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Technical Paper

Investigating Collaborative Robot Gripper Configurations for Simple Fabric Pick and Place Tasks

2019-04-02
2019-01-0699
Fiber composite materials are widely used in many industrial applications - specially in automotive, aviation and consumer goods. Introducing light-weighting material solutions to reduce vehicle mass is driving innovative materials research activities as polymer composites offer high specific stiffness and strength compared to contemporary engineering materials. However, there are issues related to high production volume, automation strategies and handling methods. The state of the art for the production of these light-weight flexible textile or composite fiber products is setting up multi-stage manual operations for hand layups. Material handling of flexible textile/fiber components is a process bottleneck. Consequently, the long term research goal is to develop semi-automated pick and place processes for flexible materials utilizing collaborative robots within the process. Collaborative robots allow for interactive human-machine tasks to be conducted.
Technical Paper

Behavior of Adhesively Bonded Steel Double-Hat Section Components under Lateral Impact Loading

2018-04-03
2018-01-1447
Recent experimental studies on the behavior of adhesively-bonded steel double-hat section components under axial impact loading have produced encouraging results in terms of load-displacement response and energy absorption when compared to traditional spot-welded hat- sections. However, it appears that extremely limited study has been carried out on the behavior of such components under transverse impact loading keeping in mind applications such as automotive body structures subject to lateral/side impact. In the present work, lateral impact studies have been carried out in a drop-weight test set-up on adhesively-bonded steel double-hat section components and the performance of such components has been compared against their conventional spot-welded and hybrid counterparts. It is clarified that hybrid components in the present context refer to adhesively-bonded hat-sections with a few spot welds only aimed at preventing catastrophic flange separations.
Technical Paper

One-Dimensional Modelling and Analysis of Thermal Barrier Coatings for Reduction of Cooling Loads in Military Vehicles

2018-04-03
2018-01-1112
There is a general interest in the reduction of cooling loads in military vehicles. To that end thermal barrier coatings (TBCs) are being studied for their potential as insulators, particularly for military engines. The effectiveness of TBCs is largely dependent on their thermal properties, however insulating effects can also be modified by applying different coating thickness. Convection from in-cylinder surfaces can also be affected by manipulation of surface structure. Although most prior studies have examined TBCs as a means of increasing efficiency, military vehicle design is primarily concerned with the reduction of cylinder heat transfer to allow downsizing of cooling systems. A 1-D transient conjugate heat transfer model was developed to provide insight into the effects of different TBC designs and material selection on cooling loads. Results identify low thermal conductivity and low thermal capacitance as key parameters in achieving optimal heat loss reduction.
Journal Article

An Exploration of Jute-Polyester Composite for Vehicle Head Impact Safety Countermeasures

2018-04-03
2018-01-0844
Natural fiber-reinforced composites are currently gaining increasing attention as potential substitutes to pervasive synthetic fiber-reinforced composites, particularly glass fiber-reinforced plastics (GFRP). The advantages of the former category of composites include (a) being conducive to occupational health and safety during fabrication of parts as well as handling as compared to GFRP, (b) economy especially when compared to carbon fiber-reinforced composites (CFRC), (c) biodegradability of fibers, and (d) aesthetic appeal. Jute fibers are especially relevant in this context as jute fabric has a consistent supply base with reliable mechanical properties. Recent studies have shown that components such as tubes and plates made of jute-polyester (JP) composites can have competitive performance under impact loading when compared with similar GFRP-based structures.
Technical Paper

Direct Laser Metal Deposition of Al 7050 Alloy

2017-03-28
2017-01-0286
Additive manufacturing (AM) of metals is finding numerous applications in automotive industry. In 21st century, aluminum is second to steel in automotive sector, because of its high strength to weight ratio. Hence developing AM for aluminum alloys become necessary to make sure industry gains maximum benefit from AM. This study specifically deals with the manufacturing of Al 7050 alloy, which is quite hardest alloy to manufacture using AM. The ultimate goal is to optimize the laser deposition parameters to deposit defect free Al 7050 alloy on rolled aluminum alloy substrate. Parameter optimization (laser power, powder flow rate, and scanning speed) gets difficult with the presence of various low melting and boiling point alloying elements such as Zn, Mg etc. Numerous other challenges faced while depositing Al 7050 alloy, are also briefly discussed in this article. Microstructural investigation using optical and scanning electron microscopy confirms greater than 99% component density.
Technical Paper

Prediction of the Behaviors of Adhesively Bonded Steel Hat Section Components under Axial Impact Loading

2017-03-28
2017-01-1461
Adhesively bonded steel hat section components have been experimentally studied in the past as a potential alternative to traditional hat section components with spot-welded flanges. One of the concerns with such components has been their performance under axial impact loading as adhesive is far more brittle as compared to a spot weld. However, recent drop-weight impact tests have shown that the energy absorption capabilities of adhesively bonded steel hat sections are competitive with respect to geometrically similar spot-welded specimens. Although flange separation may take place in the case of a specimen employing a rubber toughened epoxy adhesive, the failure would have taken place post progressive buckling and absorption of impact energy.
Technical Paper

Effect of Strain Rate on Mechanical Responses of Jute-Polyester Composites

2017-03-28
2017-01-1467
There has been a keen interest in recent times on implementation of lightweight materials in vehicles to bring down the unladen weight of a vehicle for enhancing fuel efficiency. Fiber-reinforced composites comprise a class of such materials. As sustainability is also a preoccupation of current product development engineers including vehicle designers, bio-composites based on natural fibers are receiving a special attention. Keeping these motivations of lower effective density, environment friendliness and occupational safety in mind, woven jute fabric based composites have been recently studied as potential alternatives to glass fiber composites for structural applications in automobiles. In the past, mechanical characterization of jute-polyester composites were restricted to obtaining their stress-strain behaviors under quasi-static conditions.
Technical Paper

Crack Failure Mode Analysis for Cam-Housing Rocker Arm and Pin

2017-03-28
2017-01-0358
During the extensive testing under NATO and Commercial Standards, crack is observed in camshaft housing to initiate from the eccentric shaft bore and go toward the hold down bolt hole. Hence lab test proposal is originated to induce similar failure in a controlled method and then to compare new design alternatives. CAE analysis follows the same set up as the lab test to duplicate failure mode in stress analysis and fatigue analysis with duty cycle loads, and then figures out two strategies on how to improve the design, including geometry change and material change. In geometry wise, four new design iterations are evaluated for comparison. In material wise, one new material for camshaft housing and five manufacturing effect parameters for pin and rocker arm are compared, including ground, machined, machined and decarburization, casting, as well as casting and nitride. With those comparisons, all manufacturing parameters are compared based on effectiveness to affect the fatigue life.
Technical Paper

Influence of Oxygen Concentration on the Auto-Ignition and Flame Propagation Characteristics of Diesel Jets with Experimental Comparison

2017-03-28
2017-01-0842
Numerical simulations of diesel reacting jets in a simulated engine environment were carried out to study the effect of oxygen concentration on the ignition delay time and lift-off length dynamics. A recently developed mechanism, direct integration of chemistry, and well established Lagrangian-Eulerian spray model were utilized for 3-D turbulent spray combustion simulation under engine like conditions. The simulations are able to provide a time-history of chemical species including formaldehyde CH2O intermediates and hydroxide OH radicals to facilitate development of auto-ignition and lift off length numerical diagnostics. A range of important operating points including variations in the oxygen concentration, rail pressure, and injection duration were examined. The purpose of conducting the parametric studies is to investigate the consistency of the results and provide a more comprehensive analysis than a single point condition.
Technical Paper

Simulation and Comparison of Autoignition of Homogeneous Fuel/Air Mixtures and Sprays in Diesel Engines

2016-04-05
2016-01-0311
All previous correlations of the ignition delay (ID) period in diesel combustion show a positive activation energy, which means that shorter ID periods are achieved at higher charge temperatures. This is not the case in the autoignition of most homogeneous hydrocarbons-air mixtures where they experience the NTC (Negative Temperature Coefficient ) regime in the intermediate temperature range, from about 800 K to 1000 K). Here, the autoignition reactions slow down and longer ID periods are experienced at higher temperatures. Accordingly the global activation energy for the autoignition reactions of homogeneous mixtures should vary from positive to negative values.
Technical Paper

Development Of A Practical Multi-disciplinary Design Optimization (MDO) Algorithm For Vehicle Body Design

2016-04-05
2016-01-1537
The present work is concerned with the objective of developing a process for practical multi-disciplinary design optimization (MDO). The main goal adopted here is to minimize the weight of a vehicle body structure meeting NVH (Noise, Vibration and Harshness), durability, and crash safety targets. Initially, for simplicity a square tube is taken for the study. The design variables considered in the study are width, thickness and yield strength of the tube. Using the Response Surface Method (RSM) and the Design Of Experiments (DOE) technique, second order polynomial response surfaces are generated for prediction of the structural performance parameters such as lowest modal frequency, fatigue life, and peak deceleration value. The optimum solution is then obtained by using traditional gradient-based search algorithm functionality “fmincon” in commercial Matlab package.
Technical Paper

Behavior of Adhesively Bonded Steel Double Hat-Section Components under Axial Quasi-Static and Impact Loading

2016-04-05
2016-01-0395
An attractive strategy for joining metallic as well as non-metallic substrates through adhesive bonding. This technique of joining also offers the functionality for joining dissimilar materials. However, doubts are often expressed on the ability of such joints to perform on par with other mechanical fastening methodologies such as welding, riveting, etc. In the current study, adhesively-bonded single lap shear (SLS), double lap shear (DLS) and T-peel joints are studied initially under quasi-static loading using substrates made of a grade of mild steel and an epoxy-based adhesive of a renowned make (Huntsman). Additionally, single lap shear joints comprised of a single spot weld are tested under quasi-static loading. The shear strengths of adhesively-bonded SLS joints and spot-welded SLS joints are found to be similar. An important consideration in the deployment of adhesively bonded joints in automotive body structures would be the performance of such joints under impact loading.
Journal Article

A Comparison of the Behaviors of Steel and GFRP Hat-Section Components under Axial Quasi-Static and Impact Loading

2015-04-14
2015-01-1482
Hat-sections, single and double, made of steel are frequently encountered in automotive body structural components. These components play a significant role in terms of impact energy absorption during vehicle crashes thereby protecting occupants of vehicles from severe injury. However, with the need for higher fuel economy and for compliance to stringent emission norms, auto manufacturers are looking for means to continually reduce vehicle body weight either by employing lighter materials like aluminum and fiber-reinforced plastics, or by using higher strength steel with reduced gages, or by combinations of these approaches. Unlike steel hat-sections which have been extensively reported in published literature, the axial crushing behavior of hat-sections made of fiber-reinforced composites may not have been adequately probed.
Technical Paper

An Alternative Approach for Formulation of a Crushable PU Foam Considering its Behavior under Compressive Loads

2015-04-14
2015-01-1483
Rigid polyurethane (PU) foam finds wide applications as a lightweight material in impact safety design such as improving occupant safety in vehicle crashes. The two principal reacting compounds for formulating such foam are variants of polyol and isocyanate. In the present study, an alternative mechanical engineering-based approach for determining, with confidence, the desirable ratio of reacting compounds for formulation of a rigid/crushable PU foam for mechanical applications is demonstrated. According to the present approach, PU foam samples are prepared by varying the mixing ratio over a wide range. The desirable mixing ratio is shown to be the one that optimizes key mechanical properties under compression such as total absorbed energy, specific absorbed energy and energy absorption efficiency.
Technical Paper

Effects of Sinusoidal Whole Body Vibration Frequency on Drivers' Muscle Responses

2015-04-14
2015-01-1396
Low back pain has a higher prevalence among drivers who have long term history of vehicle operations. Vehicle vibration has been considered to contribute to the onset of low back pain. However, the fundamental mechanism that relates vibration to low back pain is still not clear. Little is known about the relationship between vibration exposure, the biomechanical response, and the physiological responses of the seated human. The aim of this study was to determine the vibration frequency that causes the increase of muscle activity that can lead to muscle fatigue and low back pain. This study investigated the effects of various vibration frequencies on the lumbar and thoracic paraspinal muscle responses among 11 seated volunteers exposed to sinusoidal whole body vibration varying from 4Hz to 30Hz at 0.4 g of acceleration. The accelerations of the seat and the pelvis were recorded during various frequency of vibrations. Muscle activity was measured using electromyography (EMG).
Technical Paper

Use of Truncated Finite Element Modeling for Efficient Design Optimization of an Automotive Front End Structure

2015-04-14
2015-01-0496
The present work is concerned with the objective of multi disciplinary design optimization (MDO) of an automotive front end structure using truncated finite element model. A truncated finite element model of a real world vehicle is developed and its efficacy for use in design optimization is demonstrated. The main goal adopted here is minimizing the weight of the front end structure meeting NVH, durability and crash safety targets. Using the Response Surface Method (RSM) and the Design Of Experiments (DOE) technique, second order polynomial response surfaces are generated for prediction of the structural performance parameters such as lowest modal frequency, fatigue life, and peak deceleration value.
Technical Paper

Door Slam CAE Method Investigation

2015-04-14
2015-01-1324
Nowadays, as an irreplaceable means alongside CAD and testing, CAE is more and more widely applied with advanced material modeling and simulation methods continuously being explored, so as to get more accurate result as testing. In vehicle product development process, door slam durability evaluation is an important measurement for body closure structure. So far numerous effort has been taken to develop more mature methods to well define door slam simulation in stress and fatigue life analysis. Overall all methods ever being applied can be summarized as two categories, linear stress based method and nonlinear stress based method. The methodologies, such as inertia relief method, direct transient response solution, or local strain approach, can be included in linear stress based method with linear material properties as symbol in CAE model. In local strain approach, contact surface could be defined in the necessary area with consideration for more realistic load transfer.
Journal Article

A New Device for Multi-Axial Tissue Testing: Application to Combined Bending and Shear Loading of the Spine

2009-04-20
2009-01-0249
A multi-axial test device was designed to obtain the material properties of the lumbar spine in combined loading modes. The custom designed tester consists of a rigid platen driven by three DC powered geared motors. Two motors, each connected to parallel linear actuators control the angular displacement (for flexion and extension) and vertical motion (for tension and compression), while a third DC motor connected to a threaded rod was employed to control the horizontal displacement (for anterior and posterior shear) of the rigid platen. The testing machine is driven in displacement-control mode by a feedback system based on data from three rotary potentiometers. Six entire lumbar spine segments (T12-S1) were potted in aluminum cups with DynaCast and tested within failure limits to compression, tension, anterior shear, posterior shear, flexion, extension, anterior shear-flexion, posterior shear-extension and finally in combined anterior shear-flexion loading.
Journal Article

Characterization of Diesel Common Rail Spray Behavior for Single- and Double-hole Nozzles

2008-10-06
2008-01-2424
Double-hole nozzle and multiple injections have the potential for better fuel atomization and mixing in DI engine. In order to evaluate the behavior of the spray for the double-hole nozzles against traditional single-hole ones, high-speed spray visualization was carried out using a streak film camera and a copper vapor laser, and in combination with a long-distance camera when taking microscopic movies. The spray penetration and the cone angle were measured based on the images and compared for variable injection pressures, and for single and split injections, under ambient and elevated chamber pressure conditions. The results showed that the spray of the double-hole nozzle has comparable penetration but smaller cone angle when viewed from the nozzle end, compared to the single-hole nozzle with the same total hole discharge cross-sectional area. For microscopic view, it was observed that the interaction between the dual sprays is very dynamic.
Technical Paper

Fatigue Resistance of Short Fiber-Reinforced TiNi/Al6061-SiC Composite

2007-04-16
2007-01-1423
The short NiTi fiber-reinforced NiTi/Al6061-SiC composite was recently developed through the U.S. Army SBIR Phase-II program [1]. The objectives of this project are to use short NiTi fiber reinforcement to induce compressive stress through shape memory effect, to use silicon carbide (SiC) particulate reinforcement to enhance the mechanical properties of the aluminum matrix, to gain fundamental knowledge of short NiTi fiber-reinforced aluminum matrix composite, and eventually to improve fatigue resistance, impact damage tolerance and fracture toughness of the composite. The fatigue life, damage and fracture behavior of TiNi/Al6061-SiC, TiNi/Al6061, Al6061-SiC composites as well as monolithic Al6061 alloy were investigated under fully reversed cyclic loading. It was found that fatigue life of NiTi/Al6061-SiC composite, in term of the cycles, increased by two orders of magnitude, compared to monolithic Al6061 alloy
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