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Brazilian automotive market has been growing faster than ever. In order to react properly to market increasing demand in terms of volume and diversity, production systems have to be carefully designed. Traditional manufacturing tends to react to demand increase by outsourcing or investing in new equipments or facilities. Lean thinking suggests that by reducing waste along the value stream it is possible to increase flexibility and freed resources to reduce the investment level required to cope customer’s needs. This paper presents two cases of a system redesign based on the lean manufacturing principles to support the demand.

Digital factory is a concept that offers a collaborative approach to enhance product and production engineering processes through simulation. Products, processes and resources are modeled to be used to develop and test the product conception and manufacturing processes, before their use in the real factory. The purpose of this paper is to present the steps to identify the Critical Success Factors (CSF) priorities in a digital factory project implementation in a Brazilian company and how the Delphi and AHP Methods are aiding to identify these CSF priorities.

Various studies have shown that the level of wind noise experienced inside cars on the road in unsteady conditions can be substantially different from that measured in wind tunnel tests conducted using a low turbulence facility. In this paper a simple geometric body representing the cabin of a passenger car has been used to investigate the effects of free stream turbulence, (FST), on the A-pillar vortex flowfield and the side glass pressure distribution. Beneath the A-pillar vortex, both mean and dynamic pressures are increased by FST. The unsteady pressure can be associated with wind noise and the flow visualization shows the peak unsteadiness is related to the separation of the secondary vortex.

One challenge that the space, aeronautical and automotive industries are facing today is the fast growing number of vehicles versus the slowly growing number of useful orbits, routes, and speedways. Furthermore, the adoption of “free-flight”, “speed-drive”, etc. policies in the near future will only aggravate it. All these factors increase the risk of collisions and the frequency of deviation maneuvers to avoid them. But they also create the opportunity to devise policies to mitigate such problems, including algorithms to propagate the uncertainties in vehicle motions and to predict the risk of their collisions. This work discusses the development and simulation of an algorithm for the propagation of navigation uncertainties in the trajectory of aerospace vehicles, to minimize the risk of collisions. The scenario of Satellites Formation Flying shall be used for the simulations, with focus on the prediction of the collision probability.

A new spot joining technology relying on a consumable joining bit has been developed and evaluated on dual phase (DP) 980 steel and a dissimilar combination of aluminum alloy 5754-O and DP 980. This new process, called friction bit joining (FBJ), uses a consumable bit to create a solid-state joint in sheet materials by the action of cutting and frictional bonding. A series of experiments were done in which different welding parameters were employed and lap shear tension testing was carried out to evaluate performance. The best lap shear values averaged 6.5 kN.

When a gap exists in a resistance spot welded (RSW) joint, the lack of intimate contact between the members at the faying interface can have a significant influence on sheet steel spot weldability, especially for advanced high strength steels. Several test joints simulating gap conditions observed in typical auto body structures have been designed for study of the effect of gap magnitude on the resistance spot weldability of such AHSS as DP980, DP780 and DP600. Tests show that an existing gap reduces the confinement of the molten zone during the welding process, increasing the probability of expulsion and therefore decreasing the current range. Increasing the electrode force helps reduce the gap influence and broadens the current range. Employing a longer weld time also has a beneficial effect when used in combination with an appropriate electrode force.

Polymer-metal hybrid structures frequently require joints due to limitations associated with component size, fabrication capabilities and physic-chemical material incompatibilities. The FricRiveting technique is a new alternative spot joining process developed to fill this gap. In the process a cylindrical metallic rivet is used to join one or more thermoplastic-metal components by means of plasticizing and deforming the tip of the rotating rivet through frictional heating (average temperatures within 300-500 °C). As an illustration of the process, sound joints on polyetherimide/aluminum 2024-T351 with elevated mechanical strength (up to 93% of the rivet strength) were successfully produced within short joining cycles and requiring minimal preparation of joining partners.

Static and dynamic strength tests were performed on spot welded specimens made of dual-phase (DP) 780 and mild steels (DQSK). Lap-shear (LS) and cross-tension (CT) as well as a new mixed mode specimen were studied using MTS hydraulic universal testing machine for static tests and drop weight tower for dynamic tests. Three weld nugget sizes were made for each steel and CT and LS. DP780 with one weld size was also tested in mixed mode. Load and displacement as functions of time and fracture mode of the spot welds were recorded. Representative data are reported in this paper.

Spot friction welding shows advantages over resistance spot welding for joining light alloys for automotive applications. In this research, fatigue behaviors of spot friction welded joints in lap shear specimens of AM-60 magnesium alloy and AA 5754 aluminum alloy were investigated. Static and fatigue tests were conducted with Mg-Mg, Al-Al and Al-Mg specimens. Fatigue S-N curves were obtained for all these specimens using load-controlled fatigue tests. Finite element analysis was conducted to investigate the stress distribution and the location of maximum stresses in spot friction welded joints in Mg-Mg specimens.

It is becoming common in recent years to take measures on vehicle interior noise by balancing other performances or by using acoustic materials that are advantageous in terms of weight and cost. However, acoustic materials for vehicles are mainly for reduction of high-frequency noise in the vehicle interior, and are not realistic measures for mid-frequency noise including road noise where reasonable thickness is needed. In this study, therefore, we identified the condition to reduce mid-frequency sound by focusing on the mechanism to reduce particle velocity as the sound absorption principle of acoustic materials and by utilizing acoustic materials in thin sheets used as a measure on high-frequency sound. We further derived the specific structure to realize this condition in order to reduce road noise.

A single transducer wedge-reed ultrasonic welder has been used to make welds, in the non-age hardening aluminum alloy AA5754. A range of thickness combinations, varying from 1.2 mm to 2.5 mm, have been ultrasonically welded. A matrix of process parameters (input energy, impedance matching setting, tip clamp pressure and power) have been used to achieve high strength joints. Samples were welded in standard configuration for a tensile lap-shear test, which has been used to determine failure strength and type of failure. Optical microscopy has been used to reveal the bonding mechanisms. Variations in strength and failure mode have been related to changing process parameters and material thickness. It has been observed that stacking sequence has little effect on overall strength. Optimization of process parameters rather than the stack-up sequence has been shown to give the largest gains in joint strength.

Riveting is a well established technology in the manufacturing of aeronautical structures as well as in the automotive industries. Despite its simplicity, the rivet presents a local stiffness that is not easy to properly model within a large finite element analysis. However, precision in the local stiffness evaluation is essential to perform any structural analysis when several rivet are applied in a joint structure. The result is that any rivet requires a local mesh refinement or, and this is the most common case, a drastic simplification of its structural modelling characteristics. In the present paper the structural behavior of a riveted lap joint connection was investigated experimentally and numerically using a new rivet finite element. The Rivet Element, based on a closed-form solution of a theoretical model of the rivet joint, is able to precisely evaluate, in FE analysis, both local and overall stiffness of riveted joints with a very low contribution of dofs.

Autonomous guided vehicles, called AGVs, are important components of factory automation and manufacture system integration that requires both technical and management skills. In this paper, an AGV prototype equipped with IR detectors and IR range sensors is programming to follow a route line on the floor and avoid some obstacles on the way. The motion of the experimental AGV is promote by two DC motor with build-in gearbox, working with simultaneous PWM control in closed-loop operation. This AGV is designed to operate in environments such as offices and shop floor, in order to carry light loads on flat surfaces and ramps with positive and negative inclination. Simulations tests with ADAMS® are compared with some experimental results in order to validate the model and the prototype approaches.

Environmental and strategic considerations have driven the research and development on the use of alternative fuels in internal combustion engines. Natural gas has recently become available to final users in the Brazilian market and is being used in flex fuel engines. Besides the economic aspects, natural gas is an important model fuel whose understanding enables the study of more complex fuel mixtures. In the search for engineering tools to improve internal combustion engines design and optimization, the present work is focused on the development of a two-dimensional numerical model to simulate a port-injected natural gas internal combustion engine. Here, attention is directed to the development of the model as well as the physical and chemical phenomena associated to the fluid flow, combustion and heat transfer processes that take place inside the cylinder.

The rapidly increasing number of aircraft passengers requires improved techniques for aircraft manufacturers to provide high internal comfort for passengers and the crew. In this paper, the internal acoustic comfort was evaluated using binaural recordings inside three aircrafts of different sizes during regular flights. The parameters of sharpness, tonality and loudness, which are expected to be correlated with perceived sound quality, were calculated. The results of listening tests performed with or without loudness equalization were obtained applying the paired comparison technique. These results will be discussed in detail in this paper.

The purpose of this work is Fault Detection and Diagnosis (FDD) on a Knock Sensor because some of the modern petrol engines operate on the efficient four-stroke cycle, where each cylinder of the engine contains an intake and exhaust poppet valve that is operated at the appropriate time. The ECM (Engine Control Module) uses the Knock Sensor signal to control timing. The Knock Sensor detects engine knock and sends voltage signal to the ECM. These signals can be sufficient to detect abnormal combustion, like ‘spark knock’ and ‘surface ignition’. Engine knock occurs within a specified range. The Knock Sensor, located in the engine block, cylinder head, or intake manifold is tuned to detect that frequency, which motivates the use of signal models for detection. But this sensor is a wide-band accelerometer of the piezoelectric type too. Analogy with a general seismic mass system is possible since it is a general damped second order vibrating system which is forced into oscillatory motion.

Automotive stationary noise and vibration signals are normally analyzed using Fourier methods. However, many noise and vibration signals are non-stationary (transient or time-varying). In those situations, the time characteristics of the signals can be lost using standard Fourier methods. Lately, time-frequency (TF) analysis methods have become more popular and are applied in many different areas of NVH (Noise, Vibration, and Harshness) in order to preserve the time-frequency information. The objective of this paper is to present some of the different time-frequency analysis tools, such as the Short Time Fourier transform (spectrogram), the Gabor Transform, the Wavelet transforms (scalograms), and the Wigner-Ville Distribution. Examples of application of these techniques to automotive non-stationary noise and vibration signals are presented.

For the current brazilian market, the available sportive vehicles are mainly a slight modified version from a current model, usually only with appearance items. A good definition for a sportive vehicle should be something between a family vehicle and race car. A race car focus only in performance, obviously without any compromise for passenger comfort and a family vehicle is orientated for passenger comfort and safe behavior, for driver only or full load condition. One thought for a sport vehicle is a powerful engine, which should translate in greater acceleration, top speed and faster speed recovery. Besides the engine, other areas should support the increased torque and horsepower, resulting in improved lateral / longitudinal grip and faster steering response. Based on a production medium hatchback, several systems were improved in order to achieve a new exciting product, aiming a pure sportive behavior.

This paper investigates the application of thick film hybrid circuit technology on ceramic substrate in comparison to the main stream substrate FR-4 (Flame Retardant 4) for PCB implementation. The study is based on computer models for these very substrates in order to simulate the propagation of heat through convection and conduction within the material boundaries. In order to simulate electronic components surface mounted, different heat sources are randomly arranged on physical contact to the surface of the material under investigation. The results emphasize and discern the usage of both substrates and its most suitable environment verifying the application towards vehicular integration. Future study may include experimental analysis for simulated data verification and validation of thick film hybrid circuit technology for the automotive industry.

This paper presents the automatic code generation process of the academic design of an Attitude Control System (ACS) for the Multi-Mission Platform (MMP). The MMP is a three axis stabilized artificial satellite now under development at the National Institute for Space Research (INPE). Such design applied some software engineering concepts as: 1)visual modeling; 2)automatic code generation; 3)automatic code migration; 4)soft real time simulation; and 5)hard real time simulation. A block diagram based modeling and a virtual time simulation of the MMP ACS in its nominal operational mode were built in the MatrixX 7.1 environment satisfying the three axis pointing and stabilization requirements. After that, its AutoCode module was used to generate C ANSI code representing the block diagram model. Four operating systems were used for code migration: 1)Windows 2000; 2)Mandrake Linux 10.1; 3)RedHawk Linux 2.1; and 4)RTEMS 4.6.2.