Body Panels Research Articles

Fabrication of durable superhydrophobic Mg alloy surface with water-repellent, temperature-resistant, and self-cleaning properties

Superhydrophobic surfaces have superiority in the manufacturing of engineered materials and have attracted considerable interest because of their water-resistant and self-cleaning properties. However, variations in temperature and complex environments limit their use particularly in self-cleaning windows, automobiles, and aircraft body panels. In this work, durable superhydrophobic surfaces were fabricated on a Mg alloy through an electrochemical etching method using NaCl and NaNO3. The contact angle of the superhydrophobic surface was up to 162.1°, and the sliding angle was only 3°. Interestingly, the surfaces were superhydrophobic and thus exhibited excellent water-repellent performance even when impacted by droplets or continuous water jet at a wide range of temperatures. Furthermore, the superhydrophobic surfaces have desirable temperature resistance, which is up to 260 °C owing to the thermal stability of the microstructures and the fluoroalkylsilane (FAS) film. Scanning electron microscopy (SEM) result demonstrates that the microstructures have good thermal stability, and X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectrometry (FTIR) confirm the stable FAS film. The prepared surfaces maintain exceptional self-cleaning properties after alternating-temperature treatment. This work presents a facile strategy for fabricating superhydrophobic surfaces with excellent water-repellent, temperature-resistant, and self-cleaning properties and demonstrates its great potential in practical applications.

Infrared contrast characteristic of satellites

Using infrared characteristic of space target for detecting and identifying the space target is a kind of effective method. Infrared radiation contrast study of satellite has great significance for both detecting and identifying the satellite, and monitoring satellite condition. In this paper, the method to calculate the radiant heat flux of satellite is given firstly. Then, the mathematical model of the surface temperature of satellite is obtained and the numerical calculation is done. The calculated numerical data is similar to the telemetry data, which proves that the orbit flux and temperature models are correct. Finally, the infrared radiant contrast of every surface on the satellite’s body and solar panels were calculated and analyzed. The results show that, on the one hand, satellite infrared radiation in long wave infrared band is larger than that in medium wave infrared band. From the point of view of the range coverage, use the long wave infrared is more advantageous to detect satellite. And on the other hand, satellite infrared contrast in medium wave infrared band is much larger than that in long wave infrared band. From the point of view of the resolution of image detail, use the medium wave infrared is more advantageous to identify satellite.

低コヒーレンスディジタルホログラフィを用いた車体用ボディパネル中の光輝材分布の評価

低コヒーレンスディジタルホログラフィを用いた車体用ボディパネル中の光輝材分布の評価

Contact Area Evaluation of Digitalized Spotting Images as a Criterion for Die Tryout

Increasing demands on the quality of outer car body panels and shortened product development processes of car models fundamentally challenge automotive manufacturers concerning international competition. In this respect, the tryout process carried out during the manufacturing of dies requires special consideration. Die tryout is generally characterized by time-consuming manual grinding operations aimed at producing homogeneous contact areas of the die surface zones. Here, blue color paste visualizes the contact areas of the dies and provides a spotting image. Afterward, the toolmaker uses his experience to qualitatively evaluate the different spotting images on both sides of the die and the blank in order to rework the tool surfaces appropriately. In this context, this paper presents a new approach for evaluating spotting images by using optical measurement technology and image processing. The method leads to a measurable quantitative size during the tryout of dies and standardized evaluation. For this, the active contact areas of die components are measured first in order to compare the current die performance with the forming simulation subsequently. Thus, a specific tryout state can be numerically defined, leading to a shorter and more efficient tryout by reducing manual grinding processes. During the investigations presented in this paper, spotting images of series dies were analyzed by implementing an image processing tool. Furthermore, a threshold value specification for the blue color of the measured spotting images was defined in order to distinguish between active and non-active contact areas.

Surface development by reinforcing nano-composites during friction stir processing – a review

PurposeFriction stir processing (FSP) is overviewed with the process variables, along with the thermal aspect of different metals.Design/methodology/approachWith its inbuilt advantages, FSP is used to reduce the failure in the structural integrity of the body panels of automobiles, airplanes and lashing rails. FSP has excellent process ability and surface treatability with good corrosion resistance and high strength at elevated temperatures. Process parameters such as rotation speed of the tool, traverse speed, tool tilt angle, groove design, volume fraction and increase in number of tool passes should be considered for generating a processed and defect-free surface of the workpiece.FindingsFSP process is used for modifying the surface by reinforcement of composites to improve the mechanical properties and results in the ultrafine grain refinement of microstructure. FSP uses the frictional heat and mechanical deformation for achieving the maximum performance using the low-cost tool; the production time is also very less.Originality/value100

Finite Element and Experimental Analysis of the preheating stage of High Speed Blow Forming (HSBF) process

High-Speed Blow Forming (HSBF) is a new manufacturing technology based on superplastic forming for the production of complex shape thin sheet of aluminum alloys for electrical car body panels. A major challenge for the full scale industrialization of the process in automotive industry is to reduce the overall HSBF processing time while keeping temperature distribution as uniform as possible on the dies. In this study, the thermal mapping of the dies during the preheating cycle (also known as offline heating) of a HSBF process was investigated using a hybrid experimental-numerical method with a view to minimizing the preheating time and to obtain a uniform temperature distribution on the dies surfaces at the end of the preheating cycle. To this end, the upper and lower dies of an industrial size part were instrumented with 14 thermocouples at different locations of the dies. The process was simulated using the finite element software ABAQUS to predict the temperature evolution over the entire surfaces of the dies from room temperature to the target temperature. The predictions were validated by comparison with the experimental measurements. Based on the obtained results a new offline heating cycle insuring minimum discrepancy in temperature distribution and minimum processing time is proposed.

Simultaneously enhanced strength and ductility of 6xxx Al alloys via manipulating meso-scale and nano-scale structures guided with phase equilibrium

Excellent comprehensive mechanical properties including good formability, high strength and high ductility are prior demands for Al-Mg-Si-Cu alloys. This study utilizes calculation of phase diagram (CALPHAD) to simplify the alloy design and meet these demands. Specifically, CALPHAD was used to finely tune the Mg/Si atomic ratio in solid solution and accurately control the type and content of second phases, especially to avoid the formation of the harmful constituent phase β-AlFeSi. Constituents and dispersoids of only α-AlFeMnSi phase were found in the alloy prepared. An optimized microstructure with fine grains, micro scale constituents, densely distributed submicron scale dispersoids and extremely dense nano precipitates provides effective impediment to dislocation gliding and induces transgranular fracture. Therefore, the designed alloy has better comprehensive mechanical properties than other 6xxx series aluminum alloys, including excellent formability, strength and ductility. The low T4P strength of 149 MPa as well as the high elongation of 26.1% implies the alloy's applicability to automobile body panel forming. The yield strength was rapidly improved from 149 MPa to 277 MPa during the paint bake ageing, because the number density of precipitates is twice as high as that of some other 6xxx alloys. Meanwhile, the elongation was kept at a high level of 20.0%.

Digital process support in toolmaking by using optical metrology

Increasing demands on the quality of outer skin car body panels, shortening product development processes of new car models in the future fundamentally challenge manufacturing companies in international competition. Such challenges emerge, for example, in the field of toolmaking, which plays a decisive role in the valueadded chain due to its high time and costs share. Here, the high proportion of manual, experiencebased operations in tool tryout often leads to unstable processes requiring many iteration steps until approval. Blue, non-dry colour is applied on sheet metal which creates a spotting image that makes the contact areas between the forming die surface visible. In die tryout, spotting images provide a visual indication of the current phase and also serve as quality criteria of sheet metal components. For this reason, research work reported about in this paper deals with the development of a procedure for generating digital spotting images by using optical 3D coordinate-measuring technology to keep the spotting image permanently available during die tryout phase, for example on smart devices. In fundamental investigations, different influences on the spotting image due to light conditions and STL-mesh size of the scanned geometry are initially examined in order to quantify both the physical and the digital spotting image. The knowledge gained is subsequently validated and further improved by means of test with series press tools. The results demonstrate how digital and physical spotting images are generated and quantified for a reduced time in sheet metal simulation and die tryout phase of large press tools. This is achieved by the systematic provision of process parameters from the series production, such as the force transmission between the forming die surfaces, the local sheet thicknesses and the documentation of process variation in the blank holder by using digital spotting images.

Review of Morphing Laminated Composites

Abstract Morphing structures, defined as body panels that are capable of a drastic autonomous shape transformation, have gained importance in the aerospace, automotive, and soft robotics industries since they address the need to switch between shapes for optimal performance over the range of operation. Laminated composites are attractive for morphing because multiple laminae, each serving a specific function, can be combined to address multiple functional requirements such as shape transformation, structural integrity, safety, aerodynamic performance, and minimal actuation energy. This paper presents a review of laminated composite designs for morphing structures. The trends in morphing composites research are outlined and the literature on laminated composites is categorized based on deformation modes and multifunctional approaches. Materials commonly used in morphing structures are classified based on their properties. Composite designs for various morphing modes such as stretching, flexure, and folding are summarized and their performance is compared. Based on the literature, the laminae in an n-layered composite are classified based on function into three types: constraining, adaptive, and prestressed. A general analytical modeling framework is presented for composites comprising the three types of functional laminae. Modeling developments for each morphing mode and for actuation using smart material-based active layers are discussed. Results, presented for each deformation mode, indicate that the analytical modeling can not only provide insight into the structure's mechanics but also serve as a guide for geometric design and material selection.

A study on sheet metal hemming process

Hemming is a sheet metal forming process in which sheets are joined by bending it usually to 180°. Automotive body panels and automotive parts such as deck-lids, trunk-lids, doors, hoods and tailgates are formed by hemming process. This paper present a systematic review of sheet metal hemming process based on materials used in hemming process, analytical models, experimental and computational investigations made in the domain of sheet metal hemming process. Various grades of high strength sheets, aluminium alloys, recycle-friendly aluminium alloys, magnesium alloys, light weight alloys are used as workpiece materials in hemming process. Analytical models are also presented by few researchers for development in hemming process. New experimental set-up and novel experimental strategies of hemming process are devised and also adopted by researchers in past. Classical hemming, roller hemming, robot assisted roller hemming, laser assisted roller hemming and hemming with electromagnetic forming processes are the experimental different approaches utilized for performing sheet metal hemming operations. In FEM simulation of hemming process, three dimensional solid elements, shell elements and their combination are mostly employed by researchers in meshing of sheet metal blanks in hemming process. FEM simulation found to be an efficient tool for prediction of defects in hemming process and for optimization of process parameters as well. Besides, FEM simulation new computational approaches such as meta-model strategy are also applied for efficient design of hemming process.

Study of structural optimization design on a certain vehicle body-in-white based on static performance and modal analysis

Abstract The intensity analysis was proposed for a certain all-aluminum vehicle body-in-white, and an optimistic method of the vehicle body was carried out based on lightweight target. The finite element model of vehicle body-in-white was established, and the flexural rigidity and torsional rigidity of the vehicle body are calculated according to the actual operating conditions of the vehicle. The flexural rigidity and torsional rigidity of the vehicle body are calculated, and the main opening deformation of the vehicle body under these two working conditions was studied. Finally, based on the thickness of the body panel, the structural sensitivity analysis of the vehicle body was carried out. According to the sensitivity analysis data, the optimization variable is determined with lightweight as the target, and the vehicle body structure is optimized. The results showed that the static and dynamic performance indexes of the white body were higher than the standards of similar motorcycle type at home and abroad, the bending stiffness of the structurally improved basic model after sensitivity optimization was reduced by 2.1% compared with before optimization, but still much higher than the target reference value (122,000 N/mm). And the quality of the vehicle body was reduced, which met the lightweight requirements of optimized design after the optimization of the thickness of the improved basic model.

Characterization of Fiber Metal Laminates, Bonding and Manufacturing Methods

Materials having low density combined with superior strength are gaining demand in the field of automobiles, aeronautical and military appliances. Fiber Metal Laminates (FML) is becoming the material of choice for the above mentioned applications because of the ability to tailor it to meet the demands of the end applications. This paper throws light on the commercially available for of FMLs, its production methods, property enhancement and diverse applications. As such Carbon fibre reinforced composite are preferred for making automobile bonnets and fuselage in military aircraft due to the superior strength to weight ratio. On the other hand glass fiber reinforced composite materials are used to manufacture railway locomotive body panels due to the high tensile strength and impact strength. This paper can be used as reference for budding engineers who want to gain first-hand knowledge on FMLs.

자동차 차체 경량화를 위한 알루미늄 5182-폴리프로필렌 샌드위치 판재의 상용화 기술 개발

An aluminium sandwich sheet is the composite adhered by rolling two aluminum panels to one plastic core. If it has the same bending stiffness as an steel sheets, it is about 65% lighter than steel sheet and 30% lighter than aluminum sheet. In present study, we intend to develop application technologies of an aluminum sandwich sheet for auto body panels from selecting composed materials of aluminium sandwich sheets to fabricating prototype. For this study, for the application of a light sandwich sheet to an automotive hood part, ribbing process so called, hemming for which joined between an inner and an outer panel was introduced. From these results, it was found that the sandwich sheet could improve the weight and maintain the flexural rigidity simultaneously comparing to the steel sheet.

Crashworthiness of automobile made of HDPE/kenaf and HDPE/MWCNT polymer composites

The present work deals with the crashworthiness of high-density polyethylene/kenaf and high-density polyethylene/multi-walled carbon nanotube polymer composites. The purpose of using polymer composites for the crashworthiness is their high specific energy absorption due to the low weight of the polymer composites. The various mechanical properties (Young’s modulus, tensile yield strength, and ultimate tensile strength) of the stated polymer composites have been predicted by a uniaxial tensile test. Further, these properties have been used as the input for the crash simulation. A widely known finite element method (FEM) package ANSYS has been used for the crashworthiness of the automobile. In the present study, HDPE/kenaf and HDPE/MWCNT polymer composites with 20 wt. % of reinforcement have been considered. The CAD geometry of automobile structure is modelled in SolidWorks and further analyze in ANSYS-explicit dynamics. Numerical results are presented in the form of equivalent (von Mises) stress and directional deformation of the automobile’s body panel with respect to time. It has been observed that the body panel made of HDPE/kenaf polymer composite induces relatively higher magnitude of equivalent (von Mises) stress and lower directional deformation by 42.85 %.

Processability study of in‐mold coating for sheet molding compound compression molded parts

In‐mold coating (IMC) is applied to compression molded sheet molding compound (SMC) exterior automotive or truck body panels as an environmentally friendly primer to make the part conductive for subsequent electrostatic painting operations. The coating is a thermosetting liquid that when injected onto the surface of the part cures and bonds to provide a smooth conductive surface. In order to identify the processability of IMC for SMC, it is essential to predict the time available for flow, that is the time before the viscosity starts to increase as well as the time when the coating has enough structural integrity so that the mold can be opened without damaging the part surface (mold opening time). In the present work, we study cure behavior of IMC based on differential scanning calorimetry and rheological experiments and show its relevance to both flow and mold opening time for the IMC process during SMC compression molding. POLYM. ENG. SCI., 59:1688–1694 2019. © 2019 Society of Plastics Engineers

Evaluation and Visualization of surface Defects on Automotive Body Panels by Root-Cause Methodology

Evaluation and Visualization of surface Defects on Automotive Body Panels by Root-Cause Methodology

Decreasing the cycle time for in‐mold coating (IMC) of sheet molding compound (SMC) compression molding

In‐mold coating (IMC) is a thermosetting liquid applied to compression molded sheet molding compound (SMC) exterior automotive or truck body panels as an environmentally friendly primer to improve surface quality and make the part conductive for subsequent electrostatic painting. The IMC is injected onto the surface of the SMC then cures and bonds to provide a smooth conductive and protective surface. In IMC as in many other reactive polymer processes, to have short cycle time while maintaining adequate flow time and pot life is required. This allows enough time to fill the mold before solidification. In this study, the effect of inhibitor (p‐benzoquinone), initiator (t‐butyl peroxybenzoate), and mold temperature on the flow and cure time of IMC materials has been experimentally investigated using differential scanning calorimeter. A cure model is developed based on experiments to predict inhibition and cure time. A multiple criteria optimization method was employed to identify the setting parameters of the controllable process variables that provide the best compromise (Pareto frontier [PF]) between flow and cure time. The analysis shows that simultaneous addition of initiator and inhibitor allows the molding to be performed at a higher temperature, which moves the PF toward the ideal location. Hence, minimizes the cure time and maximizes the flow time simultaneously. POLYM. ENG. SCI., 59:1158–1166 2019. © 2019 Society of Plastics Engineers

An optical-based technique to obtain operating deflection shapes of structures with complex geometries

Abstract The dynamic characteristics of structures are conventionally obtained by exciting the structure using an impulse hammer or a mechanical shaker and measuring the response using uniaxial or multi-axial accelerometers. However, contact-based sensors can mass-load the structure and do not provide full-field data. Hence, obtaining the true dynamics of the structure using conventional sensors can be challenging. That makes test engineers seek different non-contact techniques that can provide full-field data without mass-loading the structure. Recently, stereo-photogrammetry and three-dimensional digital image correlation (3D DIC) have been adopted to collect operating data for structural analysis. These non-contact optical techniques provide a wealth of distributed data over the entire structure. However, the stereo-camera system is limited by the field-of-view of the cameras; a single pair of DIC cameras may not be able to provide deformation data for the entire structure. Hence, it is challenging to obtain the vibration characteristics of the entire structure. In the current work, a multi-view 3D DIC approach is used and validated to predict the vibrational characteristics of an automotive muffler with a complex structure. A pair of DIC cameras travels over the entire structure to capture the deformation of each field of view. The measured data includes the geometry and displacement data, which is later mapped into a global coordinate system. The measured data in the time domain for each field-of-view is transformed to the frequency domain to extract the operational deflection shapes and resonant frequencies for each field of view. The obtained deflection shapes are stitched together in the frequency domain to extract the operating deflection shapes and resonant frequencies of the automotive body panel with a complex structure.

Research on Lightweight Design of CFRP Engine Hood

Vehicle lightweight technology has become an important means to solve the fuel economy and environmental protection of vehicles. Carbon fiber reinforced polymer (CFRP) is the best lightweight material for body. The main objective of this paper is to apply CFRP to body panels (hood), the basic performances of CFRP hood were studied by finite element simulation and sample test, Exploring the feasibility of replacing CFRP parts with steel parts and testing its lightweight effect.

Forming Quality Control of an AA5182-O Aluminum Alloy Engine Hood Inner Panel

The poor formability of aluminum alloys at room temperature easily leads to quality defects such as ruptures, wrinkles and excessive springback after forming, which severely restricts their wide application in the automotive industry. In this article, a combination of springback compensation and process parameter optimization is proposed to improve the forming quality of aluminum alloy auto body panels. First, the springback compensation for the tooling setting was conducted using the global shape modeling (GSM) function in ThinkDesign to ensure the desired dimensional quality of the hood. Then, the process parameter optimization was conducted based on the combination of a back-propagation (BP) neural network and genetic algorithm (GA) method to improve formability. After springback compensation and process parameter optimization, the obtained product could satisfy the matching requirements well. A case study of an AA5182-O aluminum alloy engine hood inner panel is presented. The experiments demonstrate that the combination of the springback compensation and the optimization scheme based on the BP neural network and GA can effectively improve the product’s forming quality.