Hood Design Research Articles

Design of Outer Hood Panel of Local Compact Suv to Achieve Better Pedestrian Safety using Finite Element Modeling

Traffic accidents are terrible scourge that occur in many countries, specially for developing countries where transportation affairs like tangled yarn. Besides functioning as an engine compartment cover, the hood of modern compact SUV can also help to manage the impact energy of a pedestrian’s head in a vehicle-pedestrian impact. This paper presents a compact SUV outer hood design that has a potential to improve hood’s ability and also to absorb the impact energy of a pedestrian’s head. The developed method for the design of a hood configuration aims to provide a robust design and homogeneous of Head Injury Criterion (HIC) for impact position at WAD 1000 and three different thicknesses (1.25 mm, 1.35 mm & 1.50 mm) of outer hood panel of local compact SUV, taking into consideration the limited space available for deformation. The non-linear Finite Element Analysis (FEA) of ANSYS software (Expilit Dynamics) was used in this research to simulate the testing procedurs of head impact for child pedestrian. The results show that a minimum of deformation space meet the requirement for HIC value which required to obtain robust and homogeneous head impact performance. Hood thickness and materials were identified as the main factors to influence the stress and HIC value of the hood. By comparing all models, magnesium alloy (non linear) (1.25 mm) was selected as the best models which greatly improved up to 29.46% for the pedestrian safety.

Analysis and use of SIMP method in optimization of a car hood design

The article shows the relevance of creating digital twins and conducting topological and topographic optimizations as part of improving the physical and mechanical properties of car parts using the example of a car hood. A description of the existing optimization methods is given and the principle of the SIMP method is described. The results of optimizing the design of the hood of the car using this method are presented. We demonstrate that using modern approaches to modelling and optimization of automobile parts makes it possible to achieve targets in the design and redesign, to achieve sufficient structural strength while maintaining or reducing the mass of the original structure. It is shown that modelling allows providing an array of information on the optimized part as soon as possible, as well as reducing the consumption of materials used to create it.

Simulations of dust dynamics around a cone hood in updraft conditions

A cone hood is an efficient device for capturing dust releases generated by a variety of process equipment. For stationary airflow conditions, a circular cone hood with a round flange is the most efficient design. The goal of this article is to determine the effect that inflow velocity, suction velocity, and terminal settling velocity of dust particles have on the aspiration coefficient in combination with hood length and inclination angle. No studies have yet addressed the efficiency of an exhaust hood facing an updraft flow of air with suspended dust particles. To simulate the moving fluid, we used the discrete vortices method accounting for flow separation at sharp edges of the cone hood. A custom test bench was built to validate the velocity field distribution around the exhaust hood. To evaluate capture efficiency, we determined the aspiration coefficient using plotted limiting trajectories of dust particles by solving equations of particle dynamics numerically in view of gravity and streamlining airflow patterns. In order to validate our estimate of the aspiration coefficient, we compared our findings with regularities identified by earlier researchers for a simpler problem of dust-air mixture approaching a circular exhaust opening. The following conditions were considered: the ratio of updraft velocity to the exhaust hood suction velocity varying between 0.01 and 0.5; the ratio of dust particle terminal velocity to the suction velocity varying between 0.000625 and 0.2; flange angle varying between 0° and 90°; and the ratio of flange length to the exhaust opening radius varying between 1 and 4. Using regularities discovered by us, exhaust hood designs can be tailored to a variety of application conditions in terms of dust release capture efficiency.

2D-PIV measurement of range hood-driven flow in a domestic kitchen

High-performance range hoods can quickly exhaust cooking smoke and fumes outdoors. Quantifying the detailed information that range hood-driven flow provides can be an essential prerequisite to optimize the hood's performance. Direct measuring instruments cannot easily determine the velocity due to large velocity gradients and high temperatures. Particle image velocimetry (PIV) is a non-intrusive velocimeter-based method with high spatial resolution and in a global domain. Thus, we applied large-scale 2D-PIV and measured the range hood-driven flow in three sections under isothermal and heating conditions. This study systematically investigated the influence of the exhaust flow rate and mounting height on the range hood-driven flow. The measurement results under isothermal conditions show the actual airflow driven by a range hood cannot be characterized as a simple exhaust and have self-similarity for different exhaust airflow rates. The results also indicate that the mounting height only slightly impacts the velocity boundary conditions of the range hood exhaust surface. The results under the heating conditions clearly reveal that the time-averaged spill length is larger than the average value of the dynamic spill length. This phenomenon indicates that the relationship between time-averaged velocity fields and spill length is not a simple linear scaling relationship. The unsteady flow in the kitchen should be considered to determine the true capture efficiency. Moreover, uncertainty analysis ensures that the benchmark flow data for the follow-up kitchen environment and range hood design simulations.

Introducing composite lattice core sandwich structure as an alternative proposal for engine hood

Pedestrian protection capability is critical for lightweight design of automotive engine hood. Here, a novel and lightweight composite sandwich hood including two fiber reinforced composite panels and a lattice core was proposed and the corresponding pedestrian protection performance was evaluated via Head Injury Criterion (HIC). The novel double-curvature composite sandwich hood with a pyramidal lattice core was designed based on a commercialized product with a weight reduction by 25%, and fabricated using interlocking approach. A homogenized constitutive model was developed for the pyramidal lattice core and utilized in the following headform-to-hood impact simulations with LS-DYNA. The stiffer sandwich hood revealed better pedestrian safety performance compared with the corresponding baseline hood without lattice core where secondary collision happened. Also, effects of geometrical variables, material selection and core types were discussed. The variation of panel thickness played a more important role in the average HIC values compared with that of core geometries. Among various material selections, hoods designed with carbon fiber reinforced composite (CFRC) panels and a flax fiber reinforced composite (FFRC) lattice core achieved the minimum head injury. Additionally, lattice core outperformed traditional honeycomb and foam in sandwich hood design. The present study demonstrates the feasibility of employing lattice materials in lightweight design of hood and other car body coverage.

Experimental and numerical flow analysis and design optimization of a fume hood using the CFD method

The experimental and numerical analyses of the standard fume hood features in order to determine the nature of the flow phenomena within the working chamber are presented and studied in the paper. The experiments were carried out for three characteristic heights of the vertical sliding sash, i.e., the lowest (closed), working and the highest (fully opened) heights. The air flow parameters such as: mass flow rate, local distribution of velocity at the exhaust plenum and inlet and pressure drop were measured and analyzed. Assuming isothermal, incompressible and turbulence flow of the air treated as ideal gas, the numerical model based on the continuity and momentum equations was proposed and solved using the Finite Volume Method (FVM). The numerical model was validated against the obtained experimental results. The goal of the numerical simulations was to investigate the flow structure and condition inside the fume hood for different heights of a vertical sliding sash. The obtained numerical results indicated the intensified air recirculation zones within the fume hood chamber and showed the complicated nature of the flow. The conclusions and fume hood design guidelines aimed at reducing the size of the recirculation zones and thus reducing the noise and power needed to drive the exhaust fan were determined. On the basis of the performed calculations four modifications of the fume hood design were proposed and numerically analyzed. Finally, the reduction of the recirculation zones therefore a decrease of pressure drop by 30.5% was achieved.

A Design to Environment Modelling Approach based on Time Variation Networks

Multidisciplinary collaboration from different domains and expertises became a necessity to address the environmental aspects in innovative design decisions and development. Designing to Environment involves overlap of information used and created by the diversity of product design expertises. It remains difficult for product designers and environmental experts to interrelate their respective parameters. This prevents product designers to converge toward environmentally aware design choices. This research therefore investigates the use of time Parameter Network Models to follow the emergence of environmental parameters linkage with product designer expertises’ parameters. An industrial cooker hood design process case study explores the co-creation of local environmentally-aware knowledge between product designers based on this parameter linkage. Interesting opportunities are identified to furthermore translate parameter linkage in transformation rules between entities and parameters models. After instantiation such rules would allow dynamic and flexible information exchanges between product designers’ and environmental expertises’ activities along the design process.

The Topology Optimization Design Research for Aluminum Inner Panel of Automobile Engine Hood

This article discusses the topology optimization methods for automobile engine hood design. The aluminum inner panel of engine hood and mucilage glue regions are set as design areas, and the static performances of engine hood included modal frequency, lateral stiffness, torsional stiffness and indentation stiffness are set as the optimization objectives. The topology optimization results about different objective functions are contrasted for analysis. And based on the reasonable topology optimization result, a suited automobile engine hood designs are raised to further study. Finally, an automobile engine hood that good at all of static performances is designed, and a favorable topology optimization method is put forward for discussion.

Sampling method for the determination of methane emissions from landfill surfaces.

The first aim of this work is the definition and the study of a suitable sampling method for the measurement of landfill gas (LFG) emissions from landfill surfaces, since, up to now, there are no codified nor universally accepted sampling methods for this specific task. The studied sampling method is based on the use of a static hood. The research work involves a preliminary theoretical study for the hood design, experimental tests for the definition of the optimal sampling procedures, and simulations of the hood fluid-dynamics for the system validation. The second aim of this study is the investigation of the correlations between LFG emissions and meteorological conditions, whose identification would be very useful in terms of effective landfill management and pollution control. This involved a wide literature study for the selection of those parameters that seem to have an influence on LFG emission, and the collection of a great number of experimental data on a target site, which led to the conclusion that atmospheric pressure and soil humidity are the parameters that mostly affect LFG emissions.

レンジフードのデザイン支援システムの構築 : システムキッチンとレンジフードのデザインに関する研究(2)

レンジフードのデザイン支援システムの構築 : システムキッチンとレンジフードのデザインに関する研究(2)

Improving pedestrian safety via the optimization of composite hood structures for automobiles based on the equivalent static load method

In this study, design optimization of a composite hood for automobiles was carried out to mitigate the impact of pedestrian head injuries based on finite element analysis. Reduced vehicle, headform impactor and single hood models were established to obtain optimal composite hood designs. The carbon fiber reinforced composite (CFRP) and the hybrid Glass fiber reinforced composite (CFRP/GFRP) laminates were selected as composite material candidates. Both stacking angle sequence and topometry of the composite hood were optimized based on the equivalent static load method. After the optimization, the head injury criterion (HIC), deflection and weight were measured to evaluate the performance of the composite hood. The developed CFRP and hybrid CFRP/GFRP type hoods with optimized final design exhibited the improved impact performance and significant weight reduction while satisfying bending and torsion deflection requirements compared to those of conventional steel and aluminum hoods.

Weighting of Natural Fibre Criteria for Fibre Metal Laminate Using Entropy Method for Car Front Hood Utilization

Material selection is one of the crucial stages in design and development process which depend on various physical, mechanical and manufacturing properties. To increase the success probability of the product, the designer needs to decide the suitable material. Therefore, to increase the reliability of the product, entropy method could be applied to determine the importance of criteria for the material used. Entropy method is a highly reliable and can be adjusted to information measurement to determine weighting criteria in decision making environment. Weighting criteria of material play a very significant role in the ranking results of the material selection. Therefore, the aim of this study is to utilise entropy method to rank the main criteria of the natural fibre used in fibre metal laminate panel for car front hood design. It is important to define the main criteria of materials during the material selection process to prevent any mechanical failure and to control the raw material cost. Most of the fibre metal laminate in the market utilise synthetic fibre, while natural fibre is rarely explored. Entropy method was applied to determine the main criteria weighting of natural fibre using five criteria. The result showed the highest rank to the lowest rank for the main criteria is density, stiffness, water absorption, cost and finally availability.

Application of Analytic Hierarchy Process (AHP) in the analysis of the fuel efficiency in the automobile industry with the utilization of Natural Fiber Polymer Composites (NFPC)

A systematic method of material analysis aiming for fuel efficiency improvement with the utilization of natural fiber reinforced polymer matrix composites in the automobile industry is proposed. A multi-factor based decision criteria with Analytical Hierarchy Process (AHP) was used and executed through MATLAB to achieve improved fuel efficiency through the weight reduction of vehicular components by effective comparison between two engine hood designs. The reduction was simulated by utilizing natural fiber polymer composites with thermoplastic polypropylene (PP) as the matrix polymer and benchmarked against a synthetic based composite component. Results showed that PP with 35% of flax fiber loading achieved a 0.4% improvement in fuel efficiency, and it was the highest among the 27 candidate fibers.

Life cycle assessment-based selection of a sustainable lightweight automotive engine hood design

This study presents a life cycle assessment (LCA)-based sustainable and lightweight automotive engine hood design and compares the life cycle energy consumption and potential environmental impacts of a steel (baseline) automotive engine hood with three types of lightweight design: advanced high strength steel (AHSS), aluminum, and carbon fiber. A “cradle-to-grave” LCA including the production, use, and end-of-life stages is conducted in accordance with the ISO 14040/14044 standards. Onsite data collected by Chinese automotive companies in 2015 are used in the assessment. The Cumulative Energy Demand v1.09 method is applied to evaluate cumulative energy demand (CED), and the International Panel on Climate Change 2013 100a method is used to estimate global warming potential (GWP 100a). Among the different lightweight designs for the engine hood, the aluminum design is the most sustainable and has the lowest CED and GWP (100a) from a life cycle perspective, which is based on a lifetime driving distance of approximately 150,000 km. In addition, the AHSS design is also sustainable and lightweight. The carbon fiber design results in higher CED and GWP (100a) values than the steel (baseline) design during the life cycle but results in the largest CED and GWP (100a) savings through waste material recycling. The AHSS design exhibits the best break-even distance based on CED and GWP (100a) within 150,000 km. Sensitivity analysis results show that the lifetime driving distance and material recycling rate have the largest impacts on the overall CEDs and GWPs of the three lightweight designs.

REDESIGN OF OUTER HOOD PANEL OF ESEMKA R2 CAR TO IMPROVE PEDESTRIAN PROTECTION USING FINITE ELEMENT MODELING

Traffic accidents are terrible scourge that occur in many countries, specially for developing countries where transportation affairs like tangled yarn. Besides functioning as an engine compartment cover, the hood of modern compact SUV can also help to manage the impact energy of a pedestrian’s head in a vehicle-pedestrian impact. This paper presents outer hood design of Esemka R2 that has a potential to improve hood’s ability and also to absorb the impact energy of a pedestrian’s head. The developed method for the design of an outer hood configuration aims to provide a robust design and homogeneous of Head Injury Criterion (HIC) for impact position at WAD 1000 and three different thicknesses (1.25 mm, 1.35 mm & 1.50 mm) of outer hood panel of Esemka R2 compact SUV, taking into consideration the limited space available for deformation. The non-linear Finite Element Analysis (FEA) software (Explicit Dynamics) was used in this research to simulate the testing procedurs of head impact for child pedestrian. The results show that the average of comparison dimensional of outer hood panel of Esemka R2 was 4.89 mm. The minimum of deformation space meet the requirement for HIC value which required obtaining robust and homogeneous head impact performance. Outer hood thickness and materials were identified as the factors to influence the stress and HIC value of the hood. By comparing all outer hood panels, aluminium alloy as the best selected material which has the lowest value is 32.78% for the pedestrian protection.

Use of CFD for static sampling hood design: An example for methane flux assessment on landfill surfaces

The work focuses on the principles for the design of a specific static hood and on the definition of an optimal sampling procedure for the assessment of landfill gas (LFG) surface emissions. This is carried out by means of computational fluid dynamics (CFD) simulations to investigate the fluid dynamics conditions of the hood. The study proves that understanding the fluid dynamic conditions is fundamental in order to understand the sampling results and correctly interpret the measured concentration values by relating them to a suitable LFG emission model, and therefore to estimate emission rates. For this reason, CFD is a useful tool for the design and evaluation of sampling systems, among others, to verify the fundamental hypotheses on which the mass balance for the sampling hood is defined. The procedure here discussed, which is specific for the case of the investigated landfill, can be generalized to be applied also to different scenarios, where hood sampling is involved.

Effects of work practices and upper body movements on the performance of a laboratory fume hood

A hood user's work practices and upper body movements can adversely affect the performance of a laboratory fume hood. To quantify the possible effects, hood performance was measured while simulating typical user activities scenarios. The tested variables were two sash opening heights, two hood clutter settings, two thermal loads, and three hand–arm–trunk motions, totaling 24 (2 × 2 × 2 × 3) different test conditions. Hood face velocity was maintained at 0.5 m/s for all tests, using a fan speed controller. For each test condition, the hood's performance was evaluated using the ASHRAE 110-1995 tracer gas test method. Duplicate measurements were made for each condition, so that a total of 48 tests were conducted, in random order. Three-way ANOVA was performed to find significant effects of work practices and upper body movements on breathing concentrations. The degree of sash opening was the most significant factor affecting hood performance, followed by hand–arm–trunk motions and thermal load. The effect of hood clutter was not statistically significant, but the interaction effect with other factors was. The highest breathing concentration value occurred during the test with the sash fully open, arms-down posture, thermal load present, and hood clutter present. These conditions created complex airflow patterns inside the hood that resulted in leakage into the breathing zone. Although the test conditions were limited, the results of this study suggest that good work practices in combination with good hood design and adequate face velocity can significantly reduce worker exposure. Reducing sash height while working in front of a laboratory fume hood is vital to reducing potential exposure to the air contaminant generated inside the hood.

A Numerical Investigation of a Novel Hood Design for Pedestrian Protection

Currently the use of new materials is becoming even more prevalent in vehicle industry for the lightweight design purpose. The design of engine hood is very important for pedestrian’s safety during a vehicle-pedestrian accident. In order to improve the pedestrian protection performance of the new material engine hood, the radial stiffening rib structure and trapezium sandwich structure engine hoods were proposed in this paper. And an energy-absorbing structure has been designed on the strengthening hinge plate to reduce the pedestrian head injury further more. The simulation results indicate that with new structures, the new material engine hoods have more uniform rigidity and better energy absorbing ability, which would effectively reduce the engine hood intrusion and pedestrian head injuries.

A case study for the effectiveness of solar-powered attic ventilation fans

The market for solar-powered attic ventilation fans (SPAVFs) is rapidly expanding. Many homeowners are increasingly turning to alternative technologies to reduce energy use and increase comfort in their homes. However, there is very little research data available on SPAVFs, and a significant observation of this research is that no industry standards currently exist that attempt to identify how the performance of the technology can be measured and verified to perform as advertised. The main purpose of this study is to measure the effects of a SPAVF on reducing high attic temperatures. To verify the effectiveness of a SPAVF, a case study is presented using data collected from Boone, NC, USA. In addition, this paper introduces a new prototype SPAVF hood design and describes the results of the airflow analysis of the prototype, which indicated that the prototype has the potential to offer increased attic ventilation at a time when it is needed most.

Evaluation of Engineering Controls for the Mixing Of Flavorings Containing Diacetyl and other Volatile Ingredients

Exposures to diacetyl, a primary ingredient of butter flavoring, have been shown to cause respiratory disease among workers who mix flavorings. This study focused on evaluating ventilation controls designed to reduce emissions from the flavor mixing tanks, the major source of diacetyl in the plants. Five exhaust hood configurations were evaluated in the laboratory: standard hinged lid-opened, standard hinged lid-closed, hinged lid-slotted, dome with 38-mm gap, and dome with 114-mm gap. Tracer gas tests were performed to evaluate quantitative capture efficiency for each hood. A perforated copper coil was used to simulate an area source within the 1.2-meter diameter mixing tank. Capture efficiencies were measured at four hood exhaust flow rates (2.83, 5.66, 11.3, and 17.0 cubic meters per min) and three cross draft velocities (0, 30, and 60 meters per min). All hoods evaluated performed well with capture efficiencies above 90% for most combinations of exhaust volume and cross drafts. The standard hinged lid was the least expensive to manufacture and had the best average capture efficiency (over 99%) in the closed configuration for all exhaust flow rates and cross drafts. The hinged lid-slotted hood had some of the lowest capture efficiencies at the low exhaust flow rates compared to the other hood designs. The standard hinged lid performed well, even in the open position, and it provided a flexible approach to controlling emissions from mixing tanks. The dome hood gave results comparable to the standard hinged lid but it is more expensive to manufacture. The results of the study indicate that emissions from mixing tanks used in the production of flavorings can be controlled using simple inexpensive exhaust hoods.