cu–10W were 159.56 kJ/mol and 129.85 kJ/mol, respectively. Moreover, Y2O3 improved the interfacial bonding strength of Cu and W in the Cu–10W material, effectively preventing the generation of microcracks and pores during the high-temperature compression process; Y2O3 provides more nucleation sites in the recrystallization process, which is favorable for the excitation of recrystallization. A low strain rate at high temperatures favors the occurrence of recrystallization, and the 2 wt%Y2O3/Cu–10W composites tend to exhibit discontinuous dynamic recrystallization (DDRX) under high-Z-value conditions and continuous dynamic recrystallization (CDRX) under low-Z-value conditions.

Comparative study of electrogas and shielded metal arc welding processes on steel A537 welded joints

In this research, the electro-gas welding process was compared with a shielded metal arc welding process for welding steel A573 from a mechanical properties point of view. Visual and radiographic inspections confirmed the soundness of weldments produced by electro-gas welding and shielded metal arc welding techniques. Various assessments were performed, including hardness, tensile strength, V-notch impact toughness, macrostructure, microstructure, and electrochemical tests. The mechanical properties of the two welding processes were closely matched, with an average tensile strength of 590 MPa for electro-gas welding and 585 MPa for shielded metal arc welding. Furthermore, the influence of welding variables, such as groove design and heat input, on the welded joints’ quality, mechanical properties, and electrochemical behavior was thoroughly examined. Dilution estimates, particularly for the electro-gas welding process, were around 35%, and a significant similarity was observed between the chemical composition determined through dilution calculations and that obtained from chemical analysis using an arc spark emission spectrometer. Notably, the electro-gas welding process demonstrated exceptional productivity, surpassing the shielded metal arc welding process by more than elevenfold. The optimum welding parameters for the electro-gas welding process were identified to achieve superior mechanical properties, low corrosion rates, and reduced consumption of the welding electrodes. This included adopting a single V type and groove angle of 30° instead of 60°, resulting in a 23% reduction in economic costs. Selecting an appropriate heat input within the range of 12 to 14 kJ/mm further contributed to enhancing overall welding efficiency.

Machinability of gas metal arc based 3D printed Al-Mg 5356 alloy using wire-EDM

Wire-Arc Additive Manufactured (WAAM) is relatively new method of metal 3D printing in which the raw material is heated by the gas metal arc and the molten metal pool is deposited layer-by-layer using a computer numerically controlled axis drive system. Since WAAM needs a finishing process for attaining the final dimensions of the components, there is a need to investigate the machinability aspects of WAAM fabricated materials. This work investigates the machinability of Al-Mg 5356 alloy test samples fabricated by WAAM process using wire-electric discharge machining (Wire-EDM). The test samples were subjected to Wire-EDM and the obtained material removal rate (MRR), kerf width (KW) and surface roughness (Ra) were investigated at different Wire-EDM process settings of voltage, current, pulse-on time (Ton), pulse-off time (Toff) and wire speed (Ws). Statistical analysis revealed that current had a significant influence on MRR. Ton had a strong influence on KW and Ra, whereas Toff exhibited a considerable impact on all these responses. Notably, Ws demonstrated a significant impact on Ra. However, voltage was found to have statistically negligible impact on all the machining responses. Microstructural investigations and compositional analysis were conducted providing valuable information on the cut surfaces. The results derived from the present investigation are useful for predicting the optimum process parameter settings for machining of WAAM-based 3D printed Al-Mg alloy in various manufacturing industries.

Reviewing the Optimal Conditions for Efficiently Harnessing the Phytotherapeutic Potential of the Invasive Carpobrotus edulis (L.) N.E. Br Plant Threatening Plant Diversity

Within the scope of this study, the study conducted by Pereira et al. on the examination of the plant species Carpobrotus edulis (L.) N.E.Br, known as Hottentot-fig, is examined. This plant poses a great threat to biodiversity in coastal areas with its invasive feature. Pereira and his colleagues aimed to reveal the phytotherapeutic potential of the Hottentot-fig plant to turn this crisis situation into an opportunity. By evaluating the bioactive components and antioxidant and anti-inflammatory properties of the plant, which vary depending on harvest time and location, the usability of this plant in the food and nutraceutical industries has been demonstrated. In the methodology and results of this valuable study conducted by Pereira et al., methods such as extraction and total phenolic content HPLC-DAD were compared with other literature studies in order to determine the optimum parameters. By comparing the results of the study on Hottentot-fig, the shortcomings and strengths of the study were determined. Within the scope of our study, it is stated that alternative methods should be taken into consideration in addition to the known methods used in the literature, the results of these methods should be examined, and efficient results can be obtained with different method strategies.

Advancing reinforcement of sustainable gypsum composites: High-performance design by reusing waste materials

This study tends to optimize and develop an innovative gypsum material by incorporating hybrid waste compounds. Using a Doehlert design, this work explores the effects of introducing paper (X1), polystyrene (X2), and polyester fibers (X3), as well as their interactions, on gypsum's thermophysical and mechanical behavior. Bulk density, thermal conductivity, flexural strength, compressive strength, and the fire resistance test were performed on the developed formulations. Statistical analysis emphasizes the significant influence of all process variables on gypsum properties. Polyester fibers notably enhance flexural strength when combined with the cooperative effect of paper and polystyrene wastes, which strike a balance between physical and mechanical characteristics. The optimum formulation parameters lead to a significant 33% decrease in bulk density, a 43% reduction in thermal conductivity, a notable 42% increase in flexural strength, and a significant reduction in compressive strength of around 50%, but still meet the 2 MPa standard. The new samples show ductile behavior, highlighting gypsum's potential as a load-bearing material with excellent thermal insulation properties and impressive fire resistance. This research significantly improves our understanding of the effectiveness of a gypsum compound incorporating waste in a hybrid manner, bringing this approach into line with sustainable development objectives.

Green synthesis of CuO nanoparticles via Tulsi (Ocimum Sanctum) leaf extract for efficient adsorptive removal of doxycycline hydrochloride from aqueous solution

Due to significant consumption and improper disposal, the increase in emerging broad-spectrum antibacterial pharmaceutical contaminants in water bodies leds to degradation of quality of water resources and aquatic life, causes water availability issues. Doxycycline hydrochloride belongs to the tetracycline antibiotic class of drug, exhibits a significant persistence of toxicity in the aquatic environment. In the present study, eco-friendly CuO nanoparticles were biosynthesized using ocimum sanctum leaf waste extract and an investigation was carried out for the efficient adsorptive removal of doxycycline hydrochloride from pharmaceutical waste with harmful impacts on the environment. UV–visible spectra, XRD, FTIR, EDX, BET, HRTEM and FESEM analysis were used to characterize surface modification of the biosynthesized nanoparticles. Drug concentration, contact time, pH, temperature and adsorbent dosage were among the main adsorption parameters that were examined in order to optimize the most effective removal results. Maximum adsorption capacity of 8.56 mg/g was achieved at optimum process parameter; 100 mg/L, 170 min., pH 6 at 298 K. Moreover, various isotherm models were examined in order to accurately describe the adsorption equilibrium experimental results. Although, the thermodynamic data and kinetic study showed that the sorption process was spontaneous and endothermic, followed second order kinetic model. The outcomes showed that green synthesized CuO nanoadsorbent can be effectively employed for the removal of antibiotic medications from actual wastewater.

3D-Printed Meat Paste Using Minimal Additive: Assessment of Rheological and Printing Behavior with Post-Processing Stability

Printing foods in the desired shape with minimal additives and their stability after printing are the most important points for 3D food technology. In this study, the effects of water (5%, 10%, 15%, and 20%) and salt (0.5%, 1%, 1.5%, and 2%) on the printability of meat paste were evaluated to achieve improved textural and rheological properties. The printing parameters were examined at every stage, starting from the line thickness of the printed product, until the final 3D printed product was obtained. Accordingly, meat printability determined using different ingredient flow speed (3, 3.5, 4, 4.5, and 5), fill factor (1.2%, 1.3%, 1.4%, 1.5%, and 1.6%) and distance between layers (1.2, 1.4, and 1.6 mm). Salt addition increased the firmness and consistency of the samples, while the viscosity, storage modulus, and loss modulus decreased with the addition of water. Considering the line thickness and outer length, the most appropriate shape was obtained with 10% water and 1.5% salt. The optimal ingredient flow speed, fill factor, and distance between layers at a constant printing speed (2500 mm/min) were 3, 1.2%, and 1.4 mm, respectively. Four-layer-infilled 3D-printed samples maintained their initial shape after cooking, regardless of the cooking method. However, only baked products maintained their initial shapes among full-infilled samples. Although water and salt have different functions in meat, the use of the appropriate ratio is necessary for 3D-printed meat-based products to provide printability and post-production stability. To sum up optimum parameters and road map for printing meat and meat products including leftover meats and low-value by-products were revealed.

Experimental investigation on magnetorheological shear thickening polishing characteristics for SiC substrate

Silicon carbide (SiC) substrates are widely used in semiconductor and photoelectric applications due to excellent electrical and chemical properties. However, due to its inherent hard-brittle properties and chemical inertness, traditional polishing processes are facing great challenges to obtain excellent surface and subsurface quality for the SiC substrates. In this work, a novel polishing process i.e. magnetorheological shear thickening polishing (MRSTP) was proposed to explore the feasibility for the polishing of the SiC substrates. The MRSTP experiments were conducted using multiple magnetic-pole-coupled tools. The magnetic field characteristics of the polishing area were investigated via finite element simulation and actual measurements. The magnetic-pole-coupled tool was capable of generating high magnetic induction strength in the polishing area. The MRSTP medium was designed and prepared. The media were formed magnetic brushes by the excited magnetic field. The MRSTP experiments were conducted to investigate the effects of processing parameters on the polished surface roughness. The optimum process parameters were determined as the spindle rotational speed of 700 rpm, the feed rate of 600 mm/min, the work gap of 0.5 mm and MRSTP media CIPs particle size of 100 μm. The surface roughness of the workpieces was improved from initial 1.414 μm to 27.6 nm. It is verified that the MRSTP is the feasible ultraprecision polishing process for the SiC substrates.

Analysis and optimization of machining parameters of AZ91 alloy nanocomposite with the Influences of nano ZrO2 through vacuum diecast process

The magnesium alloy composite is a vital material for automotive applications due to its features like high stiffness, superior damping resistance, high strength, and lightweight. Here, the motto of research is to establish the AZ91 alloy nanocomposite with the exposures of 0, 1, 3, and 5 volume percentages (vol%) of nano zirconium dioxide (ZrO2) particles (50nm) through fluid stir metallurgy route associated with 1x105 Pa vacuum die cast process. Exposures on structural morphology, hardness, and impact toughness of composite are analyzed and identified as the nano AZ91 alloy composite enclosed with 5vol% is homogenous particle dispersion, enhanced hardness (97.6HV), and optimum toughness of 21.2J/mm2. However, composite faces machining difficulties due to the hard abrasive particles with higher hardness, resulting in tool wear. This experiment predicts the optimum mill parameters during the end mill operation of magnesium alloy nanocomposite (AZ91/5vol%) by using a tungsten carbide coated end mill cutter to attain the maximum metal removal rate with low surface roughness and tool wear analyzed via the general linear model (GLM) ANOVA approach. The input conditions for end milling operation vary, like feed rate (0.1 -0.4mm/rev), depth of cut (0.05 -0.2mm), and spindle speed (250-1000rpm). During the ANOVA GLM approach, the L16 design experiment is fixed for further interaction analysis. The results predicted by the depth to cut and feed rate were dominant and played a major role in deciding the tool wear, surface roughness, and MRR.

Rheological modelling of carbonyl-iron particles (CIP) paraffin oil-based magneto-rheological fluids

New types of magneto-rheological fluids are increasingly being developed lately, but there is a dearth of information on the performance of commonly used rheological models for emerging MRFs such as carbonyl-iron particles (CIP) paraffin-oil-based MRF. This work aims to investigate the performance of some rheological models for application in predicting shear stress and yield strength in an emerging MRF suitable for flow-mode applications. CIP, low viscosity paraffin oil, and lithium grease were used as magnetic particles, carrier fluid, and additives, respectively, to prepare the MRF. Based on different mixing proportions determined with the Taguchi method of experimental design, sixteen samples were prepared following a standard procedure. For each sample, the values of viscosity and shear stress were determined using a viscometer and rheometer, respectively, with an incorporated self-developed magnetic device. By fitting the data and using the multi-objective nonlinear programming solver in Micro-soft Excel to determine optimum parameters for each model, the Bingham Model, Herschel–Buckley Model, Casson Model, Cross models, and Power-law were used to model the experimental data. Predicted shear stress values and yield strength were then analyzed using ANOVA at a 5% confidence level. The relative errors were determined using RMSE, Mean Square Error, and Mean Absolute Error. There was a significant variation in the predicted outcomes of all the models. Overall, all the models gave relatively acceptable results. However, the Herschel-Buckley model gave the best results, while the Casson model gave the worst results, judging by their values of errors. It is shown that the Herschel-Buckley model should be best used for predicting the rheological characteristics of CIP and paraffin oil-based MRF.

Optimum Solar Cell Power Conversion Efficiency-Based Patterned Planar Solar Surface Morphology with Various Solar Cell Absorber Structures

This paper simulated the optimum solar cell power conversion efficiency-based planar solar surface morphology with various solar cell absorber structures. The spectral light intensity, reflected, absorbed, and transmission coefficients versus wavelength band spectrum varied from 300[Formula: see text]nm to 1300[Formula: see text]nm through the visible to near-infrared regions. The optimum solar cell performance parameters or key parameters are studied with different solar cell structure designs based on different surface contact and back contact layers. Cumulative generation current, cumulative electron–hole pair generation rate and electron–hole pair generation rate are clarified versus substrate depth for various solar cell structure designs. The absorbed current in substrate is optimized for various solar cell structure designs. Maximum power voltage and current are also optimized for the proposed solar cell structure design. The effective solar cell power efficiency is also demonstrated based on the optimized maximum power current and maximum power voltage.

Highly-efficient peroxymonosulfate activation by porous nano-MgO for tetracycline degradation: Surface hydroxyl groups and oxygen vacancies synergetic mediated nonradical process

Heterogeneous transition metal activation of peroxymonosulfate (PMS)-based advanced oxidation processes is limited by low cycling efficiency, secondary contamination, and high toxicity. In this study, a non-transition metal porous nano-MgO catalyst from natural dolomite was synthesized and PMS activation was performed to degrade tetracycline (TC). The nano-MgO/PMS system could achieve TC degradation of 88.09 % within 20 min under the optimum parameters (nano-MgO dosage of 0.2 g·L−1, PMS concentration of 0.3 mM), exceeding the efficiency of the PMS-alone system (11.66 %) by 7-fold, which was related to large specific surface area (41.19 m2·g−1) and defect structure of porous nano-MgO catalysts. As revealed by the quenching tests and electron paramagnetic resonance (EPR) analysis, different from transition metal activation PMS where radicals are generated, singlet oxygen (1O2) was essential in the nano-MgO/PMS oxidation process. Notably, the density functional theory (DFT) calculations demonstrated that nano-MgO with surface hydroxyl groups and oxygen vacancies exhibited the longer O-O bond length (1.47 Å), stronger adsorption energy of PMS (-4.07 eV), and faster electron transfer (0.91 e) than the only nano-MgO with surface hydroxyl groups, proving the surface hydroxyl groups and oxygen vacancies active sites in nano-MgO could synergistically mediate the PMS activation process. Furthermore, the proposed three TC degradation pathways and the toxicity evaluation of intermediates suggested that nano-MgO/PMS system have good ecological safety. This work offers an innovative approach for the cost-effective preparation of porous magnesium oxide with highly efficiency, offering a new perspective for understanding the PMS activation mechanism induced by non-transition metal.

Layup design and mechanical properties of an optimal dome profile

AbstractThe development of lightweight and high‐performance composite pressure vessels have become a popular research objective. The purpose of this study is to the layup design and improve the mechanical properties of pressure vessel structure with optimal dome profile under an internal pressure of 70 MPa. First, the prediction equations of fiber thickness for the cylindrical and dome sections are provided. Second, the influence laws of linear parameters on fiber layer thickness distribution are analyzed. Third, the optimal dome profile is used as the pressure vessel structure for the layup design, and the variable polar hole process is applied to solve the fiber thickness accumulation problem near the polar holes. Finally, the composite pressure vessel is modeled using Abaqus finite element software, and the stress and strain distributions of the liner and the composite layer under different internal pressure loads are analyzed under self‐tightening pressure. Results show that the variable polar hole process reduces the maximum thickness value by nearly 50.16% at the maximum fiber thickness of the dome. Under working pressure, the maximum stress of the liner is reduced by 43.41% after applying self‐tightening pressure. In addition, the variable polar hole process can effectively realize the lightweighting of composite pressure vessels while self‐tightening pressure can effectively improve the mechanical properties of the liner. This research provides a valuable reference for the design of composite pressure vessels.Highlights Fiber accumulation occurs in two bandwidth regions near the polar hole. The variable polar hole process can solve the fiber accumulation problem. The optimum dome profile geometric parameters are m = 0.8 and rc = 0.4R. The self‐tightening pressure improves liner loading capacity.