Enabling circular engineering by redesigning a driver’s side front door using ultralightweight thermoplastics composites via systems level design and simulation strategy

Greenhouse gases are one of the primary causes of human induced global warming wherein ~14% of the global greenhouse gas emissions are from the transportation sector. This underscores the vast potential and impact any sustainable paradigm might bring if tailored to the practical realities of the automotive sector. In this context a closed loop multicycle paradigm that goes beyond the reduce, reuse and recycle dogma and emphasizes on the redesigning and remanufacturing of vehicles aka Circular Engineering might just be the solution the automotive sector needs. A great case for circular engineering can be presented in the context of lightweighting of the automotive structures that would: reduce the weight of the car and material usage, translating to greater fuel efficiency but come coupled with engineering challenges ranging from design to manufacturing. From a materials perspective carbon fiber reinforced thermoplastic composites offer an alluring premise as they provide high stiffness and strength while being lightweight and are recyclable when compared to their thermoset counterparts. However, a major constraint to their immediate adoption include: Understanding their failure behavior in nonlinear crash environments, cost of carbon fiber and cycle time for production. This work looks into incorporating the principles of circular engineering by delving into the process of designing an ultralightweight thermoplastic composites door (a driver’s side front door) and developing robust simulation methods to validate and optimize its crash response. This includes details on the development of robust material cards and their experimental validation at coupon and component level. These robust simulation methods form the cornerstone to rapidly iterate and develop a composite door frame that meets and surpass the crash performance of the baseline metal door

Thermoplastics Foams: An Automotive Perspective

The automotive industry has witnessed a massive shift in terms of materials used, ranging from being a metallic heavyweight in the 1950s to employing a hybrid sandwich of multiple material systems. This apparent shift can be attributed to achieving improvements in performance, safety and fuel efficiency, along with responding to the various environmental regulations imposed by different governments. The recent advocacy of Corporate Average Fuel Economy (CAFE) standard of 54.5 MPG by 2025 by the US Environmental Protection Agency (EPA) to reduce greenhouse gas (GHG) emissions [1] has spurred the sector at large towards the use of lightweight materials

COMPOSITES 4.0: ENABLING THE MODERNIZATION OF LEGACY MANUFACTURING ASSETS IN SOUTH CAROLINA

Composites 4.0 is the implementation of Industry 4.0 concepts to plastics and composites manufacturing with the goal to overcome the complexities associated with these materials. Due to very complex process-structure-property relationships associated with plastics and composites, a wide range of process parameters need to be tracked and monitored. Furthermore, these parameters are often affected by the tool and machinery, human intervention and variability and should thus, be monitored by integrating intelligence and connectivity in manufacturing systems. Retrofitting legacy manufacturing systems with modern sensing and control systems is emerging as one of the more cost-effective approaches as it circumvents the substantial investments needed to replace legacy equipment with modern systems to enhance productivity. The goal of the following study is to contribute to these retrofitting efforts by identifying the current state-of-the-art and implementation level of Composites 4.0 capabilities in the plastics and composites manufacturing industry. The study was conducted in two phases, first, a detailed review of the current state-of-the-art for Industry 4.0 in the manufacturing domain was conducted to understand the level of integration possible. It also helped gain insights into formulating the right questions for the composites manufacturing industry in South Carolina. Second, a survey of the plastics and composites manufacturing industries was performed based on these questions, which helps identify the needs of the industry and the gap in the implementation of Composites 4.0. The study focuses on the three leading composite manufacturing industries: injection molding, extrusion, and 3D printing of thermoset and thermoplastic materials. Through the survey, it was possible to identify focus areas and desired functionalities being targeted by the industries surveyed and concentrate research efforts to develop targeted solutions. After analyzing the survey responses, it was found that updating old protocols using manufacturer support and customized integration of cost-effective solutions like retrofit kits, edge gateways, and smart sensors were identified as best-suited solutions to modernize the equipment. Composites 4.0 is already being implemented for Preventive Maintenance (PM), Manufacturing Execution System (MES), and Enterprise Resource Planning (ERP) to some extent, and the focus is on process optimization and equipment downtime reduction. The inferences drawn from this study are being used to develop highly targeted, supplier-agnostic solutions to modernize legacy manufacturing assets

Thermoforming process effects on structural performance of carbon fiber reinforced thermoplastic composite parts through a manufacturing to response pathway

Thermoforming process of thermoplastic-based continuous CFRP\u27s offer a major advantage in reducing cycle times for large-scale productions, but it can also have a significant impact on the structural performance of the parts by inducing undesirable effects. This necessitates the development of an optimal manufacturing process that minimizes the introduction of undesirable factors in the structure and thereby achieves the targeted mechanical performance. This can be done by first establishing a relationship between the manufacturing process and mechanical performance and successively optimizing it to achieve the desired targets. The current study focuses on the former part, where a manufacturing-to-response (MTR) pathway is established for a continuous fiber-reinforced thermoplastic composite hat structure. The MTR pathway incorporates the thermoforming process-induced effects while determining the mechanical performance and principally comprises of material characterization, finite element simulations, and experimental validation. The composite material system selected for this study is AS4/Nylon-6 (PA6) with a woven layup. At first, the thermoforming simulations are performed above the melt temperature of PA6 using an anisotropic hyperelastic material model, and the process-induced effects such as thickness variation, fiber orientations, and residual stresses are captured from the analysis. Residual stresses developed in the formed structure during quench cooling from the elevated temperature are predicted by the implementation of classical laminate theory (CLT). These results are then mapped onto a duplicate part meshed suitably for mechanical performance analysis. A quasi-static 3-point bend test and a dynamic impact test are carried out and the results are compared with experimental tests. Experimental results from thermoforming, bending and dynamic impact trials show good agreement with the simulation results for the hat structure under consideration. Further, the static and dynamic performance is evaluated for the thermoformed structure and the effects of the thermoforming process are compared numerically, for the cases with and without the inclusion of process effects

Design and Development of a Multi-material, Cost-competitive, Lightweight Mid-size Sports Utility Vehicle’s Body-in-White

Vehicle light-weighting has allowed automotive original equipment manufacturers (OEMs) to improve fuel efficiency, incorporate value-adding features without a weight penalty, and extract better performance. The typical body-in-white (BiW) accounts for up to 40% of the total vehicle mass, making it the focus of light-weighting efforts through a) conceptual redesign b) design optimization using state-of-the-art computer-aided engineering (CAE) tools, and c) use of advanced high strength steels (AHSS), aluminum, magnesium, and/or fiber-reinforced plastic (FRP) composites. However, most of these light-weighting efforts have been focused on luxury/sports vehicles, with a relatively high price range and an average production of 100,000 units/year or less. With increasing sports utility vehicle (SUV) sales in North America, focus has shifted to developing lightweight designs for this segment. Thus, the U.S. Department of Energy’s (DOE) Vehicle Technologies Office has initiated a multi-year research and development program to enable cost-effective light-weighting of a mid-size SUV. The proposed designs shall enable weight reduction of a minimum of 160 lb. (~72.7 kg), with a maximum allowable cost increase of $5 for every pound of weight reduced. The proposed designs shall enable vehicle production rates of 200,000 units/year and will be aimed at retaining the joining/assembly line employed by the OEM. A systems approach has been utilized to develop a multi-material, light-weight redesign of the SUV BiW that meets or exceeds the baseline structural performance. This study delves into the development of design targets for the proposed redesign at the system, sub-assembly, and component levels. Furthermore, results from topology optimization studies on a design volume were assessed to understand the load paths under various loading conditions. Several multi-material concept designs were proposed based on the insights provided by the topology optimization study. Novel multi-material joining methodologies have been incorporated to enable maximum retention of the OEM’s joining and assembly process without significantly increasing cost. This paper presents the systems approach, and results from design studies undertaken to meet the program challenges

Nonlinear Model Predictive Control of UV-Induced Thick Composite Manufacturing Process

In this paper the nonlinear model predictive control (NMPC) of UV-induced curing of composite material for manufacturing of thick parts is proposed. The process involves layer-by-layer curing of thin composite laminates to form thick part. The model for NMPC switches when a new layer is added to the existing layer. The layer addition times are determined externally. The offline optimal control is used to determine the optimal time and temperature profile which will give uniform cure distribution of a thick composite material. Once the temperature trajectory and optimal time sequences are found, the NMPC is implemented for online control. The objective is to determine theoretical optimal behavior (assuming the process measurement is available) which will be used for online switching NMPC for tracking the reference temperature.Mechanical Engineerin

Effect of In-Situ Compaction and UV-Curing on the Performance of Glass Fiber-Reinforced Polymer Composite Cured Layer by Layer

In this paper, the effect of in-situ compaction and UV-induced curing on the performance of fiber-reinforced diglycidyl ether bisphenol A (DGEBA) based epoxy is studied for a layer-by-layer curing process. The optimum percentage of photo-initiator concentration and UV-intensity were obtained by conducting a different experiment for each of them. Fourier Transform Infrared (FTIR) spectroscopy method is used to determine the degree of cure. Then, short beam shear (SBS) test is conducted to measure the inter-laminar shear strength of the cured product under different compaction load. The UV intensity and Photo-initiator concentration were kept constant during the test. The result showed that thick composite parts fabricated with in-situ compaction and UV curing process have showed increased inter-laminar shear strength with increased compaction load up to a certain point. An increase in compaction beyond this point decreased the interlaminar-shear strength.Mechanical Engineerin

A Data-Driven Predictive Maintenance Framework for Injection Molding Process

Injection molding is the most common process to produce a wide range of complex plastic parts for many different applications, and a large number of machines and devices used in the plastics industry are associated with this process. Maintenance instructions and procedures used in the majority of injection molding plants currently are based on reactive and/or preventive strategies such as replacing failed components and/or performing regularly scheduled maintenance. However, such strategies are not cost-efficient and only partially effective in preventing machine downtime or producing scraps. The emergence of Industry 4.0 related technologies, such as cyber-physical systems, Internet of Things (IoT), cloud and edge computing, new sensors, and vision-based systems, brings new opportunities for the plastics industry to enhance their production and enterprise systems. Developing data-driven, predictive maintenance systems is one such opportunity that can help injection molding companies significantly reduce their maintenance cost while increasing their product quality and production efficiency. Accordingly, in this work, we introduce a generalized framework for implementation of predictive maintenance in injection molding process by integrating a variety of different data sources available in this process and taking the advantage of both cloud and edge computing. To demonstrate this framework, a case study on monitoring of the cooling system in injection molding process is presented. The results show the effectiveness of this approach in detecting cooling issues by monitoring other process data that are not directly correlated to the mold temperature. The comparison of the predicted mold temperature with the respective sensor value demonstrates an average error of 3.29 %, which can gradually be improved by accumulating more training data in the cloud-based system

Impacts of Adding Photovoltaic Solar System On-Board to Internal Combustion Engine Vehicles Towards Meeting 2025 Fuel Economy CAFE Standards

The challenge of meeting the Corporate Average Fuel Economy (CAFE) standards of 2025 has led to major developments in thetransportation sector, among which is the attempt to utilize clean energy sources. To date, use of solar energy as an auxiliary source ofon-board fuel has not been extensively investigated. This paper is the first study at undertaking a comprehensive analysis of using solarenergy on-board by means of photovoltaic (PV) technologies to enhance automotive fuel economies, extend driving ranges, reducegreenhouse gas (GHG) emissions, and ensure better economic value of internal combustion engine (ICE) -based vehicles to meet CAFEstandards though 2025. This paper details and compares various aspects of hybrid solar electric vehicles with conventional ICE vehicles.Different driving locations, vehicle sizes, various driving patterns and different cost scenarios are used in order to enhance the currentunderstanding of the applicability and effectiveness of using on-board PV modules in individual automobiles and ensure an accuraterepresentation of driving conditions in all U.S states at any time. These times and location-dependent results obtained over a year show anincrease in the combined mile per gallon (MPG) at noon in the range of 2.9-9.5% for a vehicle similar to a Tesla S, and a significantincrease in the range of 10.7-42.2% for lightweight and aerodynamic efficient vehicles. In addition, by adding on-board PVs to cover lessthan 50% of the projected horizontal surface area of a typical mid-size vehicle (e.g., Toyota Camry or Nissan Leaf), up to 50% of totaldaily miles traveled by an average U.S. person could be driven by solar energy. Also, the return on investment (ROI) of adding PVson-board with ICE vehicle over its lifetime shows only negative values when the price of gasoline remains below $4.0 per gallon and thevehicle is driven in low-solar energy area (e.g., Boston, MA). The same ROI is more than 250% if the vehicle is driven in high-solarenergy area (e.g., Arizona), even if the gasoline price remains low. For future price scenarios, this ROI is much higher - nearly 10 times theinvestment cost under some scenarios, with the assumption of an eventual decline in battery costs. With regard to environmental impacts,significant gasoline gallons savings (~500-3400) and CO2 emission reduction (~5.0 to 34.0 short tons) are achieved