bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bounds of Reliability Function for Structural Systems Subjected to Imprecise Seismic Actions
Authors: Genovese Federica , Muscolino Giuseppe , Sofi Alba 
Published: January 2022

Abstract
The present paper focuses on reliability analysis of structural systems under ground motion acceleration taking into account the inherent random nature of the excitation as well as epistemic uncertainties affecting the definition of its spectrum. Specifically, seismic excitation is modelled as a zero-mean stationary Gaussian random process fully characterized by an imprecise power spectral density (PSD) function i.e. with interval parameters. The ranges of such interval parameters are determined by analysing a large set of accelerograms recorded on rigid soil deposits. To discard outliers, the Chauvenet’s Criterion is applied iteratively. The proposed imprecise PSD function may be viewed as representative of the actual accelerograms recorded on rigid soil deposits. Reliability assessment is carried out by incorporating the imprecise PSD function of ground motion acceleration into the formulation of the classical first-passage problem using Vanmarcke’s failure criterion. Due to imprecision of the excitation, the reliability function and the fractile of order p of the selected extreme value response process turn out to have an interval nature. Thus, the aim of reliability analysis is the evaluation of the bounds of such functions which define the range of structural performance. Numerical results show that neglecting imprecision of the PSD may lead to significant overestimation of the safety level.
Simulation of a Terrain Versatile Walker-Wheelchair With Torso Support
Authors: Manzer James , Simon Sosa Gabriel , Piovesan Davide 
Published: January 2022

Abstract
Much of the population have mobility disabilities. A market analysis highlighted the lack of a low-cost mobility solution that could provide terrain versatility, torso support, combined wheelchair functionality, and sit-to-stand assistance. Furthermore, the use of common, readily available parts for device life maintenance is advantageous for the intended use in rural areas.
This study describes a design for a mobility solution. A simulation and analysis are performed using multi-body software to determine the interaction between the vehicle on different types of obstacles, as well as determine forces in the riskiest parts of the design for connection strength analysis.
To complete this simulation, several determinations had to be obtained to use proper constraints for the system, such as the force the caregiver would push with and the damping of the tires. A physical test is performed to find the average force required to push a wheelchair and patient over outdoor, bumpy terrain. This study makes multiple suggestions for mobility device design that contrast with trending design priorities in the medical device industry and provides evidence for these recommendations. The results of the created simulations are used to make design choices regarding wheel configuration and size.
Contrasting the Traditional Engineering and Business Approaches to the Teaching of Engineering Economics
Authors: Armstrong Aaron 
Published: January 2022

Abstract
Engineering economics instruction tends to fall within two approaches, a business-oriented approach similar to what might be taught in a business finance or cost accounting class, and an engineering-based approach which follows the solution methods and general pedagogy used with other engineering topics. These disparate approaches can lead to different learning and performance outcomes for the students of this important topic. This paper provides a background in the various methods for teaching the subject and contrasts these two general approaches. Detailed examples are provided for each approach. The various advantages and disadvantages of each approach are then discussed in terms of their respective instructional techniques and learning outcomes. A survey of the approaches used by textbooks in the topic area is then presented. The respective implications for the instruction of the topic of engineering economics as well as the broader implications for the future of the engineering profession are then discussed with directions toward future development in this area.
The Influence of Plain-Orifice Geometry on Pintle Injector Flow Discharge Coefficient
Authors: Harms Colton , Fazeli Hamid , Vanaken Jordan 
Published: January 2022

Abstract
In this study, an experiment was carried out to understand the behavior of incompressible flow passing through the plain-orifices of pintle injector to characterize the discharge coefficient (Cd) for different orifice geometries. Three types of orifices, including primary, secondary, and film-cooling orifices, were utilized to characterize the discharge coefficient and understand each orifice flow pattern with high-speed imaging. Each of these orifices will be separated and tested in their test article. The impacts of parameters, including shape and size, on discharge coefficient were studied. The discharge coefficient was determined for each test article by subjecting the orifices to a range of flow rates and measuring the pressure differential. The results obtained for the test article F show a good agreement with the choked fit curve obtained from the analytical relation. In contrast, the results of other test articles show an inconsistency due to the cavitation phenomenon as an unstable flow in their trends. However, they show that after the cavitation, they precisely follow the expected trends.
Numerical Investigation Into the Cutting Forces, Chip Formation Mechanism, and Burr Formation During Slot Milling of Laminated CFRP Composites
Authors: Hassan Md Mahmudul , Ma Jeff , Jahan M. P. 
Published: January 2022

Abstract
Carbon Fiber Reinforced Polymer (CFRP) composites have been attracting wide attention to industrial applications, such as in aerospace and automotive industries, because of their superior specific strength/ stiffness, excellent damage tolerance and fatigue life, and outstanding corrosion resistance along with their distinguished thermal and acoustic insulation capacity. The availability of laminated CFRP sheets has made it easy to manufacture many complex shapes accompanied by these wonderful properties Machining (post-processing) the laminated CFRP workpiece is of great importance, as it helps to achieve the desired shapes along with the desired dimensional accuracy. In this research, ABAQUS, a powerful commercial finite element method (FEM) software package, is utilized to model and simulate the milling of laminated CFRP composites. The effect of machining parameters (spindle speed, feed rate, and depth of cut) has been assessed in terms of stress distribution, temperature distribution, cutting forces, burr formation, and material removal mechanisms. In this research, coupled temperature-displacement elements are used in order to capture the effect of machining on both deformation and temperature distribution. A combination of shear damage, ductile damage and Johnson-Cook constitutive and damage models have been used to account for the damages in the fiber and matrix. A total of 12 laminates are stacked together using traction separation laws with quadratic damage cohesive model. Layers with four different fiber orientations (0-135-90-45 degrees) have been stacked. A rigid plate is modeled and attached to the bottom face of the bottom laminate and the reference point of this rigid plate is used to capture the history of cutting forces in three directions. It is found that the maximum cutting forces generated has almost linear relationship with respect to feed rate per revolution as well as with spindle speed. The chip formation mechanism is influenced by the rigidity of the tool, cutting tool geometry, fiber reinforcement directions, and laminate workpiece properties. During machining CFRP composites, failure mechanisms of fibers and matrix are different than those during traditional metal machining. Finally, the simulation results reveal that the ABAQUS FEM model can predict the cutting, stress and temperature distributions, chip formation, and burr formation during machining of CFRP laminate composites.
Concurrent Design for Gravity-Balancing and Rigidity Enhancing of a New Interconnected Manipulator
Authors: Nehad Mostafa Ezz El-Din , Fanni Mohamed , Mohamed Abdelfatah M. 
Published: January 2022

Abstract
Interconnected manipulators possess the advantages of both parallel and serial manipulators to a great extent since they combine the serial and parallel structures inherently, which differentiates them from the hybrid manipulators. However, the passive joints in such manipulators degenerate their rigidity. The gravity balancing of a newly developed interconnected manipulator is achieved by adding springs connecting the driving links with the base. Such springs do not affect the rigidity of the manipulator. In this work, we design a new balancing system where the springs are distributed between the manipulator links without using any auxiliary links. The methodology for balancing this interconnected manipulator depends mainly on dividing it into several serial kinematic chains with passive-revolute joints. Each link of these kinematic chains is transformed into a single-link-equilibrator subsystem which can be easily balanced. The balancing of this subsystem is carried out by attaching a spring between the considered link and a vertical link attached with it by a revolute joint. The distribution of springs between the links transfers the main loads, which are the vertical gravitational loads, to other directions and locations. This new distribution of forces produces lower bending moments and hence decreases greatly the main vertical deflection of the end-effector. The results show that not only the gravity balancing has been achieved, but also the rigidity of the system is greatly enhanced.
Experimental Study of a Piezoelectric Strain-Based Energy Harvester for Intelligent Tires of Autonomous Vehicles
Authors: Aliniagerdroudbari Haniph , Esmaeeli Roja , Farhad Siamak 
Published: January 2022

Abstract
In recent years, autonomous vehicles are at the forefront of the vehicle industry’s attention. Due to the fact that autonomous vehicles are driverless, the safety of these type of vehicles is more important to ensure the passengers safety. To improve the vehicle safety, intelligent tires can be used to provide tire and tire-pavement condition information to the autonomous vehicle control system. For this purpose, intelligent tires are equipped with different sensors such as temperature, pressure, wear and friction. These sensors need a sustainable and reliable power source so that the autonomous vehicle control system has access to the tire information at any conditions. Energy harvesters are proven to be applicable for tire waste strain energy harvesting to provide power for small on-board electronics. In this paper a strain-based energy harvester with the use of piezoelectric material is built and experimentally tested. A measurement system with wireless communication is also developed for online reading of the piezoelectric voltage and power. It is experimentally observed that the generated power by the piezoelectric energy harvester is enough to run the sensors tire. The effects of tire inflation pressure and normal load are also studied on the piezoelectric energy harvester (PEH) output voltage.
Investigation of Skin Material Models for Ballistic Response
Authors: Pandey Punit Kumar , Ganpule Shailesh 
Published: January 2022

Abstract
Skin can be modeled using a variety of material models to depict its mechanical behavior. Skin shows different behavior like anisotropy, nonlinearity, strain rate dependency, viscoelasticity. Several experiments are conducted and presented in the literature for the mechanical characterization of skin. The primary skin material models are elastic, viscoelastic, and hyperelastic. The best suitable material model among them in case of ballistic or penetrating impact is not studied. The objective of this work is to study the sensitivity of choice of material model to the ballistic response. Towards this end, the data from the projectile-skin impact experiments are used to assess the suitability of a specific material model. The number of ballistic impact simulations are performed using 0.16-, 0.49- and 1.1-gram fragment simulating projectile (FSP) using various material models of skin. A dynamic explicit solver LS-Dyna is used to investigate ballistic limit, failure mechanism, and stress-strain responses. Detailed results are presented and discussed in terms of agreement between simulation and experiments against the aforementioned parameters. Viscoelastic material model was found best suitable material for ballistic impact simulation on skin. This work will be helpful in selecting the skin material model for penetrating ballistic impacts.
Analysis of Film Cooling Effectiveness on a Gas Turbine Blade With An Unsteady Wake Using Fast Response Pressure Sensitive Paint
Authors: Sounik Jeremy L. , Wright Lesley M. 
Published: January 2022

Abstract
The transient effect of unsteady wakes on film cooling effectiveness using a fast response pressure sensitive paint (PSP) was studied. Testing was performed in a five passage, low speed wind tunnel using a scaled-up high pressure, blade profile. The blowing ratios studied include 0.4, 0.8 and 1.2 with a density ratio of 1.0 at each blowing ratio. Upstream unsteady wakes were produced by a spoked wheel type wake generator. The wake generator produced Strouhal numbers of 0.1 and 0.3 while the wind tunnel inlet mainstream Reynolds number was held at a constant value of 300,000 for every test case. The results in this paper confirm the overall time averaged reduction in film cooling effectiveness with the addition of an unsteady wake while providing more detailed information on the transient response of the film cooling effectiveness, presented in the form of film cooling effectiveness RMS values. Results show that film cooling effectiveness RMS values follow the same general trends as film cooling effectiveness values in relation to Strouhal numbers. The RMS values increase on the leading edge region of the blade and decrease on the suction side of the blade with an increase in Strouhal number. The pressure side of the blade shows little change in both film cooling effectiveness and film cooling effectiveness RMS values when increasing the Strouhal number.
Current Status and Prospects of Multi-Jet Fusion (MJF) Based 3D Printing Technology
Authors: Singh Aman Preet , Pervaiz Salman 
Published: January 2022

Abstract
Additive manufacturing has been of interest in the recent years due to its popularity in small scale production and rapid prototyping. There is a wide variety of additive manufacturing processes that are practiced today such as Material Extrusion, Material Jetting, Binder Jetting and more. Although, quite a few of these processes generally offer low build rate, resolution and mechanical performance when compared to other machining processes. To overcome these flaws, a technique called Multi Jet Fusion (MJF) has been developed by HP in 2016. MJF utilizes an inkjet array of fusing and detailing agents that are carefully applied across a bed of powdered material layer by layer, which then are fused together by a heating element. MJF offers low machining time, competitive part properties and minimal post production finishing, which all are desirable for various industry applications. In this paper, a comprehensive review of MJF technology will be presented. The review will discuss and evaluate principle operation of MJF, current knowledge of material characteristics, chemical, thermal, and mechanical properties of printed parts, parameters affecting the properties, its potential when compared to other similar technologies and future scope. This paper shall help serve as a guideline for 3D printing with MJF technology in the industry.
Numerical Analysis of Multiple Jets Impinging on a Moving Surface
Authors: Barbosa Flavia , Teixeira Jose , Silva João , Teixeira Senhorinha 
Published: January 2022

Abstract
Multiple jet impingement is an effective heat transfer process that enables uniformization of the cooling process. In addition to flow and geometry variables, the motion of the target plate is paramount to several applications, such as reflow soldering process, food processing, drying, and heat treatments, which increases the complexity of the flow over the surface. This work analyses numerically the effect of the target plate motion in multiple jet impingement performance and compares the results with a static plate case. To conduct this research, a widespread commercial software, the ANSYS FLUENT, is used. Between the different turbulence models available to conduct the numerical simulations, the SST k-ω model is implemented since it provides accurate predictions of impinging flows at reduced computational costs. From the numerical modeling, a detailed characterization of the flow is performed, and the heat transfer is analyzed at the vicinity of the target plate. Since a low nozzle-to-plate distance (H/D = 2) and jet-to-jet spacing (S/D = 3) are implemented, strong interactions between jets are identified. These interactions are well predicted in both static and moving plates. Jet’s shear layer interactions are observed prior to the impingement as well as wall jets collisions over the surface. Moreover, the increased turbulence intensity of the flow, induced by the plate motion, is accurately predicted by the numerical model. Strong shear layers, generated in direction to the motion, are observed, which leads to a modification of the boundary layer compared with the static plate. This effect increases the local heat transfer rate over the moving plate as well as the complexity of the flow compared with the static plate.
A Numerical Study to Investigate Machining Aspects of Convex Surface Drilling
Authors: Lewis Jonathan , Pervaiz Salman , Kannan Sathish 
Published: January 2022

Abstract
Metallic alloys with convex curved surfaces have large scale applications in several industries such as in the automotive, marine and aerospace industries. These curved surfaces are used in the applications where surface integrity is extremely important. A large amount of research has been conducted related to the finishing processes, such as surface milling, that improve the finish quality of the manufactured part. However, there is a lack of knowledge of on how the curvature of the parts affect machining performance. Drilling of non-flat surfaces are not easier to conduct due to slippage and less accuracy. The cutting mechanism on the conventional drilling process is well studied in the conventional metal cutting literature, but on curved non-flat surfaces it is not studied. The thrust force signature in convex curved surface drilling is different from the conventional drilling because of the difference in engagement of chisel edge and cutting lips. It is also observed in the conventional drilling process that cutting parameters such as feed rate and cutting speed have controlling influence on the drilling performance. There is a need to investigate the influence of these cutting parameters on convex curved surfaces as well. Similarly chip clogging and evacuation are very important and decisive factors in the conventional drilling. It would be interesting to visualize and discuss these factors in convex surface drilling. In the case of convex surface drilling, curvature of surface being drilled is also an important factor that can limit the drilling process. The curvature of surface also defines the tool – workpiece engagement and cutting action of chisel edge and cutting lips. Due to convex curved surface, variation in chip load is expected due to variation in the cutting area.
Titanium alloy Ti6Al4Vis a commonly used alloy used in the aerospace industry. The aim of this study was to investigate the effects of curvature of a titanium alloy, Ti6Al4V, on the cutting forces experienced during the drilling process. The effects of the curvature of the surface were compared to the effects of the cutting speed and feed rate, in order to establish the significance of the effect of the curvature compared to other factors that affect the drill machining process. The effects of these parameters on the power and temperature during the drilling process were also analyzed and compared. The study is beneficial for the metal cutting academia and industry as it can provide the basic understanding and open up new areas of application.
Tailored Energy Absorption for 3D Printed Multi-Material Cellular Structures Using ABS and TPU
Authors: Khatri Nava Raj , Egan Paul F. 
Published: January 2022

Abstract
Advances in multi-material 3D printing technologies are enabling the construction of advantageous engineering structures for diverse applications. Multi-material printing allows the combination of contrasting engineering materials in a single part to gain synergistic performance increases. Cellular structure such as honeycomb structures provide high-energy absorption to weights ratio that could benefit through multi-material strategies for tailored responses in applications such as design of helmets and prosthetics. In this study, we investigate the compressive response and the energy absorption for combinations of acrylonitrile butadiene styrene (ABS) and thermoplastic polyurethane (TPU) printed lattices. Results demonstrate energy absorption increases from pure TPU samples of 2.18kN.mm in a non-linear fashion to pure ABS samples of 11.47kN.mm as bands of TPU are added to ABS. Splitting a single band of TPU into multiple bands with the same total thickness changes the behavior of first and second peak before densification. Testing with in-plane loading demonstrated more similar behavior among the differently designed multi-material lattices, with collapsing occurring with sequential failures of unit cell rows. These results demonstrate the feasibility in constructing multi-material lattice systems with ABS and TPU combinations, while highlighting their benefits for enabling controlled energy absorption and deformation responses based on designed material combinations.
Structure-Borne Power Flow Sensitivity Analysis for General Structural Modifications
Authors: Young Jon , Myers Kyle 
Published: January 2022

Abstract
Power flow between source and passive receiver structures is a common metric for characterizing the dynamics of coupled structures. The objective is generally to reduce the amount of power flow between the structures by means of structural modifications, insofar as to reduce the overall levels of vibration of the coupled system. As such, the sensitivity of power flow to changes in inertial, elastic, and dissipative properties of the structure is quantified. It is shown that power flow into a receiver is not always directly proportional to the amount of damping in the receiver, but is also dependent on the amount of damping present in the source at a given frequency. The sign of the sensitivity can provide information as to when a change in damping will increase or decrease power flow; positive indicates an increase in power flow, negative indicates a decrease. A similar analysis is performed on modifications made to a structure’s mass and stiffness properties. Relationships between power flow and power flow sensitivity are shown for a simple single degree of freedom source-receiver coupling, and is extended to a multi-degree of freedom coupling between two beam structures.