Front Bumper Research Articles

Experimental Investigation of Automotive Vehicle Transient Aerodynamics with a Reduced-Scale Moving-Model Crosswind Facility

<div class="section abstract"><div class="htmlview paragraph">Automotive vehicles operate in complex, transient aerodynamic conditions that can potentially influence their operational efficiency, performance and safety. A moving-model facility combined with a wind-tunnel is an experimental methodology that can be utilized to model some of these transient aerodynamic conditions. This experimental methodology is an alternative to wind-tunnel experiments with additional crosswind generators or actively yawing models, and has the added benefit of modelling the correct relative motion between the vehicle and the ground/infrastructure. Experiments using a <i>VW Golf 7</i> were performed with a 1:10 scale model at the moving-model facility at DLR, Göttingen and a full-scale, operational vehicle at the BMW Ascheim side-wind facility. Successful functionality of the newly developed automotive-vehicle configuration of the moving-model facility - including the side wind-tunnel operation, rotating wheels in contact with the ground, and data-acquisition on-board the moving model - was achieved. Direct comparison of transient pressure at 24 locations across the front and rear bumpers and over the centerline of the vehicles show relatively good agreement between the two methodologies; establishing the moving-model facility as a viable reduced-scale methodology for investigating transient aerodynamics of automotive vehicles. Analysis of the time-resolved pressure measurements provides insight into the sensitivity of the surface pressure to transient crosswind; with indications that transient characteristics can only be captured with transient modelling of the crosswind-vehicle interaction.</div></div>

Complex Workpiece Positioning System With Nonrigid Registration Method for 6-DoFs Automatic Spray Painting Robot

To reduce the labor effort in hazardous environments like spray painting, an automatic car part spray painting machine has been set up. This article presents an intelligent location procedure for this machine. The location procedure assumes that the car part is placed with a tiny arbitrary pose, furthermore some kinds of parts under inspection undergoes through the deformation and thus it contains a nonrigid model. To tackle this problem, a workpiece positioning system works though multicamera is established first. Subsequently, a novel modified iterative closest point (ICP) algorithm is proposed which registers the nonrigid shape to the undeformed source shape in the training library. The modified ICP combines the ideas from traditional ICP and deformation estimation from bounded biharmonic weights. It solves a nonlinear cost function by using Levenberg–Marquardt algorithm. As a result, it estimates the transformation of the target point cloud with regards to the source point cloud. Additionally, it improves the accuracy of traditional ICP and increases its scope to nonrigid shapes. By employing these results in our location procedure, it can estimate the 6-DOF pose of the car part to be painted in addition to that it also estimates the deformation compared to the source cloud in the training library. This information is subsequently used to modify the guidance trajectory of the spray gun. In this article, a test case of front bumper is given, as it is commonly made of soft plastic materials and undergoes deformation under the influence of the external force. All the stated results support the efficacy of our algorithm.

Safety performance optimization of front bumper system based on pedestrian lower leg protection

Taking the front bumper system of a passenger car as the research object, a finite element model of pedestrian lower leg collision was first established, and the tibial acceleration at Y400 was found to be high in the performance analysis. Second, the sensitivity analysis was performed on the main parameters of the bumper system to determine the skin Thickness and foam density are the main influencing variables. Finally, a performance improvement scheme is proposed, and the lower leg tibia acceleration is reduced by 47.71% after the improvement, indicating that the scheme is conducive to lower leg protection.

Comparative Investigation for the Performance of Steel and Carbon Fiber Composite Front Bumper Crush-Can (FBCC) Structures in Quarter-Point Impact Crash Tests

As Light weighting is the top priority for the automotive industry today, the push for reducing overall vehicle weight will likely include the consideration of materials that have not previously been part of mainstream vehicle design and manufacturing, including carbon fiber composites. Therefore, the deformation characteristics and crush performance of carbon fiber reinforced polymer (CFRP) and steel front bumper crush-can (FBCC) assemblies in Quarter-point Impact Tests are investigated in this article. The experimental tests in this study were conducted using a sled-on-sled testing method. Force-time histories, kinematic data and videos for each test were recorded using several high-speed cameras (HSCs), accelerometers and a load cell wall. The collected data was filtered with SAEJ211 CFC 180 filter and sorted to ease the comparative analysis for the performance of the steel and CFRP bumper assemblies. A similar pattern was observed in the crashworthiness characteristics (i.e. force-time history, force-displacement, crash pulse and deformation patterns) of all steel and CFRP FBCC specimens. Typical failure modes of composite bumper assemblies, which were revealed by the high-speed videos were the failure of crush-can and failure of the bumper beam due to the generation of high stresses as it gets stretched due to its curvature after hitting the sled. On the contrary, local permanent deformation of the beam and crush-can was the predominant failure mode in steel FBCCs assemblies under quarter-point loading. Results obtained from the comparative investigation show that CFRP is a more efficient yet lighter material in regard to the absorption of the impact energy.

Interpretation of Fire Safety Distances of a Minivan Passenger Car by Burning Behaviors Analysis

In a car fire, thermal radiation poses a major threat to people and adjacent cars. Thus, estimations of fire safety distances are of great significance for the evacuation assignment and parking lot design. In the present full-scale experiment of a minivan car fire, the left cooling fan in the engine compartment was ignited as the origin of fire. The burn down of front bumper and windows markedly affected the fire intensity in engine and passenger compartment respectively. In the burning process, the peak heat release rate reached maximum value of 3.38 MW when gasoline leaked out. The flame model was assumed to be a superposition of several cuboids for the estimation of view factors of the fire. The average radiative fractions in the intense burning phases of engine and passenger compartments were first determined as 0.469 and 0.589, respectively, based on the burning behavior analysis. The resulting values allowed for the determination of thermal radiation in spatial positions and fire safety distances in the lateral side of the car for people and adjacent cars, which was an extension of previous researches of considering only the thermal radiation in certain positions. The calculation results of thermal radiation were in good agreement with the previous experimental data. The fire safety distances in the lateral direction of the car for people without protection and adjacent cars in this study, as examples, were about 7.3 m and 2.1 m respectively under threshold values of heat fluxes.

PENGARUH FRAKSI VOLUME PENGUAT 2, 2,5 DAN 3% SERAT BAMBU HAUR DAN FIBERGLASS TERHADAP KEKUATAN TARIK MATRIKS POLIESTER

Against the backdrop of the increasing need for quality composite materials and the development of increasingly advanced composite manufacturing technology in the machinery industry. The aim of this research is to develop composite materials with bamboo fiber reinforcement and glass fiber as an alternative to automotive raw materials to replace plastic. Preparation of composite specimens with each reinforcement with volume fractions of 2%, 2.5%, and 3% and specimens without reinforcement or 0% volume fraction as a comparison.
 The polymer material used is Yukalac 157-EX BQTN polyester as its matrix. With haur bamboo fiber and fiberglass as a reinforcement. Making specimens using the hand lay up method. Tests carried out are composite specimen tensile tests. Tensile testing was carried out using the ASTM D 638M-84 M-1 standard.
 Based on the test results, it was concluded that the effect of fiber volume fraction on the characteristics of composite samples for tensile tests. Composite strengthened by haur bamboo and fiberglass powder at 3% heavy volume fraction has the most ideal characteristics that have a tensile strength of 53.581 MPa, modulus of elasticity of 87.452 MPa and polymer composite material with a strength of haur bamboo and fiberglass powder with a length of 5 mm at 3% reinforcing volume fraction can be used as an alternative to automotive raw materials, namely replacing polyoxymethylene plastic materials for the front bumper.

Design and manufacture of automotive composite front bumper assemble component considering interfacial bond characteristics between over-molded chopped glass fiber polypropylene and continuous glass fiber polypropylene composite

This work presents the experimental and finite element analysis (FEA) study of the bond behavior of a continuous glass fiber-reinforced thermoplastic composite rod (3D-Tow)/over-molded long chopped glass fiber-reinforced thermoplastic (LFT) composite. To obtain the interfacial bond strength between the 3D-Tow and LFT of the composite, pull-out tests were performed according to over-molding conditions of the LFT material to investigate the bond-property changes with respect to the process parameters. From the experiment results, the traction–displacement behavior of the 3D-Tow/LFT interface was derived based on the cohesive zone model (CZM). The obtained bond properties were applied to a structural simulation, which accurately predicted the mechanical behavior of a prototype front bumper assemble component made of the 3D-Tow/LFT composite.

Analysis of frontal bumper beam of automobile vehicle by using carbon fiber composite material

The bumper is a structural member which is used to absorb the impact or sudden loads in the automobile vehicles, which are applied intentionally or unintentionally. The objective for the incorporation of the bumper is when the vehicle is suspended to sudden or impact loads by any collision, then it is used to absorb that impact energy and is helpful for the safety of the passengers as well as for the vehicle.In this present work, the displacement and stress analysis and design optimization of the automobile vehicle frontal bumper beam is achieved by designing eight different cross sections with the help of mechanical modeling based software Creo. The various cross-sections designed are (a) Open Hat section, (b) C section, (c) Rolled form section, (d) Open B section, (e) Close B section, (f) Hat close box section, (g) E section, (h) Rectangle section. The carbon fiber composite material is used for this purpose. To model these bumper beams, the profile used is flat with the curved angle. The designed sections are analyzed as per the national highway traffic safety administration, and federal motor vehicles safety standards regulations. The frontal perpendicular impact test is performed on the bumper beam at low-speed load with the help of finite element software HyperMesh. In the present work, the material used is carbon fiber composite.

Modelling and Simulating the Effect of Sunlight Heat on Front Bumper

In this speeding modern world, it became a necessity to have at least one car for every family. There often comes the time when the car has to be parked in an open area due to space or parking unavailability. During daytime, the sunlight heat causes the car’s exterior parts to get heated. Especially the summer heat in India is unbearable. The temperature rises too high that the stationery car’s exterior parts can reach the temperature of 90°C (Considering the car is stationery for over a period of time). The parts of the car that are exposed to sunlight heat are Hood, Front and rear bumper, Doors and Roof area. Out of all the exterior parts, Bumper is plastic and it is the most important when it comes to style and safety. In this research the effect of Sunlight heat on Front bumper is studied. The problems associated with sunlight heat on Front bumper are; the front bumper goes out of its original shape, disturbs the Clearance (Gaps) and fitting with surrounding parts, if the surrounding parts are too stiff the Front bumper itself undergoes high deformation and high internal stresses will be developed at the mating regions. In this research the FE modeling of Front bumper is done using ANSA software, the sunlight heat effect is simulated using ABAQUS solver. From the simulation results, there is 5.86mm deformation observed on Front bumper, and at the mating regions (The region where Front bumper is surrounded by other parts like Head lamp, Hood, Wheel arch) there is a displacement of 3.39mm (maximum clearance maintained at mating regions is 3mm). Several countermeasures were studied and the best way to avoid the deformation is adding Honey-comb ribs, stiffeners at the mating regions.

Functional optimization of hot-stamped components by local carburization

One of the major challenges in modern car body construction is the reduction of component weight while still maintaining passenger safety. In terms of these requirements, the substitution of conventional steel grades by ultra-high strength materials is the most promising approach. Hot stamping of these steels has developed to a state of the art process for manufacturing safety-relevant car body parts such as B-pillars or front bumpers. By locally adjusting the mechanical properties, for example, increasing the ductility, passive safety can be further improved. For this purpose, the hot stamping process is adapted in different ways. Varying from these established methods, tailored carburization is an alternative approach for manufacturing functional optimized components by combining hot stamping with prior local carburization. Within this work, the potential of local carburization is analyzed by a fundamental investigation of the influence of the process parameters on the mechanical properties as well as the transition zones between carburized and non-carburized areas. Besides the mechanical properties, the heat transfer between carburized sheets and tools is studied. The process suitability is validated by a demonstrator.

Additive manufacturing applied to injection moulding: technical and economic impact

PurposeThe purpose of this study is to compare the overall performance of the injection moulding process by using metallic inserts produced by both conventional technologies and selective laser melting (SLM).Design/methodology/approachA systematic methodology is proposed for prior evaluation of the effectiveness of conformal cooling channels to reduce cycle time and/or to reduce the scrap rate.FindingsThe mould was reengineered considering the SLM process and manufactured. Injection trials were carried out to validate expectations provided by injection simulations, which resulted on good quality parts and a significant decrease on cooling time, and, consequently, on the overall cycle time. The minimisation of scrap provided energy savings and time-to-market reduction.Research limitations/implicationsThe initial costs for AM tools still pose some doubts on decision-makers. The challenge of this study is to implement the methodology on a small-scale production and still ensure that benefits are achieved.Practical implicationsThe case study selected for this research work is based on a parking sensor housing, which is a plastic part assembled on the vehicle’s front and rear bumpers, therefore, with aesthetics concerns. The part produced with the conventional mould exhibits surface defects that, to be minimised (not eliminated), require a longer packing time to diminish the sink marks.Social implicationsThe economic impact of the use of SLM is relevant despite the low batch size for the case study presented. Energy savings are achieved due to scrap reduction and shorter cycle time.Originality/valueThe systematic methodology proposed for prior evaluation of the advantages of conformal cooling is possible to be applied both on small scale and high production series.

A Study for Detecting Flow Lines on The Aesthetic Plastic Parts During Design Phases as Using Material Flow Analysis Programs

In today’s competitive business environment the automotive industries aim to increase the usage of the plastic materials in automobile components in order to reduce weight of the vehicles. Although the plastic materials provide a considerable savings on vehicle weight, these materials have some problems to be solved. One of the difficult problems encountered in the production of plastics is the flow lines on plastics because of its unpredictable behavior. As a result, considered problem faced by automobile companies often spend plenty of time and money is an issue to resolve. In this study the source of plastic flow lines on automotive external aesthetical parts are investigated by using material flow analysis programs. According to conventional methodologies; weld lines, temperature differences, filling times, clamping forces, shrinkages parameters are examined deeply before tooling face especially to eliminate aesthetical problems. But in this case we observed an unordinary situation such as flow lines on front bumper visible surfaces after tooling phase and therefore we searched a new approach to simulate this flow lines on the material flow analysis program. Flow directions and flow velocity are comprehensively examined step by step during filling analysis. As a result of the analysis the geometric factors that affect the balance of flow and brings turbulence are detected. After the root cause analysis for plastic deformation the potential techniques are researched to find best solution. Analysis are repeated in the same conditions that are considered to be made for all geometric changes. The experiment results are comparatively analyzed and the solution approach that have the best flow balance is selected.

The Impact of the Application of Lean Tools for Improvement of Process in a Plastic Company: a case study

This article is the result of a work developed in plastic products manufacturing plant. The main objective of this project was the implementation of Lean tools in the two main products of this company, the wheel covers and the front bumpers, in order to obtain a reduction in the cycle times, an increased output in the production lines and a reduction in the complains associated to these products. The investigation methodology used was Action Research. This investigation began with the bibliographic review of Lean and the main Lean tools used in this organizational model such as 5S, Visual Management, SMED, Standard Work and OEE. The diagnose was initiated through a detailed description and analysis of the several processes associated with each product. For that, several parameters were analyzed (non-conformities, complains, delivery delays and calculating the OEE values) and the improvement opportunities were identified. For each identified aspect, improvements were proposed trough Lean tools and methodologies such as 5S, Visual Management, SMED and Standard Work. Some improvements also applied to the process had no relation to Lean tools and methodologies. The implementation of the suggested improvement proposals had quite positive impacts such as the 70% reduction of transportation times in the painting production line and the growth of the OEE index in 18% in the injection process, 16% in the painting production line of the Wheel Covers and 17% in the painting production line of the Front Bumpers.

A Study on Influence of Minivan Front-End Design and Impact Velocity on Pedestrian Thorax Kinematics and Injury Risk

Thoracic injuries occur frequently in minivan-to-pedestrian impact accidents and can cause substantial fatalities. The present research work investigates the human thoracic responses and injury risks in minivan-to-pedestrian impacts, when changing the minivan front-end design and the impact velocity, by using computational biomechanics model. We employed three typical types of minivan model of different front-end designs that are quite popular in Chinese market and considered four impact velocities (20, 30, 40, and 50 km/h). The contact time of car to thorax region (CTCTR), thorax impact velocity, chest deformation, and thoracic injury risks were extracted for the investigation. The results indicate that the predicted pedestrian kinematics, injury responses, and thoracic injury risks are strongly affected by the variation of the minivan front-end design and impact velocity. The pedestrian thoracic injury risks increase with the increasing vehicle impact velocity. It is also revealed that the application of the extra front bumper is beneficial for reducing the thoracic injury risk, and a relatively flatter minivan front-end design gives rise to a higher thoracic injury risk. This study is expected to be served as theoretical references for pedestrian protection design of minivans.

Behavior of Shear Thickening Fluid (STF) impregnated fabric composite rear wall under hypervelocity impact

On the contrary to previous researches on Shear Thickening Fluid (STF) impregnated fabric composites as a protection method against low to middle velocity impact such as stabbing or bulletproofing, the application of STF on space shields seems to be quite skeptical due to high-speed range of micro meteoroid and orbital debris (M/OD). However, the results of the eight types of fabric rear layers involving STF impregnated fabric of this study suggest that STF impregnated fabric can be a promising candidate for the improved rear wall of a space shield. After hypervelocity impact to the Al 6061-T6 frontal bumper, the all Heracron fabric rear wall was not fully penetrated against the hypervelocity fragments. However, a large hole was found in case of 2 mm Al 6061-T6 rear wall with the almost identical areal density and impact velocity. By replacing last 10 Heracron fabric layers from the rear side of the fabric rear wall to 6 layers of STF impregnated fabric, the trend in the number of undamaged layers was positively inversed. The study shows experimentally that the fabric rear wall of a space shielding system can be enhanced effectively by using STF impregnated layers.

A Study of Strength Property and Durability on Automotive Front Bumper Guard by Configuration

A Study of Strength Property and Durability on Automotive Front Bumper Guard by Configuration

76–81 GHz LTCC antenna for an automotive miniature radar frontend

AbstractFor a fully 360° detection around a vehicle, novel automotive radar system concepts consist of up to eight radar sensors. The existing sensor-mounting areas, such as front grill or bumper corners would no longer be sufficient. Therefore, additional mounting positions such as B-pillars and side skirts have to be considered, where the radar can observe the side area of the vehicle. However, these new mounting positions usually offer significantly less space, than the established mounting areas. The solution is, to build separate miniature radar frontends that can be placed all over the vehicle and are connected to one central signal processing and power supply unit. Investigations for a miniature radar frontend have been done, based on RF360 low loss non-shrinkage low-temperature cofired ceramic (LTCC) substrate. For the automotive radar band (76–81 GHz), an array antenna has been simulated, manufactured, and the radiation pattern has been measured. A first sensor with a miniature radar frontend based on an LTCC multilayer has been designed and manufactured.

Hypervelocity impact testing on stochastic and structured open porosity cast Al-Si cellular structures for space applications

A hypervelocity (6.7–7.0 km/s) impact testing campaign was conducted using Ø 2 mm, 95% Al projectiles onto A357 aluminium alloy stochastic foams with 4–5 mm typical pore dimensions, or alternatively diamond cubic periodic structures of cast AlSi12 with a 6 mm lattice parameter, in order to assess their performance as shielding material against orbital impacts. Either 0.15 mm Al foil or multi-layer insulation (MLI) was used as a front bumper material. It was found that the periodic structures failed to retain the impact debris for any incident angle of impact between 0° and 12°, at least in part due to ricochets and/or spalled material finding its way through open straight channels within the periodic structure. A porous material architecture traversed by no open, straight path is thus required for proper impact protection. Stochastic foams satisfy this criterion and indeed were found to stop the debris. Depending on bumper configuration, stochastic foams gave comparable performance to that of simple Whipple shield designs at 1.3–1.9 × the areal weight. We suggest that a finer pore structure with respect to the projectile diameter should yield a higher impact absorption per areal weight. As an auxiliary result, it was found that MLI as a front bumper was less efficient in fragmenting the projectile compared to Al foil of similar areal weight. In conclusion, open porosity stochastic foams are a promising material as sandwich panel cores for space applications, as they may reduce the need for a dedicated shield, so long as the small debris produced by the impact can be isolated from the satellite systems.

One Day the Emails Will End.

One Day the Emails Will End.

Mechanical Properties and Microstructure of High-Strength Steel Controlled by Hot Stamping Process

A novel design and manufacturing method, dubbed “precast,” of the cooling system and tools for a hot forming process was proposed in this paper. The integrated structures of the punch and blank holder were determined by analyzing the bending and reverse-bending deformation of the forming parts. The desired crashworthiness performance of an automotive front bumper constructed with this process was obtained by a tailored phase transformation, which generated martensite-bainite in the middle and full martensite transformation in the corner areas. Varying cooling effects in the formed parts caused the highest temperature to be located in the bottom and the lowest on the end of the formed parts. Moreover, the microstructural distributions demonstrated that the bottom possessed a relatively lower content of martensite, while, conversely, the end possessed a higher content. This was precisely the most desired phase distributions for the hot formed parts. For the six-process cycle stamping, the temperatures reached a stable status after an initial rapid increase in the first three process cycles. The microstructural results verified the feasibility of the hot forming tools under multiprocess cycles.