Outer Diameter Research Articles

Seepage rate and uniformity of the stalk composite pipe for subsurface irrigation

AbstractAn orthogonal experiment with three factors and three levels was conducted to study the seepage rate and uniformity of stalk composite pipe (SCP) under subsurface SCP irrigation (SSI). Furthermore, to determine the best application mode for SSI, the pipeline length, irrigation volume and inner–outer diameter of the SCP were considered at a 0.4 m working pressure. The three levels corresponding to each factor were 20, 40 and 60 m; 30, 45 and 60 L m⁻¹; and 28–60, 40–80 and 50–100 mm, respectively. The results indicated that the seepage rate gradually decreased with increasing pipeline length. The pattern of the change in the seepage rate with irrigation volume was not obvious. There was a positive correlation between the seepage rate and the inner–outer diameter of the SCP. The irrigation uniformity coefficient, which was calculated based on the width of the surface wetting front, gradually decreased with increasing pipeline length. The impact patterns of irrigation volume and inner–outer diameter on irrigation uniformity were ambiguous. The seepage rate reached its maximum at the pipeline length, irrigation volume and inner–outer diameter, which were 20 m, 30 L m⁻¹ and 50–100 mm, respectively. There was the highest irrigation uniformity, with a pipeline length, irrigation volume and inner–outer diameter of the SCP of 20 m, 60 L m⁻¹ and 40–80 mm, respectively.

Effects of adding micro/nano-scale surface roughness on upward flow boiling of R-134a through annular tubes

The enhancement of heat transfer efficiency is crucial for development of high-performance thermal systems in various industrial applications. This study investigates heat transfer and pressure drop during upward saturated flow boiling of R-134a in annular tubes featuring smooth and micro/nano-scale roughened copper surfaces achieved through sandblasting and chemical etching. A high-pressure chamber with a glass side is designed to observe surface wettability and measure contact angles of R-134a on both surfaces. The annular tubes, with inner and outer diameters of 28.6 and 42 mm respectively, and a total heated length of 1000 mm, undergo varying mass flux, vapor quality, and saturation pressure within ranges of 6.73–20.19 kg m−2 s−1, 0.14–0.95, and 530–1000 kPa, alongside heat flux variations from 608 to 2432 W m−2. Results indicate that the application of micro/nano-scale roughness to copper surfaces minimally reduces the contact angle of R-134a which slightly improves its wettability. However, this modification significantly increases the heat transfer coefficient by 256 % compared to the smooth tube, albeit with an associated increase in pressure drop. Additionally, increasing mass flux and vapor quality increases both the heat transfer coefficient and pressure drop. Furthermore, higher heat flux results in a higher heat transfer coefficient with a small increase in pressure drop. Also, the experimental results are compared with some of the available correlations in the literature. The novelty and significance of this work advances our understanding of effect of surface roughness on flow boiling characteristics. Understanding these phenomena is crucial for optimizing the design and performance of heat exchangers and other thermal systems used in various industries, including refrigeration, air conditioning, and power generation.

Retromolar intubation for the general anesthesia of maxillofacial fracture patients

BackgroundEvaluate the possibility of retromolar intubation for general anesthesia in patients with maxillofacial fractures.MethodsThe medical records of 54 patients with maxillofacial fractures who visited the Oral and Maxillofacial Surgery Department of Nantong First People’s Hospital from January 2020 to August 2022 were collected. The retromolar areas of each patient were measured from the coronal CT images, and correlated with the patient’s age, sex, type of fracture (i.e., maxillary fracture, mandibular fracture, or complex fracture of multiple maxillofacial bones), and the presence of the third molar (verified from 3D CT). The dimensions of the retromolar areas were finally compared with the outer diameter (OD) of standard endotracheal tubes (ETTs), most importantly the size 7.5 ETT (OD 10.3 mm) for male and the size 7.0 ETT (OD 9.8 mm) for female.ResultsThe survey included 38 male and 16 female patients, with an average age of 44.1 and 54.3 years, respectively. The dimensions of the retromolar area (height × width) were as follows: male, (9.39 ± 1.77) mm × (12.08 ± 0.98) mm on the left and (9.81 ± 2.23) mm × (11.77 ± 1.08) mm on the right; female, (8.82 ± 1.53) mm × (10.51 ± 1.00) mm on the left and (9.73 ± 1.60) mm × (10.63 ± 1.58) mm on the right. The width was always larger than the OD of the routinely used ETT, but the height could be smaller by less than 1 mm. However, the oral mucosa can be compressed to allow the ETT to fit in the retromolar area.ConclusionsThe retromolar area provided appropriate space to place a reinforced ETT for patients with maxillofacial fractures needing general anesthesia that must not interfere with intermaxillary ligation. Retromolar intubation can help maxillofacial fracture surgeries that focus on occlusal restoration.

The piezoelectric properties of three-phase electrospun PVDF/PZT/Multiwalled Carbone Nanotube composites for energy harvesting applications

In this study, the piezoelectric nanogenerators (PENs) based on the PVDF (polyvinylidene fluoride)/PZT (lead zirconate titanate, the particle size of <1 µm) incorporated with MWCNT (Multiwalled Carbone Nanotube, Outer diameter: 10 nm, Inner diameter: 4.5 nm, and Length: 3–6 µm) were produced using the electrospinning method. An β-phase content of 96.56 % in PVDF electrospun composites was arrived at due to the synergistic effect of the PZT ceramics and the MWCNT nanoparticles. The experimental results showed that a PVDF/PZT/0.7 wt%MWCNT composite with a thickness of 145 μm based on the PEN had an electrical power efficiency (0.16 μW) approximately 1.3 times higher at a vibrational frequency of 20 Hz under a resistive load of 46 KΩ as compared to that of the PEN based on the PVDF/PZT composite (0.12 μW). The PVDF/PZT/MWCNT-based PENs have promising potential for flexible energy transmission and structural health monitoring.

Quasi-CJ rotating detonation with partially premixed methane-oxygen injection: Numerical simulation and experimental validation

The efficiency gain of rotating detonation depends on several loss factors related to the chamber geometry, the injection principle, the propellants and their mass flow rates, and the equivalence ratio. Numerical simulation can help quantify these losses, and this work presents a Large Eddy Simulation (LES) of rotating detonation in an annular chamber and its validation against experiments. The simulation captured the mixing processes, the overall dynamics of the detonation, the deflagration, and the burnt gas expansion. The injection device was numerically designed to ensure partial premixing of the propellants before injection into the chamber. The chamber had a length of 110 mm, an outer diameter of 80 mm, and a radial width of 10 mm. The mixture consisted of gaseous CH4 and O2 with an equivalence ratio of 1.2 and a mass flow rate of 160 g/s. Combustion kinetics was modeled using a skeletal mechanism with 62 reactions and 16 species. The boundary conditions were adiabatic slip walls. The results reproduce well the detonation velocity (within 1% deviation) and the pressure variation behind the wave. The simulated OH* chemiluminescence compares well with experimental high-speed imaging of the outlet and side of the chamber. The simulation results indicate that 65% of the propellant mass is well mixed in front of the wave whereas 15% of the mixture is burned by deflagration. They show that CH4 and O2 do not axially stratify because they have similar injection dynamics between periodic perturbations induced by the rotating detonation. Good propellant mixing and low deflagration losses explain the high experimental detonation velocity, about 90% of DCJ, and a high combustion efficiency of 98%. These agreements between the computational and experimental results indicate that the simulation is capable of capturing the physical scales relevant to RDC operation and producing reliable results for RDC design.

Development of an Esophageal Sleeve With Variable Stiffness and Internal Diameter for Endoscopic Surgery

Abstract In natural orifice transluminal endoscopic surgery (NOTES), the flexible endoscopic surgical robot utilizes a continuum configuration to navigate narrow, multicurvature esophageal pathways. However, the tool channel's dimensional limitations and the restricted internal layout make it challenging to reduce the outside diameter and highly efficient variable stiffness function significantly. As a result, safe insertion into the esophagus and precise operation remains hugely challenging. In this paper, an esophageal sleeve with variable stiffness and internal diameter is developed for endoscopic procedures. The proposed esophageal sleeve adopts specially designed spiral elastic deployable parts that allow for variations in internal diameter. Furthermore, the elastic deployable parts are designed with serrated protrusion structures that can realize rapid transition between rigidity and flexibility under negative pressure. Fundamental experimental results showed that the outer diameter of the proposed esophageal sleeve can expand from 17 mm to 20 mm, providing inner access up to 13 mm for endoscopic instruments. The serrated protrusion structure allows the esophageal sleeve to rapidly transition from a flexible to a rigid state, resulting in a stiffness gain of approximately 5. Phantom experiments validated the effectiveness and usability of the proposed esophageal sleeve in assisting endoscope insertion, demonstrating its potential clinical value in endoscopic procedures. The significance of this study is the development of a device that can better assist endoscopic procedures.

Hip and pelvic geometry as predictors of knee osteoarthritis severity.

Malalignment is one of the most critical risk factors for knee osteoarthritis (KOA). Biomechanical factors such as knee varus or valgus, hip-knee-ankle angle, and femoral anteversion affect KOA severity. In this study, we aimed to investigate KOA severity predictive factors based on hip and pelvic radiographic geometry. In this cross-sectional study, 125 patients with idiopathic KOA were enrolled. Two investigators evaluated the knee and pelvic radiographs of 125 patients, and 16 radiological parameters were measured separately. KOA severity was categorized based on the medial tibiofemoral joint space widths (JSW). Based on JSW measurements, 16% (n = 40), 8.8% (n = 22), 16.4% (n = 41), and 56.8% (n = 147) were defined as grades 0, 1, 2, 3, respectively. There were significant differences between the JSW groups with respect to hip axis length, femoral neck-axis length, acetabular width, neck shaft angle (NSA), outer pelvic diameter, midpelvis-caput distance, acetabular-acetabular distance, and femoral head to femoral head length (P < .05). Two different functions were obtained using machine learning classification and logistic regression, and the accuracy of predicting was 74.4% by using 1 and 89.6% by using both functions. Our findings revealed that some hip and pelvic geometry measurements could affect the severity of KOA. Furthermore, logistic functions using predictive factors of hip and pelvic geometry can predict the severity of KOA with acceptable accuracy, and it could be used in clinical decisions.

Development of Certified Reference Materials Set for Open Porosity of Mammoth Ivory

Mammoth ivory is in demand in the jewelry industry, folk crafts and in the manufacture of cosmetics. This unique natural resource is an alternative to the prohibited extraction of ivory. It is fundamentally important for consumers to identify the raw material unambiguously as mammoth ivory and to accurately determine the grade of the material.The article presents the results of a study, which resulted in the development of a reference materials set of open porosity of the mammoth ivory. The reference materials are cylinders with an outer diameter of 30 mm and a height of 30 mm. Certified values of open porosity were determined by gas pycnometry. Reference materials are intended for certification of measurement methods and control of the accuracy of measurement results of open porosity of mammoth ivory in laboratory conditions. Reference materials can be used for various types of metrological control if the metrological characteristics of reference materials correspond to the established requirements.The research materials are of an applied nature for a number of economic sectors where mammoth ivory is used as a raw material. Reference materials of mammoth ivory are in demand in materials science, biology, geology, and other natural sciences, and in expert activities to determine the authenticity of products made from mammoth ivory. The article may also be of interest to students and teachers of natural sciences in higher education, as well as anyone interested in artifacts of ancient fauna.

Field stability of an Alvarez-type drift tube linear accelerator with small drift tubes

This study presents theoretical, simulation and experimental investigations of the field stability of a 7 MeV Alvarez-type drift tube linear accelerator (DTL) with small drift tubes (DTs). Although technical advances in permanent magnet quadrupoles make smaller DTs possible, resulting in higher shunt impedance, it is widely recognized that the DT-to-wall spacing must lie between ∼0.90 and ∼1.03 times a quarter wavelength (λ/4) to achieve field stability through post couplers (PCs). To enhance the shunt impedance of a DTL cavity, we decrease the outer diameter of the DTs and increase the inner diameter of the cavity, resulting in a DT-to-wall spacing of 1.16 times λ/4. A low-power experiment confirms that when the global tilt sensitivity slope is zero, the PC-to-DT distance is larger and there exists a stronger coupling between the PCs, resulting in a disturbed distribution of PC modes, where the frequencies of lower-order modes are overwhelmed by higher-order modes. The observed result is consistent with the analysis result given by the equivalent circuit theory and three-dimensional simulation. After field tuning by the trial-and-error method, the relative error of the axial electric field is within ±1.9% and the tilt sensitivity is within ±70%/MHz.

A Closed Loop Automated Drip Irrigation System Based on Arduino Uno

In recent years, the limited availability of irrigation water has made the optimal use of water a necessity. Successful irrigation practices in agriculture reduce excessive water usage and increase water use efficiency. Economical use of water can be made possible through modern irrigation systems. Nowadays, automatic control systems in agriculture have made significant progress and offer important advantages. In this study, a mini evaporation pan consisting of nested two cylinders was used (outer cylinder diameter 32 cm, inner cylinder diameter 27 cm, and both with a height of 20 cm) and the water remained at a constant level in both cylinders due to the notch beneath the inner cylinder. A water level sensor was placed inside the inner cylinder, and irrigation was activated based on the signal received from the sensor. The data from the sensor was processed by the microcontroller on the Arduino Uno, and three different irrigation applications were implemented by activating pumps connected to relays at 07:00, 14:00, and 21:00 o’clock, and then the mini-evaporation pan was refilled, and the system waited for the next irrigation period. The automation drip irrigation system maintained irrigation as a closed loop throughout the entire growth period of the lettuce plants using this approach. The addition of a fertilization unit to this system could make it more effective in plant production. The performance of the system will be significantly enhanced by enabling hardware that provides irrigation and fertilization to the plant according to its specific needs in terms of timing and quantity, along with appropriate software integration.

Numerical investigation on effects of plain, perforated, and dimpled twisted tape inserts in a tube to flow and heat transfer characteristics

This research delves into improving heat transfer within tube by incorporating twisted tape inserts numerically comprising seven cases: basic twisted tape, perforated twisted tape with lengths of 25, 50, and 100mm, dimpled twisted tape with lengths of 25, 50, and 100mm. Analyses have been conducted at five different Reynolds numbers (10,000, 12,000, 15,000, 18,000, 20,000) using water as the working fluid. Physical dimensions of the geometry include tube length of 1000mm, inner diameter of 17mm, and outer diameter of 21mm. The twisted tape is also 1000mm long, with width of 17mm and thickness of 1mm. Results are compared to smooth tube in terms of Nusselt number and friction factor. Best improvement was obtained for 25mm dimpled twisted tape with 42%, while improvement for perforated tape was 28.7% and for plain tape 24%. Higher friction factors were obtained at 25mm dimpled tape making these configurations useful for industry despite pressure drop.

Aspects Regarding the Physical Parameters and Wear in the Work Process of the Disc Openers for Seeding Machines

This paper primarily presents statistics on the variation of physical characteristics (dimensions and mass) for the coulter discs of double-disc seeders. This statistic was calculated based on actual measurements of the probability density and cumulative probability for the mass of the discs, their average thickness, and outer diameter. These parameters (m = 4000 g, g = 4 mm, D = 380 mm) are tracked from the design phase to the actual realization phase, being the parameters specified in the purchase phase by users from agricultural machinery distributors. The standard deviation and deviation from the mean for a cumulative normal (Gaussian) distribution were calculated, and an analysis was made for the decrease of the mentioned parameters in discs already used for sowing cereals on an area of 80 hectares, due to the wear that appeared as a trace of the contact with the soil and the abrasive wear caused by it. Testing of disk parameters using both logarithmic and Gaussian distributions was performed, and test results are presented through appropriate graphs. With small deviations (which appeared for known or unknown reasons), it can be stated that the distribution of the mentioned parameters is generally a normal-type distribution. If the new discs are 15″ in diameter, experts recommend that they be replaced when they reach a diameter of less than 14.5 inches. This study can provide a reference for improving the physical characteristics of opener discs of seed drills in no-till conditions and beyond.

Storage Life of Particle-Filled Polymer Composites Considering Aging Effects.

This study investigates the storage life of particle-filled polymer composites (PFPCs) under the influence of aging effects. High-temperature accelerated aging tests were conducted at 60 °C, 70 °C, and 80 °C for various days to analyze the impact of aging time and temperature on the mechanical behavior of the materials. A predictive model for crosslink density was established using the Arrhenius equation, and the relationship between crosslink density and relaxation modulus was determined based on polymer physics theory. On this basis, a viscoelastic constitutive model that incorporates aging effects was developed. Structural analyses of a PFPC column with a length of 2.3 m and outer diameter of 1.8 m were performed using the UMAT subroutine in ABAQUS. Subsequently, a safety margin assessment method based on dewetting strain was employed to predict the storage life of the PFPC column. The results indicate that the aging viscoelastic constitutive model effectively characterizes the hardening effects caused by aging in the composites during storage. The storage life for the PFPC column considering aging effects decreases from 22 years to 19 years compared to models that ignore such effects. This approach provides a reference for estimating the storage life of PFPC columns considering aging effects.

Shape Sensing of Resin Pipe with a Helical-winding Optical Fiber in Bending Test

In this study, we developed a shape-sensing technique for a pipe. An optical fiber was helically bonded on the outer surface of a resin pipe whose length, outer diameter and inner diameter are 3200 mm, 34 mm, and 26.6 mm, respectively. Firstly, four grooves were made on the surface along the pipe in a helical pattern with the same pitch of 360 mm. At the one pipe end, adjacent grooves were offset by 90 degrees and the offset was maintained along the pipe. The single-mode fiber was put into a groove and fixed by epoxy and then it was embedded into the adjacent groove. Consequently, the optical fiber was going back and forth twice along the pipe. At the pipe ends, there were stress-free fibers between the grooves. Shape sensing for the pipe is conducted as follows. 1. Strain distributions along the grooves are measured by a distributed fiber-optic strain sensing system. 2. The bending strain is extracted from the measured strain to calculate the curvature and bending angle. 3. The shape of the pipe is reconstructed based on the curvature and bending angle using the Frenet-Serret formulas. Three-point bending tests were conducted. In the tests, the pipe ends were clamped to be the fixed ends and a point load was applied to the pipe center. Strain distributions were measured by tunable wavelength coherent optical time domain reflectometry (TW-COTDR) or optical frequency domain reflectometry (OFDR). Then the pipe shape was reconstructed as described above. We compared the reconstructed shape with the deformation calculated by finite element analysis and the agreement was excellent. If we insert the developed pipe into a bedrock and reconstruct the pipe shape continuously, it is expected that we can detect cracks or damage in the bedrock. This approach is expected to make rock excavation constructions safer.

TiO2 nanotubes with customized diameters for local drug delivery systems

AbstractIn this study, we evaluated the drug release behavior of diameter customized TiO2 nanotube layers fabricated by anodization with various applied voltage sequences: conventional constant applied potentials of 20 V (45 nm) and 60 V (80 nm), a 20/60 V stepped potential (50 nm [two‐diameter]), and a 20–60 V swept potential (49 nm [full‐tapered]) (values in parentheses indicate the inner tube diameter at the top part of nanotube layers). The structures of the 50 nm (two‐diameter) and 49 nm (full‐tapered) samples had smaller inner diameters at the top part of nanotube layers than that of the 80 nm sample, while the outer diameters at the bottom part of nanotube layers were almost the same size as the 80 nm sample. The 80 nm sample, which had the largest nanotube diameter and length, exhibited the greatest burst release, followed by the 50 nm (two‐diameter), 49 nm (full‐tapered), and 45 nm samples. The initial burst released drug amounts and release rates from the 50 nm (two‐diameter) and 49 nm (full‐tapered) samples were significantly suppressed by the smaller tube top. On the other hand, the largest proportion of the slow released drug amount to the total released drug amount was observed for the 50 nm (two‐diameter) sample. Thus, 50 nm (two‐diameter) achieved suppressed initial burst release and large storage capacity. Therefore, this study has, for the first time, applied TiO2 nanotube layers with modulated diameters (two‐diameter and full‐tapered) to the realization of a localized drug delivery system (LDDS) with customized drug release properties.

Nonmetallic-Based Tubulars Provide Superior Integrity, Cost Savings

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 214647, “Operational Experience From the Implementation of 21 Wells With Nonmetallic-Based Downhole Tubing: From Pilot to Large-Scale Implementation,” by Mohamad H. Ahmad, ADNOC. The paper has not been peer reviewed. _ Tubular glass-reinforced-epoxy (GRE) lining technology has been applied globally since the 1960s in eliminating downhole tubular corrosion. Compared with conventional carbon steel, which can experience frequent failure, GRE-lined carbon steel provides long-lasting protection, resulting in huge savings in life-cycle cost. The operator implemented this technology for a successful trial of water-disposal wells. In the complete paper, the authors share the data from caliper logs run into, and the inspection of tubing pulled from, these disposal wells after 4 years in service. Tubular Corrosion in Operator Assets A growing emphasis on water disposal was inevitable because so much water was being produced with increased water cut and production. ADNOC Onshore operates almost 200 water-disposal wells. However, corrosion has been a common problem in these wells, such that a failure has been reported every 1–2 years. Use of corrosion-prone carbon steel for disposal strings has led to integrity issues and the need for expensive workover jobs that could cost between $1.5 million and $2 million per job. Fiberglass GRE Lining Since 2014, the operator has run 19 water-disposal wells with GRE-lined carbon steel strings. No failures have been reported, and inspections have been successful. Fiberglass tubular lining protects the internal surface of the tubing or casing inside the steel joint. Cement is pumped into the annulus between the GRE-liner outer diameter (OD) and the steel‑pipe inner diameter (ID). The final product is a completely corrosion-protected string, even under the connection area, where accessories called flares and corrosion barrier rings (CBRs) are installed (Fig. 1). The mechanical capability of the system is maintained by the steel pipe, while the internal fiberglass liner provides reliable corrosion resistance. Fiberglass Liner. The fiberglass liner shows excellent resistance in corrosive environments. As per tested and as per the manufacturer’s data sheets, the fiberglass lining system can be used in temperatures of up to 145°C, depending on hydrogen sulfide and CO2 levels in the flowing fluid. Besides being corrosion‑resistant, fiberglass lining improves the flow rate of the flowing water or oil because of the superior surface-energy properties and manufacturing quality of the liner material. The thickness of the liner varies according to the tubing size (diameter). Cement. The cement transfer applies pressure directly to the steel pipe. The cement does not bond the fiberglass liner to the steel and allows relative micromovement between the fiberglass liner and the steel pipe resulting from the difference in the thermal expansion coefficient of these two materials. Being alkaline, the cement tends to neutralize the possible presence of acid gases migrating in the fiberglass‑steel annulus; this further reduces the possibility of carbon-steel-pipe corrosion.

A Three-Dimensional Substation Reconstruction Method Based on Scenery Point Clouds

Abstract 3D modeling is the technical foundation for 3D visualization of substations, and accurate 3D panoramic modeling of substations is the key to achieving intelligent operation and maintenance of substations. However, the reuse rate of the model is low, resulting in low system modeling efficiency and bad model accuracy, which cannot fully leverage the advantages of 3D real scenery reconstruction technology. To address the aforementioned problems, this paper proposes a basic process and method for constructing a 3D model of a substation based on point cloud data, and provides an example of 3D reconstruction of the substation, which is then validated from three aspects. The experiment shows that the proposed process and method can achieve complete and accurate 3D reconstruction of substations, with a detail completeness of 98% and an outer diameter error of only 0.13 mm for transformer bushing leads.

Study on the effect of geometry and material property on collapse pressure of a helical steam generator tube under external pressure

In this paper, a numerical study was conducted to analyze the effect of the geometry (tube thickness, ovality, and helical diameter) and material properties of once through steam generator tubes subjected to external pressure on collapse pressure. The outer diameter of the steam generator tube was fixed at 17 mm, and the tube thickness was changed to 2.5 mm, 2.29 mm, and 1.27 mm. Ovality was considered for three cases of 0 %, 4 %, and 8 %, and three cases for helical diameter were considered: 577 mm, 937 mm, and 1297 mm. As material properties, elastic perfectly plastic property that ignores plastic hardening and real material property that reflect plastic hardening were considered. At the helical diameter (Dm/do ≥ 34) considered in this paper, the effect of collapse pressure due to helical bending did not appear on ovalities and both material properties. On the other hand, the wall thickness affected the collapse pressures according to the material properties when ovality occurred (>0 %). This is explained because the collapse mechanism varies depending on the thickness.

Experimental Investigation of Material Flow and Welding defects in Friction Welding process of Cu-SS Dissimilar Materials

Abstract: A particular form of welding that makes use of the heat produced by friction is called friction welding. A pressure force contacts the surfaces of two materials that need to be connected; one is rotating while the other is at rest. In order for the heat produced by the continuous friction to continue rising, friction is applied continually to the second contact surface. In this study, dissimilar friction welding between grade 308 L stainless steel (SS) and copper (Cu) is investigated for a pipe joint design with a wall thickness of 1.50 mm and an outer diameter of 13 mm. The machine RPM, dwell duration, friction time, and friction force are the constant parameters that are used. The maximum ultimate tensile strength of 764 MPa, or almost 128% of the SS base material, was found in the SS to SS weld sample and 104 MPa, or nearly 80% of the Cu basis material, in the CU to CU weld sample. The most significant maximum tensile strength of 349 MPa was achieved by SS to Cu. In along with the study of the mechanical behavior and microstructure, the weld quality was evaluated using corrosion behavior analysis and leak proof testing.

Analysis of variance and grey relational analysis application methods for the selection and optimization problem in 6061-T6 flange friction stir welding process parameters

A study was carried out to investigate and enhance the effects of friction stir welding on the mechanical characteristics of a flange composed of 6061-T3 aluminum alloy. The pipes possess an outer diameter and wall thickness of 6 mm, while the plates are sized at 100 x 100 × 6 mm. Nine unique experiments were planned using the Taguchi orthogonal array method, with the welding tool remaining constant. Three independent variables (travel speed, rotation speed, and shoulder diameter) were altered at three different levels for each variable. The research analyzed the influence of various FSW factors on the weld flange joint. Analysis of variance (ANOVA) and grey relational analysis (GRA) were employed to determine the impact of each FSW underwater parameter. Moreover, the statistical Taguchi technique (TM) was used to predict the optimal combination of welding parameters to improve tensile properties, including tensile strength (UTS), yield strength (YS), elongation (EI%), and bending load (BL) of welded joints. Additionally, the actual tests demonstrated a high level of agreement with the results obtained from the proposed mathematical model. The validation results obtained indicate that the optimization method is a dependable tool for enhancing the quality responses of friction stir welding.