bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Loading Frequencies on Fatigue Strength of Aluminum 6061-T6
Authors: Le Xiaobin
Published: February 2023

Material fatigue properties include a fatigue strength at a given number of cyclic stresses and fatigue life at a specified cyclic stress level. Typically, provided material fatigue properties don’t show or specify whether there is any effect of cyclic loading frequency on fatigue strength. Some research concluded that the effects of cyclic loading frequency on fatigue strength are very limited and can be ignored. But some research indicated that there are significant effects of cyclic loading frequency on fatigue strength and cannot be ignored. Lots of literature evaluates the effects of ultrasonic load frequencies on material fatigue strength. But most of the component failures in industries are due to the not-ultrasonic cyclic stresses which are typically induced by rotating unbalance or mechanical vibration. When evaluating the effects of load frequencies on material fatigue strength, a lot of literature compared the S-N curves. But metal fatigue is the initiation and propagation of inherent defects or cracks in a component due to cyclic loading. Because inherent defects or cracks are randomly distributed and randomly initiated ins a component, fatigue failure is a random event. This paper studies the effects of loading frequencies on Aluminum 6061-T6 fatigue strength. Five groups of fatigue tests are conducted on the same specimen under the same cyclic axial load but at varying frequencies of 10 Hz, 20 Hz, 30 Hz, 40 Hz, and 50 Hz. Each group will have more than 30 tests. Then we evaluate the effects of load frequencies on material fatigue strength by comparing the distributions of the fatigue life. The T-Test is used to check whether the effects of load frequencies on the fatigue strength are statistically significant differences or not.
Computational and Mathematical Models to Assess Early Stages Abdominal Aortic Aneurysm (AAA) Growth
Authors: AL-Rawi Mohammad , Al-Jumaily Ahmed , Belkacemi Djelloul
Published: February 2023

Cardiovascular diseases such as Abdominal Aortic Aneurysm (AAA) can be effectively modelled for biomechanical studies using computational and mathematical tools enabling development of non-invasive algorithms for disease diagnoses. AAA is usually infrarenal and occurs when the abdominal aorta balloons abnormally, wherein a major expansion (at least one and half times the diameter of healthy aorta) to the lumen diameter leads to a decrease in blood supply to key organs and limbs, as well as the possibility of artery rupture. A realistic abdominal aorta for a patient showing the potential for AAA growth is investigated using ANSYS®2021 R1 Fluent after converting 2D MRI images (segments) to a 3D model considering the abdominal aorta and the iliac bifurcation. The 3D model is analysed using clinical boundary conditions presented as the blood waveform at the inlet of the aorta and the pressure waveforms at the outlet of the iliac bifurcation using Two-Way Fluid-Structure Interaction (FSI) methods. In this study, the wall shear stress (WSS) and circumferential strain (CS) are investigated at four different times: 0.15s when the aortic valve opens; 0.35s at the systolic pressure; 0.45s when the aortic valve closes; and 0.85s at diastolic pressure based on the propagated waveforms. The abdominal aorta is examined using Non-Newtonian Carreau-Yasuda blood flow properties for specific patient data. The phase angle (PA) between WSS and CS shows the effect of early-stage abdominal aorta geometry growth rate due to the risk of aneurysm growth, on wave propagations with a range 200° to −180°.
A Robust Hybrid Machine Learning-Based Modeling Technique for Wind Power Production Estimates
Authors: Banerjee Amit , Abu-Mahfouz Issam , Tian Jianyan , Rahman A. H. M. Esfakur
Published: February 2023

The need to accurately estimate wind power is essential to the design and deployment of individual wind turbines and wind farms. The estimation problem is framed as wind power curve modeling. Lately, machine learning techniques have been used to model power curves and provide power estimates. Such models rely on the fact that all outliers are removed from the raw wind data before they are used in modeling and estimation since outliers can adversely affect performance. However, generating outlier-free data is not always possible. Robust models and robust objective functions can be two effective ways to obtain accurate power curves in the presence of outliers. In this paper, a robust density-based clustering technique (DBSCAN) to first identify outliers in the dataset is proposed, followed by artificial neural network (ANN) models that are trained using the outlier-free data to obtain accurate power curve estimates. ANNs are trained using a range of optimization methods and are compared in this study. Preliminary results show the proposed method is superior to probabilistic models that use error-functions to generate accurate power curves and that the proposed hybrid model can generate more accurate power output estimations in the presence of outliers compared to deterministic models such as integrated curve fitting models that are known to be robust.
Heterogeneous Beam Element Based on Timoshenko Beam Model
Authors: Chiu Rong , Yu Wenbin
Published: February 2023

Traditional multiscale methods homogenize a beam-like structure into a material point in 1-D continuum with effective properties computed over a structure gene in terms of a cross-section or a 3D segment with spanwise periodicity. Such methods lose accuracy when dealing with real world beam-like structures usually not uniform or periodic along the spanwise direction. Thus, traditional multiscale methods cannot be rigorously applied to these cases. In our previous work, a new multiscale method was proposed based on a novel application of the recently developed Mechanics of Structure Genome (MSG) to analyze beam-like structures. Beam-like structures were homogenized into a series of 3-node Heterogeneous Beam Elements (HBE) with 18 × 18 effective beam element stiffness matrices, which were used as input for one-dimensional beam analyses. However, due to the shape function limitations, HBE could not handle transverse shear loads. In this work, the shape functions and the MSG theory are further modified to enable capabilities of HBE for transverse shear loads. Using the macroscopic behavior of the beam elements as input, dehomogenization can be performed to predict the local stresses and strains in the original structure. Two examples are used (a periodic composite beam and a tapered beam) to demonstrate the capability of this improved HBE.
Artificial Neural Network for Automatic Prediction of the Surface Finishing via Classification of the Surface Texture
Authors: Alqahtani Hassan , Ray Asok
Published: February 2023

In this study, the effects of the machining type on the notch of a specimen, made of 7075-T6 aluminum alloy, have been investigated. The CNC machining and waterjet cutting are used to machine specimens for in fatigue testing. The surface texture characterization, resulting from machining, is examined by using an optical metrology device (Alicona). The tested surface texture is characterized by the average height, Ra, over a small selected range of data. The effect of the stress concentration was studied by designing the surface texture using a computer-aided design (CAD) tool. It is observed that the waterjet cutting produces very rough surfaces, hence increasing the fatigue stress concentration. In addition, this study presents an automated prediction for the machining type using the tools of artificial intelligence (AI), where a neural network (NN) is applied to predict the machining type, which is based on the extracted surface textures, derived from the measurement data. The classification methodology, which uses a NN model, has been built based on the concept of pattern recognition. Results of this study show that the NN model is capable of successfully predicting the type of surface roughness with (up to) 90% accuracy.
Manufacturing and Characterization of Nanocomposites With Antibacterial Nanoparticles
Authors: Billings Christopher , Kim Peter , Cai Changjie , Liu Yingtao
Published: February 2023

This paper will present the advanced manufacturing of a novel nanocomposite utilizing digital light processing (DLP) based 3D printing technology. The novel nanocomposite will be manufactured from a photocurable resin and zinc oxide in the 10–30 nm range with varying volume fraction ratios. Weight concentrations of 1–5% will be analyzed concerning tensile strength, water contact angle, and dispersion. In addition, samples will be examined through a scanning electron microscope (SEM) to demonstrate the lack of particle aggregation and voids within the part. The nanocomposites produced demonstrated a significant strength increase at 5% concentrations and an increase in water contact angle. An ultimate tensile strength of 39.51 Mpa was achieved on average compared to the neat resin control value of 31.63 Mpa. In addition, SEM analysis illustrated a properly dispersed nanoparticle with low amounts of agglomeration. The utilization of zinc oxide (ZnO) as a mechanical additive in DLP manufacturing demonstrated a novel method for increasing part strength with functional nanoparticles. Due to the design freedom gained with additive manufacturing, nanocomposites produced promise a greater strength-to-weight ratio than those manufactured through traditional methods.
Comparison of Ballistic Impact Simulations Using Different Constitutive Material Models of Concrete
Authors: Duncan Chris , Perkins Richard Allen , Johnson Daniel , Chandler Mei , Moser Robert , Sherburn Jesse , Hammi Youssef
Published: February 2023

Concrete is a widely implemented material in simulation codes and understanding its response in different loading scenarios is of interest to researchers. Notably, concrete is an extremely versatile material for many different types of applications due to its ability to withstand high compressive loading conditions at an affordable cost. For this reason, it is of a strong interest to many researchers. Specifically, understanding the response of the concrete materials in ballistic loading conditions is of importance for scenarios such as military and defense applications. Furthermore, computational models have been developed to simulate the response of contentious materials in these loading conditions. In our study, a computational finite element analysis is conducted to evaluate the response of the high strength concrete denoted as BBR9. The mechanical response of this concrete is captured using two constitutive material models denoted as the Concrete Damage and Plasticity Model 2 (CDPM2) and the Holmquist-Johnson-Cook (HJC) concrete model. In this study, the material parameters of these concrete models are calibrated using existing experimental data found in literature. Specifically, confined triaxial compression and uniaxial compressive experiments (for multiple strain rates) are used to determine the parameters which are implemented to define the response of the BBR9 concrete for each material model. These calibrated material models are implemented to conduct finite element simulations to capture the ballistic impact response of the BBR9 concrete. The finite element simulations are conducted using impact velocities ranging from 300m/s to 1300m/s to present a wide ranged assessment of the energy transfer between the projectile and the BBR9 concrete targets due to the impact. Additionally, for our study a BBR9 target thickness of 25.4mm and a simple spherical projectile is considered. A numerical assessment of the material models is presented by comparing the impact velocity against the residual velocity for each simulation point considered in this study. These results present an assessment of the concrete models and also provides a conceptual validation of their responses. The material models are also qualitatively compared through crater and scabbing diameter results of the targets. The CDPM2 model presents scabbing on the front and rear surfaces of the concrete target, while the HJC model shows cratering of the impact site. Additional experimental studies are warranted to assess the response of this concrete under ballistic loads. Further, future experimental studies can be used to validate these finite element constitutive material models in the appropriate referent of the ballistic impacts.
Creep-Fatigue Reliability Analysis Integrated With Surrogate Modelling: Application on Industrial Case Studies
Authors: Wang Run-Zi , Suzuki Ken , Miura Hideo , Zhang Xian-Cheng , Tu Shan-Tung
Published: February 2023

In pursuit of carbon neutral goal, the service conditions of many industrial structures in aero-engine systems, gas turbines and fire-power equipment are going to be harsher to improve high energy conversion efficiency. In terms of rotating components undergoing start-up, steady service and shut down periods, complicated creep-fatigue interaction causes a primary failure mode that restricts the lifetimes of materials and structures and poses severe challenge in structural integrity. The objective of this study is, therefore, to establish an accurate and efficient creep-fatigue reliability analytical framework from material-level to component-level. The data-driven surrogate modeling was integrated into this framework, facilitating rich insight into high reliable life assessment of industrial applications without a large number of high-fidelity and time-consuming finite element analysis cases. In particular, a novel technical route was proposed for probabilistic creep-fatigue evaluation with considering multi-sources of uncertainty. Herein, the typical component of low-pressure turbine disk was applied to case studies to demonstrate how to perform creep-fatigue reliability assessment by using this technical route in practice.
SMA-Based Haptic Gloves Usage in the Smart Factory Concept: XR Use Case
Authors: Srivastava Rupal , Kuts Vladimir , Souza Gouveia Eber Lawrence , Murray Niall , Devine Declan , O’Connell Eoin
Published: February 2023

Conceptualization of the Smart Factory started with introducing the Industry 4.0 paradigm and its nine pillars, which it stands. The paradigm itself is automation and robot-centric focused, which means less and less involvement of the humans on the manufacturing shop floor. However, even robots and simulation aspects of the factories are the most crucial aspects; Industry 4.0 still focuses on the Augmented and Virtual Reality (AR and VR input methods for the human operators, making the smooth transition to the Industry 5.0 concept a human-centric. Although VR/AR is still being enabled and widely used in the Human-Robot Interaction (HRI) research aspect, the heavy headset is limited in the observation field of view. The input methods, such as headsets, have voice and gesture recognition; however, those are mainly limited by factory noise and cameras pointing to the human hands. These headsets constrain the use of smart wearables to a given boundary inside the factory environment. A Shape Memory Alloy (SMA) based haptic glove with discrete data outputs from the kinaesthetic analysis of the hand bending can remove the need for gesture recognition. The paper proposes a modular framework using the SMA-based Haptic Gloves in the Smart Manufacturing environment. These gloves, without additional wearables, can enable interactions with heavy machinery, screens, and all other assets of the industrial area, even with holographic. In this paper, the authors aim to prose the context, design, and framework with the chosen use-cases mainly based on the robotic system applications in the Technological University of the Shannon: Midlands Midwest (TUS: MMW), Ireland, and Tallinn University of Technology (TalTech), Estonia.
Wearable and Stretchable Piezoelectric Energy Harvesting Device Based on Thin Film of ZnO
Authors: Voiculescu Ioana , Fang Shuo , Li Fang
Published: February 2023

This conference paper presents a stretchable piezoelectric power generator device for energy harvesting. The power generator was fabricated from zinc oxide (ZnO) piezoelectric thin film, gold (Au) electrodes for power harvesting and polymer material as substrate. The microfabricated power generator has the thickness in the micrometer scale to be attached on the skin or garments and stretched by the natural movements of arms, legs or neck. The novelty of this research is to use a uniform film of ZnO deposited at low temperature on a large substrate area on the order of centimeter scale. The challenge of this research is to fabricate the ZnO film on a polymeric substrate without a significant reduction of piezoelectric performance. The usual deposition temperature for ZnO is around 400 °C even though higher deposition temperatures produces ZnO of higher crystalline quality. We used an innovative way to directly deposit ZnO on the polymer substrate below 150 °C. This power generator demonstrated a maximum power output of 200 μW. This is the first attempt to use a uniform film of ZnO for energy harvesting. We expect that energy harvested by this device will be able to power wearable sensors.
Modeling Effects of Occupants’ Time-Off Behavior in Buildings on Load Calculation and Energy Modeling
Authors: Pedarla Lakshmi Prasanna , Khazaii Javad
Published: February 2023

The number of people living and working in a building is one of the key inputs to the load calculation and energy modeling software for buildings HVAC system design. The number of occupants in a building not only has a considerable effect on the internal load/ energy consumption of the building, but also directly affects the required building quantity of outdoor air. Load associated to the number of occupants and quantity of required outdoor air for these people contributes close to one-third of the total load/ energy consumption of a building [1]. In addition, number of the occupants will affect the associated equipment load/ consumed energy by the people as well. HVAC engineers select the number of the people living and working in the buildings based on the design architect’s intention, type of application, and the engineering standards and guidelines recommendations. Design engineers based on the recommendations of these guidelines, and their own experience/judgement and architect input, set the design value for the number of occupants in the calculating software. As the result of design engineer assumption/ judgement which generally tends to give some diversity allowance for the design number of occupants, the load and energy consumption of the buildings will be reduced uniformly throughout the year depending how much allowance each engineer assumes. In this research authors will use agent-based modeling simulation to model occupants’ behavior when selecting their time on-off hours throughout the year. Using this modeling helps the researchers to evaluate if it is possible to justify engineers’ judgement for uniformly reduction of the number of people and their associated equipment when performing load calculation and energy modeling. The model will also contribute to developing a better occupant scheduling when running load calculation/ energy modeling programs.
Development of Phase-Change Materials with Improved Thermal Properties for Space-Related Applications
Authors: Adegbaye Patrick , Pei Yong , Kabir Mehdi , Sandja Tchamba Herve Cabrel , Yang Bao , Xu Jiajun
Published: February 2023

For spacecraft thermal management systems, it is crucial to diminish the overall mass of onboard thermal storage system and minimize the temperature fluctuations when the environmental temperature changes drastically. Since there is no atmosphere in outer space, heat can only be rejected to space using radiation (e.g., radiators). The heat sink conditions, and the heating power subjected to be rejected vary continuously at the orbiting stage of the spacecraft. Without thermal storage capability, the radiator is required to be large enough to release the highest power at the hottest of the heat sink. Possessing a large latent heat of fusion, PCMs can store an enormous amount of thermal energy within a small volume, which makes them ideal for spacecraft thermal management systems. The heating power required to be rejected as well as the heat sink conditions vary steadily at the orbiting stage of spacecraft. Without thermal storage capability, the radiator is needed to be large enough to release the highest power at the hottest of the heat sink. By engaging and integrating phase-change materials (PCMs) into a passive two-phase heat exchanger, the radiator can be designed and sized for the average rather than the maximum power.

This study aims to develop phase-change materials (PCMs) using nanostructured graphitic foams to enhance thermal conductivity of PCMs for improved thermal response in thermal storage applications. In the present study, the correlation of additive’s mass concentration and particle size on the thermal properties of PCM mixtures are investigated experimentally and numerically. Introduction of conductivity enhancing additives into the base PCMs will negatively affect the latent heat of fusion while improving thermal conductivity. Analytical and experimental results for latent heat of fusion are shown to be in good agreement, indicating that as mass concentration of graphitic foam (i.e., C-Foam) increases, the latent heat of PCM decreases consistently. The simulation results also reveal that a small fraction of porous C-Foam additives can significantly enhance thermal conductivity of the base PCM.
Design and Implementation of Biohybrid Diaphragm Pump to Be Driven by Cardio Myocytes
Authors: Artmann Lucas , Ameres Valentin , Wund Emmy , Lueth Tim C.
Published: February 2023

In this report we introduce the design and prototype implementation of a bio hybrid pump driven by cardiac muscle tissue to supply other biological actuators in a larger bio hybrid robotic system sufficiently with nutrition media. Recently introduced bio hybrid pumps are analyzed and compared. On this basis a diaphragm pump design is chosen as physical principal and a functional prototype is designed. The derived requirements regarding the flowrates and long-term stability are verified with mechanical tests of the implemented prototype. The pump itself will consist of a body, an actuating membrane (to carry future muscle cells), a cylindrical spacer block, a returning diaphragm and the retaining ring. During operation the flow direction is implemented by two check valves. Our mechanical verification results show a flowrate of 14.2 ml/min with an activation frequency of 1 Hz. For the displacement of the returning diaphragm a required force of 0.58 N is determined. This is well within the capabilities of cardio myocytes which are in the range of 2 to 5 nN/μm2 and therefore could generate 0.63 to 1.57 N given the area of the 40 mm diameter membrane.
Effect of Autoclave Cure Temperature, Pressure, and Time on the Glass Transition Temperature and the Degree of Cure of Epoxy Film Adhesive Joints
Authors: Nassar Sayed A. , Jagatap Shraddha , Hirulkar Nitesh
Published: February 2023

This study investigates the effect of autoclave curing variables on the glass transition temperature of and the degree of cure and strength of epoxy film adhesive single lap joints (SLJs) under static tensile shear loading. Studied autoclave variables include the cure temperature, cure pressure, temperature, and pressure ramp rates on the glass transition temperature as well as the cure time duration. Test joints are made of Aluminum substrates that are autoclave-bonded using epoxy film adhesive (AF163-2k). For each variable combination of the autoclave process, the corresponding glass transition temperature of cured Epoxy film adhesive is obtained using Dynamic Mechanical Analysis (DMA-Q800). Test data are generated for both baseline joints [uncycled] as well as for joints that have been heat-cycled in an environmental chamber after initial autoclave bonding. Results show a strong correlation between the autoclave process variable combinations and the corresponding glass transition temperature bond strength, and the failure mode of test joints.
Combustion and Vaporization of Deformable Fuel Droplets Using Direct Numerical Simulation
Authors: Setiya Meha , Palmore John A.
Published: February 2023

This study focuses on the effects on evaporation and combustion of a single component jet fuel surrogate. Due to an imbalance in the surface tension and aerodynamic forces, the large droplets have a tendency to deform. The effect of the shape change of a droplet on its combustion is studied at a moderate Reynolds number by varying the Weber number. A simplified chemical reaction mechanism for hydrocarbons is used for the combustion of the droplet. Through this study, the effect of different Weber numbers is investigated on the total evaporation rate, further on droplet combustion, and the flame shape. The results of this study show an increase of 2% increase in total evaporation rate (m) for higher Weber number We = 12 as compared to low Weber number (We = 1) case. Though, the increase in m is small, the results show a net positive effect of Weber number on the total evaporation. In terms of combustion, the combustion process stays unaffected by the droplet shape as the mass burning rate is nearly the same for low as well as high Weber number. The potential reasoning could be that the interaction between the flow and geometry of droplet in two dimensions (2-D) is insufficient to explain the physics. Moreover, it is possible that the reaction rate which is faster in nature is dominating over the evaporation rate. Such observations require more detailed work in three dimensions (3-D) for future.
Evaluation of Weld Quality Through Non-Destructive Testing and Weld Property Analysis of Friction Stir Welded AA2014 Under Submerged Condition
Authors: Velukkudi Santhanam Senthil Kumar , Selvaraju Harinivas , Augustine Michael Duke Mystica
Published: February 2023

Aluminum Alloy2014 is one of the strongest aluminum alloys and is a copper-based alloy that has a high strength-to-weight ratio. Poor corrosion resistance, porosity, cracking, and element loss makes the alloy difficult to weld in gas and arc welding techniques. To overcome these difficulties, the most suitable method for joining aluminum alloy2014 is Friction Stir Welding. Due to its high strength, aluminum alloy2014 is joined using Friction Stir Welding in aerospace industries in fuel tanks of spaceships and other automotive industries in making complex shapes. In the current study, aluminum alloy2014 alloy is friction stir welded under submerged conditions employing graphene nanofluid. The welding was carried out under the optimized process parameter of tool rotational speed 1200 rpm and a transverse speed of 72 mm/min. A hardened square pin tool of length 5.5 mm and diameter of 4 mm is used for joining the aluminum alloy2014. The graphene nanofluid is developed using the two-step method constituting water as the base fluid. Water is suspended with 0.5 wt% of graphene nanoparticles. In this investigation, Radiography analysis, surface roughness, microhardness, tensile behavior and Facture analysis under two different conditions, normal welding and submerged welding was determined.
Design a Low Specific Speed Dry Pit Solids Handling Pump With Pure 3-D Computational Fluid Dynamics Virtual Testing
Authors: Ali Azfar , Zhou Zhuoyu
Published: February 2023

A relatively low specific speed dry pit solids handling pump was designed from scratch with pure 3D CFD virtual testing. In-house codes were used to provide preliminary design of the impeller, volute, etc. The 3D CFD tool Simerics-MP+ was employed for improvement of the design to achieve the desired pump performance. The virtual tests covered a wide range of flowrates from 40% to 130% of the best efficiency point (BEP). Final physical testing shows the CFD predictions are in good agreement with the measurements.
Microfluidic Devices for Isolating and Releasing Disseminated Tumor Cells in Bone Marrow
Authors: Le Minh-Chau N. , Chen Dongjiang , Smith Kierstin A. , Tran David D. , Fan Z. Hugh
Published: February 2023

Triple-negative breast cancer (TNBC) is a highly aggressive and lethal subtype of breast cancer. Many TNBC patients have significant risks of developing life-threatening metastases even after receiving successful neoadjuvant treatment. One reason for this high treatment failure rate is the presence of treatment-resisting disseminated tumor cells (DTCs) in the bone marrow (BM). DTCs have an extremely low occurrence of 1 per 106−107 nucleated BM cells. Hence, one challenge in studying DTCs is to enrich for these rare cells while retaining their viability for further molecular analysis. Microfluidic technology has become a promising solution by offering high detection sensitivity, low reagent consumption, and simple operation. Our project demonstrates the use of the immunoaffinity-based geometrically enhanced mixing (GEM) microfluidic device to efficiently capture TNBC cells in BM aspirates and safely release them for future single-cell ribonucleic acid (RNA) sequencing. Using anti-EGFR (epidermal growth factor receptor) antibodies as the capture agent, the GEM offers a capture efficiency of ∼70%. By combining the cell-dissociation chemical trypsin with mechanical impulses, the release efficiency reaches ∼95% while maintaining viability and morphology similar to that of TNBC cells in culture. This work has the potential to contribute towards the future identification of TNBC therapeutic targets.
Development of 3d Printed Soft Pneumatic Hand Motion Sensors
Authors: Papendorp Sky , Iyun Olukayode , Schneider Christian , Tekes Ayse , Ashuri Turaj , Amiri Moghadam Amir Ali
Published: February 2023

This paper reports on the design, fabrication, and evaluation of a novel 3D printed vacuum based soft sensor and its application as hand motion sensor. Soft sensors are an integral part of soft robotics as an emerging field of science that enables safe and easy human to machine interaction. The conventional sensors used to interface with humans in robotic systems are mechanically incompliant. Because of this mechanical compliance mismatch, these sensors cause unsafe interactions with humans. Recent advancements in 3D printing technology have allowed fabrication of complex geometries with soft polymers, perfect for more delicate and user-friendly sensors. While the existing soft pneumatic sensors work based on the positive pressure due to deformation, the proposed sensor in this work works based on vacuum due to deformation. In comparison with the similar positive pressure sensor, our vacuum-based sensor is much softer and has minimum interference with hand motion. Finite element analysis (FEA) is used to analyze the design. Also, a kinematic model of the hand is developed using Matlab to visualize the hand motion based on the sensor data. This could show the potential application of the soft hand motion sensor in virtual reality and telehealth.
A Numerical Investigation to Compare Point Cloud and STL-Based Toolpath Strategies for 5-Axis Incremental Sheet Forming
Authors: Gupta Ayushi , Nagargoje Aniket , Dubey Abhay Kumar , Tandon Puneet
Published: February 2023

To address the difficulties faced by the existing 3-axis incremental sheet forming (ISF) processes, toolpaths of 5-axis incremental sheet forming were developed to form the components with features having forming angles greater than 90°. This paper compares the STL and point cloud-based methodologies for the toolpaths generated for 5 axes incremental sheet forming. The STL models are used in the existing 5-axis toolpath techniques to determine the point normal at a contact point and hence the tool posture angles. However, there are several drawbacks associated with this approach of using STL models. Thus, a point cloud-based posture calculation strategy is proposed in this work. It was observed that the proposed approach performs better than the STL-based strategy in terms of computing efficiency. Numerical simulations were performed to validate the approach utilizing the toolpaths generated by both strategies. The simulation of the ISF process was performed to determine the feasibility of the 5-axis incremental sheet forming toolpath. Finite element simulations were performed using the shell elements for the geometry with the curvature of the wall greater than 90°. Results based on geometrical accuracy are compared to understand the differences between the two strategies.
The Real-Time Human Reliability Detection System Based on Ship Bridge Videos
Authors: Wang Shuoping , Xiao Youan , Wang Tengfei , Li Zhuo
Published: February 2023

Human reliability analysis in assessment of ship collision risk has always been a concern for shipping practitioners. The risk of ship collision is largely related to the driving state of crew. At the same time, although surveillance cameras have been deployed in key locations such as ship bridge on most of the current operating ships, the monitoring information is only used as evidence for daily evaluation or responsibility determination after an accident, further values are not discovered. How to make full use of existing ship bridge video resources to assess the realtime state of crew, and then assess the risk of collisions, is of great significance and academic value.

Therefore, this paper proposes a real-time human reliability detection system based on ship bridge videos. Object detection model trained on COCO[1] dataset using Faster-RCNN [2] algorithm and spatio-temporal action detection model trained on AVA [3] dataset using SlowFast [4] algorithm are used to perform video understanding work on ship bridge videos, obtaining the actions of crew and corresponding probabilities. This paper introduces performance impact factors (PIFs) and Information, Decision and Action in a Crew content cognitive (IDAC) model to build a three-layer mapping model which clarifies how to use the results of video understanding work to calculate relevant PIF scores and explain the impact of the state of crew on various processes in IDAC model.
Topology Optimization Through Deep Neural Network for Different Mechanical and Thermomechanical Problems
Authors: Shishir Md. Imrul Reza , Tabarraei Alireza
Published: February 2023

In this present work, a neural network (NN) is trained to deal with the optimization process of topology optimization and generate optimized structures. The NN’s activation functions are used to represent the popular Solid Isotropic Material with Penalization (SIMP) density field. Fourier projection based length scale control technique has been implemented to govern the minimum and maximum feature length in the optimized domain for manufacturability. And high-performance automatic differentiation (AD) library JAX has been used to build an end-to-end differentiable NN model. We demonstrate the application of this framework by solving several mechanical and thermomechanical compliance minimization problems. The results show that optimized designs obtained from the proposed NN based approach are comparable with the current mathematical programming based optimization approach.
Using Granular Jamming and a Parallel Compliant Mechanism to Provide a Rapidly Deployable, Custom-Fitted Cervical Collar
Authors: Herke Patrick , Kumar Abhishek , Gilbert Hunter B.
Published: February 2023

Cervical collars are medical devices commonly used to restrict motion of the cervical spine after trauma or surgical intervention. Improvements to the kinematic adjustability of collars and the rigidity of the contact surface between the patient’s body and the collar would result in better restriction of motion while maintaining comfort and fit. This paper reports on the initial design and prototyping of a new design concept for cervical collars consisting of pouches of granular material along the inside of two rings which are of similar geometry to the neck. The rings are connected by six adjustable length struts, analogous to the classical Stewart-Gough platform. Granular jamming is a reversible process in which a bladder containing a granular material, such as coffee grounds, becomes stiff when a vacuum is drawn on it. Thus, the pouches allow for a moldable interface with the neck with adjustable rigidity. The 3D printed rings are designed to accommodate the geometry of individual wearers by flexure hinges approximating a continuously deformable structure. The geometry of the rings was selected by surface modeling of the body geometry followed by extraction of coordinate curves and flattening. The struts provide patient specific adjustments for neck height and variance in head shape.
Nonlinear Dynamics Simulation of Stress Concentration Factor of Pear Cam and Roller Follower Mechanism With Clearance
Authors: Yousuf Louay S.
Published: February 2023

The effect of stress concentration factor on the nonlinear dynamics phenomenon of the follower is studied at different internal distance of the follower guides from inside (I.D.) and different cam speeds (N). The stress concentration factor is examined at the contact point and around the square grooving key. The contact between the cam and the follower and between the follower and its guides are considered using SolidWork program. Three different involutes’ profiles of the pear cam are used to select the optimum cam profile. Phase-plane diagram is used to detect the periodic and non-periodic motions over times. Moreover, the dynamic tool of Wolf algorithm code is used to calculate the local Lyapunov exponent against number of samples. The overshoot of the transient response of local Lyapunov exponent parameter is done at different cam speeds and different follower guides’ clearances. Photo-elastic device is used to check the value of stress concentration factor experimentally. Multi spring-damper-mass model is used on the follower stem to reduce the contact stress at the contact point and around the square grooving key.
Nonlinear Dynamics Simulation of Globoidal Cam and Roller Follower Mechanism With Clearanance Using Different Material Properties
Authors: Yousuf Louay S.
Published: February 2023

The effect of contact different material properties for globoidal cam and roller follower system on the nonlinear dynamics phenomenon is investigated at different cam speeds and different follower guides’ clearances. The contact between the cam and the follower and between the follower and its guides are considered at different contact conditions. The optimal contact condition is selected based on the value of local Lyapunov exponent parameter. The impact and friction are considered in SolidWorks program based on the value of sliding contact velocity and kinetic coefficient of friction. The contact condition is steel dry, steel greasy, nylon, acrylic, aluminum dry, and aluminum greasy. The nonlinear dynamics and chaos is detected using phase-plane diagram and Poincare’ map. The trend of the nonlinear response of the follower displacement is discussed at different contact conditions. The more black dots in Poincare’ maps, the more detachment heights between the cam and the follower since the black dots are stationed around one area inside Poincare’ map. In phase-plane diagram, the follower displacement-velocity diverges with no limit of spiral cycles which gives indication that the motion is non-periodic and chaos.
The Analysis of Interaction Between Reflected Shock Wave and Boundary Layers in a Shock Tube
Authors: Olaoke Abdulmumin O. , Molki Majid
Published: February 2023

This study is a computational investigation of the interference between a reflected shock wave and the wall boundary layers formed by gas flow in a shock tube. Two gases, namely, Argon and Helium, are examined as the working fluid in each case at different pressure ratios. The present computations consider the viscous effects and implement turbulence through the Spalart-Allmaras model. The study observes and analyzes the non-ideal transient behavior in the shock tube. It also examines thermal effects and the shock bifurcation for two gases at different pressure ratios of 10 and 100. The present simulations explain the temperature distribution behind the bifurcated shock waves. The results show that the range of disturbance formation for each gas varies with pressure ratio. The outcomes of this study agree well with theoretical methods, which assume uniformity behind the reflected shock wave under ideal conditions. However, consistent with the past studies, this investigation confirms that reflected shock waves interact with the wall boundary layers, and bifurcation occurs. We noticed the gas pressure ratio plays a significant contribution to the tendency and strength of the bifurcation. The higher the pressure ratio, the faster the shock wave traveled, and the quicker the relative bifurcated foot velocities increased with the Mach number at that region. This research contributes and sheds light on the role of gas type and other parameters on the nature of the interaction between a traveling shock wave and a thin boundary layer. This investigation’s findings will benefit the supersonic compressible flow applications and experiments.
Identification of Mechanical Fault of Induction Motor by Combining Lyapunov Exponent and Random Forest Algorithm
Authors: Liu Yan , Geng Jincheng , Li Yuchen , He Yiming
Published: February 2023

In this paper, a scheme by combining Lyapunov exponent and random forest algorithm for mechanical fault identification of induction motor is proposed. During the implementation of the scheme, the severity of pedestal looseness is identified. First, operating states of motors are simulated in an experimental platform. Vibration signals are measured and the evolution of signal waveform are revealed. Subsequently, for vibration signals of different input frequencies or different number of pedestal loose bolts, Lyapunov exponential spectrums are calculated by BBA algorithm. Features extracted from Lyapunov exponential spectrums, such as largest Lyapunov exponent and Kolmogorov entropy, are utilized to demonstrate the chaotic characteristics of signals. At last, extracted features are fed into random forest model for the fault classification. The feasibility of this scheme is validated by accuracy of fault recognition greater than 90%. Several groups of experimental results indicate that proposed scheme has high effectiveness and generalization performance.
Application of Second-Order Boundary Conditions in the Vibrations of Beams With Attached Lumped Mass Under Axial Force
Authors: Hassanpour Pezhman
Published: February 2023

This paper addresses the exact solution of a beam’s free vibrations with a concentrated mass within its intervals when the beam undergoes an axial loading. The Euler-Bernoulli beam theory is used as the basis of the model of the beam. This problem has been extensively studied before in the literature. The main contribution of this paper is in its novel approach to treating the effect of the concentrated mass and solving the resulting governing equation of motion. The effect of the concentrated mass is incorporated into the governing partial differential equation (PDE), rather than being treated as a boundary condition. To this end, the effect of a distributed transverse force, a distributed moment, and axial loading is included in the governing PDE. Then, the properties of Dirac’s delta function is used to represent the attached concentrated mass as a displacement-dependent concentrated transverse force. As a results, the PDE has the delta function as a coefficient of one of its terms. This type of equations are traditionally solved in frequency domain using Laplace transforms. In this paper, the technique to solve this PDE in time domain is presented. It has been demonstrated that this technique intrinsically leads to the application of the second-order theory. The exact natural frequencies and mode shapes of vibration of the system are determined by solving the PDE for free vibrations.
Optical and Heat Transfer Performance of Conical Receivers for Desalination Application
Authors: Soanker Abhinay , Oztekin Alparslan
Published: February 2023

This study involves numerical analyses of a 7.5 m parabolic dish concentrator for membrane distillation desalination applications. Optical and heat transfer performance of conical receivers with an angle of 45°, 75°, and a spiral receiver was investigated. Receiver designs considered here have helical coil receivers that carry heat transfer fluid (HTF). The optical performance of these three conical receivers was studied based on the distance of receivers from the focal point. This study considered three distances: 0.06m, 0.12m, and 0.18m. Ray tracing simulation has been carried out to obtain the receiver’s radiation heat flux distribution data. It is observed that the 45° conical receiver yields the highest optical efficiency, 82%, when the receiver is placed 0.12m from the focal point.

Heat flux data obtained during the optical simulations have been utilized as a boundary condition. In addition, numerical simulations are carried out to evaluate the heat transfer performance of the 45° conical receiver. The study included Reynolds numbers of 1,917, 10,222, and 19,167. The outlet temperatures have been examined.
Ontology-Based Framework for Knowledge-Based Lifecycle Management of Product Information
Authors: Failla Lorenzo , Rossoni Marco , Vallesi Michele , Colombo Giorgio
Published: February 2023

One of the major barriers to close the gaps between the academic paradigm of Product Lifecycle Management (PLM) and the actual potentialities offered by modern PLM implementations in industry is represented by the inherent difficulty in the management of product information structured over a formalized product-related knowledge. This is especially true for complex, highly customized and engineer-to-order products. The amount, the complexity and the variability of the information throughout the lifecycle makes the Product Data Management capabilities inadequate to realize the required level of accessibility. Ontologies and Semantic Web Technologies are a promising solution in addressing the aforementioned challenges relevant to PLM. Despite that, ontologies implementations in real industrial applications remain very limited in number and, in any case, either are restricted to specific areas or tackle the issue from a too general point of view.

The paper aims to present a generalized approach to structure a product knowledge domain over a general-purpose, agnostic “base” ontology. It has been developed on top of formal model taken from literature, where the knowledge relative to a complex, highly customized and engineer-to-order (ETO) product from Oil & Gas Turbomachinery industry was formalized in an OWL-DL ontology enriched with SWRL rules and reasoning capabilities. To facilitates the interaction and the validation with the formal model, a Graphical User Interface (GUI) has been implemented. It enables the penetration of reasoning-enabled ontologies within industrial mindsets and forms the foundations for future integration of the generated product information layer within industrial PLM ecosystems. Within this context, IT asset used to realize the presented proof-of-concept is described and major challenges encountered during the realization and the way they have been tackled are discussed, together with strengths and limitations associated to the approach.