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Abstract Additive manufacturing (AM) technologies can produce lighter parts; reduce manual assembly processes; reduce the number of production steps; shorten the production cycle; significantly reduce material consumption; enable the production of prostheses, implants, and artificial organs; and produce end-user products since it is used in many sectors for many reasons; it has also started to be used widely, especially in the field of aerospace. In this study, polylactic acid (PLA) was preferred for the antenna substrate because it is environmentally friendly, easy to recycle, provides convenience in production design with a three-dimensional (3D) printer, and is less expensive compared to other available materials. Copper (Cu) tape and graphene filament were employed for the antenna patch component due to their benefits.

Abstract With the introduction of advanced lightweight materials with complex microstructures and behaviors, more focus is put on the accurate determination of their forming limits, and that can only be possible through experiments as the conventional theoretical models for the forming limit curve (FLC) prediction fail to perform. Despite that, CAE engineers, designers, and toolmakers still rely heavily on theoretical models due to the steep costs associated with formability testing, including mechanical setup, a large number of tests, and the cost of a stereo digital image correlation (DIC) system. The international standard ISO 12004-2:2021 recommends using a stereo DIC system for formability testing since two-dimensional (2D) DIC systems are considered incapable of producing reliable strains due to errors associated with out-of-plane motion and deformation.

Abstract Three-dimensional patterns representing crosshatched plateau-honed cylinder bores based on two-dimensional Fast Fourier Transform (FFT) of measured surfaces were generated and used to calculate pressure flow, shear-driven flow, and shear stress factors. Later, the flow and shear stress factors obtained by numerical simulations for various surface patterns were used to calculate lubricant film thickness and friction force between piston ring and cylinder bore contact in typical diesel engine conditions using a mixed lubrication model. The effects of various crosshatch honing angles, such as 30°, 45°, and 60°, and texture heights on engine friction losses, wear, and oil consumption were discussed in detail. It is observed from numerical results that lower lubricant film thickness values are generated with higher honing angles, particularly in mixed lubrication regime where lubricant film thickness is close to the roughness level, mainly due to lower resistance to pressure flow.

Abstract Maximum lifetime and minimum manufacturing cost for new products are the primary goals of companies for competitiveness. These two objectives are contradictory and the geometric dimensions of the products directly control them. In addition, the earlier design errors of new products are predicted, the easier and more inexpensive their rectification becomes. To achieve these objectives, we propose in this article a novel model that makes it possible to solve the problem of optimizing the lifespan and the manufacturing cost of new products during the phase of their design. The prediction of the life of the products is carried out by an energy damage method implemented on the finite element (FE) calculation by using the ABAQUS software. The manufacturing cost prediction is carried out by applying the ABC cost estimation analytical method. In addition, the optimization problem is solved by the method of genetic algorithms.

Abstract Electromagnetic forming (EMF) is a high-speed impulse forming process developed during the 1950s and 1960s to acquire shapes from sheet metal that could not be obtained using conventional forming techniques. In order to attain required deformation, EMF process applies high Lorentz force for a very short duration of time. Due to the ability to form aluminum and other low-formability materials, the use of EMF of sheet metal for automobile parts has been rising in recent years. This review gives an inclusive survey of historical progress in EMF of continuum sheet metals. Also, the EMF is reviewed based on analytical approach, finite element method (FEM) simulation-based approach and experimental approach, on formability of the metals.

Abstract Gasoline particulate filters (GPFs) are important aftertreatment components that enable gasoline direct injection (GDI) engines to meet European Union (EU) 6 and China 6 particulate number emissions regulations for nonvolatile particles greater than 23 nm in diameter. GPFs are rapidly becoming an integral part of the modern GDI aftertreatment system. The Active Exhaust Tuning (EXTUN) Valve is a butterfly valve placed in the tailpipe of an exhaust system that can be electronically positioned to control exhaust noise levels (decibels) under various vehicle operating conditions. This device is positioned downstream of the GPF, and variations in the tuning valve position can impact exhaust backpressures, making it difficult to monitor soot/ash accumulation or detect damage/removal of the GPF substrate. The purpose of this work is to present a unique example of subsystem control and diagnostic architecture for an exhaust system combining GPF and EXTUN.

Abstract Point cloud objects have gained popularity in three-dimensional (3D) printing recently due to advancements in reverse engineering technology. Fabricating an object with a fused deposition modeling (FDM) printer requires converting the object to layered contours, which involves a slicing process. The slicing process of a point cloud object usually requires reconstructing a 3D object from a point cloud, which requires users’ deep understanding of 3D modeling software and a laborious work process. To avoid these problems, the direct slicing of point cloud objects is gaining more popularity. This research work proposes an adaptive slicing approach from point cloud objects directly without surface reconstruction. The adaptive slicing maintains the global geometry error while requiring a smaller number of fabrication layers and printing time. A new error profile used in the adaptive slicing approach is introduced.

Abstract An innovative analysis approach to evaluate heavy-duty vehicle downhill engine brake performance was developed. The vehicle model developed with GT-Drive simulates vehicle downhill control speeds with different engine brake retarding powers, transmission gears, and vehicle weights at sea level or high altitude. The outputs are then used to construct multi-factor parametric design charts. The charts can be used to analyze the vehicle-level engine brake capabilities or compare braking performance difference between different engine brake configurations to quantify the risk of engine retarding power deficiency at both sea level and high altitude downhill driving conditions.

Abstract The variation of inflation pressure has an important effect on the longitudinal slip characteristics of tires that can affect the braking performance of the vehicle, so the influence of inflation pressure should be taken into account in high-precision tire models. However, the effects of inflation pressure and vertical load on tire force and moment characteristics are usually coupled. When the inflation pressure is changing while keeping the load constant, the tire contact patch and carcass stiffness will change at the same time, so the contribution of tread and carcass to tire traction properties cannot be decoupled so that the tire design cannot be well guided. On the contrary, if the vertical loading method is changed, the vertical deflection control is used instead of load control.

Abstract This study predicts the dynamic characteristics for tires in the development stages of a vehicle with a focus on the generated forces. In particular, this investigation proposes an approximation analysis for the deflection and contact characteristics of a pneumatic tire. This consists of an integrated model for a three-dimensional membrane ring and brush models. This model is more complex than conventional models, which resulted in increased computational costs. Because the tire dynamic characteristics affects the contact pressure, the deformation of the tread rubber caused an interaction of forces. Therefore, the tread ring deformation was defined as a summation of the mode basis functions, which expressed vibrational behavior. This approximation linearizes the energy function, which helped calculate the potential energy of the tire structure using a theoretical equation without discretization.

Abstract New analytical structural stress solutions for a rigid inclusion in a finite square thin plate with clamping edges under opening loading conditions are developed. The new solutions are used to derive new analytical structural stress and stress intensity factor solutions for similar and dissimilar spot welds in cross-tension specimens. Three-dimensional finite element analyses are conducted to obtain the stress intensity factor solutions for similar spot welds and dissimilar magnesium/steel spot welds in cross-tension specimens of equal thickness with different ratios of half-specimen width-to-weld radius. A comparison of the analytical and computational solutions indicates that the analytical stress intensity factor solutions for similar spot welds in cross-tension specimens of equal thickness are accurate for large ratios of half-specimen width-to-weld radius.

Abstract The aim of this work is to present the results achieved in the evaluation of combustion metrics using low-cost sensors for the indirect measurement of cylinder pressure. The developed transducers are piezoelectric rings placed under the spark plugs. Tests were carried out on three different engines running in various speed and load conditions. The article shows the characteristics of the signals generated by the piezo-ring sensors, compared to those coming from laboratory-grade pressure transducers: focus is to assess the achievable accuracy in the determination of frequently used combustion metrics, such as those related to knock intensity (Maximum Amplitude of Pressure Oscillations, MAPO), combustion phasing (MFB10, MFB50, …), and peak pressure.

Abstract The manufacturing of diesel injector nozzles requires precision processing to produce multiple micro-holes. An abrasive fluid containing a mixture of mineral oil and hard particles is used for rounding them, ensuring the hydrodynamics of the injection. As verified in a previous investigation, the viscosity of the fluid undergoes uncontrolled changes during hydro-erosive (HE) grinding. Such undesired viscosity changes are detrimental to the process and difficult to assess. The current investigation aims to study the possibility of using the refractive index of the oils used in the HE grinding for assessing their viscosities. A calibration curve correlating the refractive index and viscosity was obtained from the analysis of samples produced by mixing two distinct mineral oils in different proportions. The determined calibration curve was tested with 45 samples of filtered oil, collected directly from the tanks during the HE grinding.

Abstract Single point incremental forming (SPIF) is a robust and new technique. In the recent research scenario, materials properties such as microstructure, micro-texture analysis, and crystal structure can be accessed through characterization non-destructive techniques, e.g., scanning electron microscope (SEM), electron backscattered diffraction (EBSD), and X-ray diffraction (XRD). XRD is a non-destructive method for analyzing the fine structure of materials. This study explores how process variables such as wall angle, step size, feed rate, and forming speed affect the parts of large-, medium-, and small-sized truncated cones of aluminum alloy AA3003-O sheet. Several cone parts of truncated cones are used in this investigation to implement Scherrer’s method. The two primary determining factors peak height and crystallite size are assessed for additional analysis in the present research.

Abstract The paper presents a complete description of the design and manufacturing of a Carbon Fiber/epoxy mold with an embedded Carbon Fiber resistor heater, and the mold performances in terms of its surface temperature distribution and thermal deformations resulting from the heating. The mold was designed for manufacturing aileron skins from Vacuum Bag Only prepreg cured at 135°C. The glass transition temperature of the used resin-hardener system was about 175°C. To ensure homogenous temperature of the mold working surface in the course of curing, the Carbon Fiber heater was embedded in a layer of a highly heat-conductive cristobalite/epoxy composite, forming the core of the mold shell. Because the cristobalite/epoxy composite displayed much higher thermal expansion than CF/epoxy did, thermal stresses could arise due to this discrepancy in the course of heating.

Abstract The present study deals with the investigation on microstructural and mechanical properties of friction stir processed (FSPed) pure Aluminum (Al)-Graphene Nanoplatelets (GNPs) composites. Composite specimens such as castings were made by blending 0.5 wt.%, 1.0 wt.%, 1.5 wt.%, and 2.0 wt.% of GNPs in pure Al matrix using the ultrasonic-assisted stir casting technique (UASCT). Also for enhancement of mechanical properties via grain refinement the friction stir processing (FSP) has been employed, as well as mechanical properties like tensile strength and microhardness were evaluated. Moreover, the microstructural analysis were done using Scanning Electron Microscope (SEM), Field Emission Scanning Electron Microscope (FESEM), transmission electron microscopy (TEM), and X-Ray Diffraction (XRD) examination were also performed for inspecting the changes occurred during synthesis of the fabricated composites after FSP.

Abstract This paper presents a machine learning application of the force/torque sensor in a human-robot collaborative manufacturing scenario. The purpose is to simplify the programming for physical interactions between the human operators and industrial robots in a hybrid manufacturing cell which combines several robotic applications, such as parts manipulation, assembly, sealing and painting, etc. A multiclass classifier using Light Gradient Boosting Machine (LightGBM) is first introduced in a robotic application for discriminating five different contact states w.r.t. the force/torque data. A systematic approach to train machine-learning based classifiers is presented, thus opens a door for enabling LightGBM with robotic data process. The total task time is reduced largely because force transitions can be detected on-the-fly. Experiments on an ABB force sensor and an industrial robot demonstrate the feasibility of the proposed method.

Abstract High-cycle fatigue (HCF) is one of the main concerns for spot-welded structures, and finite element (FE)-based simulations have critical importance for the life assessment and design optimization. The accuracy of spot weld modeling methodologies has a key role in achieving the development objectives. This article presents a comparative study for HCF simulations of different spot weld modeling methodologies and their comparison with the test data. In this regard, HCF analyses based on Findley’s multi-axial damage model are conducted with a commercial software. Direct equivalenced spot weld modeling with and without offset adjustment, rigid spot weld, and rigid beam (single) spot weld methods are analyzed for overlapped sheet metals under axial cyclic loading. Two specimens with different thicknesses, spot weld diameters, and number of nuggets are simulated under six cyclic load cases: 2000-4000 N, 1400-2800 N, 1800-3600 N, 200-8000 N, 100-8300 N, and 200-6800 N.

Abstract Closed crankcase ventilation (CCV) systems are required in most automotive markets in order to meet emissions regulations. Such systems usually require a separator to recover oil and return it to the sump. Many end users fit improved separators in order to reduce intake/aftercooler contamination with soot/oil. This study measured clean and wet pressure drop and filter capture efficiency in 12 different crankcase oil mist separators which are commonly used for either original equipment (OE) or aftermarket fitment to passenger vehicles and four-wheel drives (≤200 kW). The filters tested spanned three different size/rating classes as well as included both branded and unbranded (imitation) models. In addition to filters, separators (often termed “catch cans”) and an OE cyclone separator were also examined. Testing was performed under controlled laboratory conditions using methods equivalent to previous work and current mist filter test standards.

Abstract Reducing a vehicle’s weight is an efficient method to reduce energy consumption. Aluminum alloy is the best material for lightweight automobiles. However, the poor formability of aluminum means that it is difficult to develop stamping dies. This study designs a suitable forming tool for aluminum fenders. A simulation and an experiment are used to analyze the formability of aluminum fenders. A theoretical calculation, experimental testing, and sampling comparison are used to verify the design. The material properties of steel and aluminum are firstly studied and compared. The results show that a traditional S-type blank die face design is not suitable for aluminum because of its low tensile strength and the potential for elongation. A relatively flat trapezoid blank die face design is proposed to smooth the variation. However, a flat die face for a trapezoidal blank limits stretching, so another design is essential to improve the formability.