AHFE Open AccessAdvances in Applied Digital Human Modeling
Editors: Vincent Duffy
Topics: Digital Human Modeling and Applied Optimization
Publication Date: 2020
ISBN: 978-1-4951-2094-7
DOI: 10.54941/ahfe100405
Articles
Using Santos DHM to Design the Working Environment for Sonographers in Order to Minimize the Risks of Musculoskeletal Disorders and to Satisfy the Clinical Recommendations
The percentage of sonographers reporting consequences of pain and discomfort is close to 80% and the Society of Diagnostic Medical Sonography demonstrates that sonographers, on average, experience pain or Musculoskeletal disorders within 5 years of entering the profession. Digital Human Models (DHM) can be an essential tools, supporting the definition of a correct medical environment to perform Sonography in response to the regulatory aspects that standardize the Health Care design and in setting up the ergonomics requirements. The methodology proposed to perform an optimal setting of the workspace considers the different aspects of a diagnostic Ultrasound (US) examination room in a clinical setting: sonographer's seating and examination bed, US system and probe. Vascular and Abdominal applications were considered. The aim of this study is to present an example of how an Advanced DHM can support the design of the working environment for sonographers in order to minimize the risks of muscle-skeletal disorders and to satisfy the clinical recommendations. Results were compared with data presented in previous studies about ergonomics in professional sonography and they demonstrate to be coherent with the plan for an ideal set-up.
M. Mazzolaa, L. Forzonib, S. D’Onofriob, C.E. Standolia, G. Andreonia
Open Access
Article
Conference Proceedings
Using MRI-Derived Spinal Geometry to Compute Back Compressive Stress (BCS): a New Measure of Low Back Pain Risk
Back compressive force (BCF) is a commonly used surrogate for the risk of developing low back pain. Point force estimates of spinal loading have been shown to predict low back pain in epidemiological studies. However, they are an imperfect measure and can over- or under-estimate risk, particularly for very large or small individuals. A logical means to normalize risk over a varied population is to convert these forces to stresses (force/unit area). To achieve this, Magnetic Resonance Imaging (MRI) scans were used to provide area measurements for the intervertebral discs and vertebral bodies of the lumbar region (L3/L4, L4/L5, & L5/S1 segments). Various regression models were explored based on individual subject gross anthropometry. These models allow for the estimation of intervertebral disc (IVD) size using easily measured anthropometric characteristics such as height and gender. Converting the BCF to a back compressive stress (BCS) normalizes and personalizes risk estimates for subjects of varying sizes. Back compressive force data from a previous study was converted to back compressive stress to determine if risk estimates could be improved. Using peak BCF with a cut point of 3400 N (~770 lbs) yielded an odds ratio of 2.76 (1.2-6.6) to predict jobs with injuries and discomfort. Using BCS with a cut point of 280 N/cm2, which corresponds to 3400 N load applied to a 50th percentile female L5/S1 IVD area, improved the odds ratio to 5.78 (1.8-18.4). Normalizing for the size of a subject’s IVD shows great promise for improving the predictive abilities of biomechanical assessment methods.
Richard Sesek, Ruoliang Tang, Celal Güngör, Sean Gallagher
Open Access
Article
Conference Proceedings
The Quest to Validate Human Motion for Digital Ergonomic Assessment –Biomechanical Studies to Improve the Human-Like Behavior of the Human Model “EMA”
Modern digital human simulation tools try to generate motions over an decreased number of input information to pass the method of step-by-step motion generation as it has been common until now. A key feature of EMA is the self-initiated motion generation, which decreases the effort for users in simulation preparation and increases the validity of simulation results in terms of realistic motion trajectories and biomechanical correctness. EMA has been designed for the simulation of human work activities in industrial production. EMA is already capable of reproducing most of common work-related activities, but there is still a need to improve its performance for some specific tasks. With the advancing number of automatically generated movement, the responsibility of the software to produce valid and reliable movement rises to a new level. Furthermore the necessity of valid motor behavior is based on the requirement of a correct assessment of work time and ergonomics in the simulation. Such assessment functions are already implemented using ‘state-of-the-art’ methods like MTM (Methods Time Measurement) for time analysis and EAWS (Ergonomic Assessment Worksheet) for ergonomics risk evaluation. In order to improve the quality of the ergonomic, time-related and visual simulation results, several studies have recently been carried out. The results of these studies show a large range in variation and complexity leading to the question, how to transfer information gained with scientific studies into explicit implementations for digital human modeling software.
Dan Gläser, Lars Fritzsche, Sebastian Bauer, Wolfgang Leidholdt
Open Access
Article
Conference Proceedings
Basic Method for Handling Trivariate Normal Distributions in Case Definition for Design and Human Simulation
The paper describes a basic approach for the establishment of representative test persons when performing accommodation analyses and wanting to simultaneously consider normal variation in three variables. The main application is for defining a number of different manikins when performing ergonomics simulations for boundary case based accommodation analyses using digital human modelling tools. The method is also applicable when wanting to select representative people to be involved in user trials or to get direct design data. One objective is that the proposed method shall support inclusive design in that it is easy to adopt by non-experts in multivariate accommodation analyses, and accordingly reduce the amount of unsuitable univariate accommodation analyses. The paper introduces the reader to the area of interest, making links to previous research and current problems. The approach for the development of the basic method is explained. The confidence ellipse method is used for defining appropriate boundary manikins according to three selected key variables and desired accommodation level. The paper includes two examples that illustrate the method and compare the method to an alternative method.
Dan Högberga, Erik Brolinab, Lars Hansonbc
Open Access
Article
Conference Proceedings
Assessing the Precision of Anthropometric Measurements: A Six Sigma Approach
Anthropometrics is the measurement of dimensions of the human body defined between fixed anatomical landmarks (). The human body however does not generally lend itself to simple measurement as the limits or position of anatomical landmarks can often be open to interpretation. Given that effective anthropometric practices are dependent on the validity of the anthropometric data, it is critical that anthropometrists have confidence in the data they use. This paper discusses existing practices in determining anthropometric measurement error and introduces the Six Sigma technique, Gauge Repeatability & Reproducibility, to the discipline of anthropometry.
Dermot Hale, Enda F. Fallon
Open Access
Article
Conference Proceedings
Interactive Simulation and Ergonomics Assessment of Manual Work With EMA – Applications in Product Development and Production Planning
The software tool EMA (“Editor for Manual Work Activities”) facilitates digital production planning and ergonomics assessment by providing a more efficient and accurate approach to 3D human simulation. EMA uses a modular system for describing human work activities based on a pre-defined library of “complex operations”, which allows the generation and simulation of human movements with highly-automated algorithms. Moreover, EMA includes standard tools for the assessment of ergonomic strains (EAWS – “Ergonomic Assessment Worksheet”) and production time (MTM – “Methods Time Measurement”). After introducing some basic analysis functions of EMA and their typical use cases, this paper presents an evaluation study that examines the validity of EMA ergonomic evaluations in comparison to paper-pencil-assessments with EAWS. Moreover, this paper shows several use cases of the EMA software application in automotive and aviation industry. These applications illustrate that EMA considerably reduces the effort for preparing human simulations and enables the user to analyze ergonomic conditions (body posture, action forces, manual load handling) and productivity (e.g., walk ways) very thoroughly.
Lars Fritzsche, Ricardo Schönherr, Benjamin Illmann
Open Access
Article
Conference Proceedings
Influence of Fingertip Anthropometry and Anatomy on Mechanical Loads During Grasping
Many researchers have investigated the mechanical loads during hand tool use to increase the user performance, satisfaction, and lower the risk of acute and cumulative trauma disorders. While grasping, the mechanical loads are directly transferred to the hand. Rough guidelines of pressure discomfort (PDT) and also pressure-pain threshold (PPT) were provided by previous researchers, where values differ by the subject and the area of the hand. The difference in both limits is between subjects due to the different psychological and physiological factors. In order to understand the physiological aspect of the PDT and PPT difference between subjects, we investigated the influence of the fingertip anthropometry and anatomy on the grasping and the resulting mechanical loads on the fingertip using finite element analysis. Results from the numerical tests have shown significant difference between peak contact pressures as well as the contact pressure distribution between different fingertips. It has been shown that based only on anthropometry the peak contact pressure values and contact pressure distribution cannot be predicted, since geometry of the anatomical structures, especially the bone has significantly higher influence on the peak contact pressure and contact pressure distribution during grasping.
Gregor Harih, Jasmin Kaljun, Bojan Dolšak
Open Access
Article
Conference Proceedings
Human Factors Modeling fromWearable Sensed Data forEvacuation based Simulation Scenarios
The design and the evaluation of evacuation systems are crucial to guarantee successful responses after an incident. Recent results are presented that target to significantly improve evacuation simulation by parameterizing the human agents’ behavior with information on human factors about stress, perception and decision making. In particular, the single person’s behavior in its specific situational context is investigated in the frame of its embodied decision making. For this purpose, users were equipped with wearable sensors that capture information about the environment, the psychophysiological status of the user, and its viewing (eye tracking glasses) and motion behavior. The studies take place during regularly performed evacuation exercises of large business buildings. From the correlation between the multisensory perceptual and psychophysiological data on the one hand, and the automatically sensed and interpreted situational context on the other hand, we will extract a rule base with a set of logical “pre-condition – action” pairs that will parameterize the crowd simulation model.
Lucas Paletta a, Verena Wagner b, K. Wolfgang Kallus b, Helmut Schrom-Feiertag c
Open Access
Article
Conference Proceedings
A New Representational Method of Human Foot Anatomical Landmark and its Application in Foot Posture Data Acquisition
Functions like protection and comfort are essential requirements of the footwear or orthosis. Naturally, the status of foot anatomy features, judged from both inside and skin surface, is of great significance to the effectiveness of the product. In this study, a novel method to estimate the foot anatomy structural deformation from the skin surface in three typical postures is proposed, which can effectively reveal the inner anatomy status without using CT or MRI. Technology of scanning with range sensor is adopted, and it considerably promotes the efficiency of acquisition of the foot texture model. Reverse engineering tools are used to precisely catch the anatomical landmark locations, and the relevant data is shown in the way of comparison.
KaiWei Zhao, Ameersing Luximon, Ganesan Balasankar, CheeKooi Chan
Open Access
Article
Conference Proceedings
The Digital Evaluation of Driver’s Field of View and its Potential Impact on Cyclist Safety
Driver vision from vehicles is a long standing issue. One highly topical scenario includes accidents to vulnerable road users and in particular cyclists, from collisions with large goods vehicles (LGVs). In many of these cases driver vision is a potential causal factor in the occurrence of the accident. This paper presents research performed into the evaluation of driver vision, funded by the UK Department for Transport. To support the research, a 3D volumetric assessment technique was developed in the SAMMIE digital human modelling system. This highly visual technique provides an indication of the visible volumes of space around a vehicle and any blind spots. Vision was evaluated for a range of vehicle types from cars through to LGVs. To investigate the potential casual effects of vision in accidents and specifically those involving cyclists, scenarios were identified from UK Police accident data. These scenarios were then modelled and evaluated digitally. The results highlight that blind spots exist on many vehicles and for all driver sizes. Many of these blind spots can be countered by a change in posture of the driver. However, the most significant blind spot was found on Category N3 LGVs to the near-side of the vehicle. The research was also instrumental in a change to the EU Regulation 46 to remove the blind spot from future LGVs.
Russell Marshall, Steve Summerskill, Sharon Cook
Open Access
Article
Conference Proceedings
Special Computational Gas Flow Simulation Methods for Trunkline Network Failures
We consider two new methods for numerical solution of a complete system of partial differential equations describing the flow of a gas mixture in pipeline systems. The first method tracks Lagrangian particles as they move together with the flow of transported fluid. When implementing this method, the flow parameters are found by means of a difference scheme, and the distribution of mass fractions of components and enthalpy of matter along the pipeline, by analyzing the motion of the Lagrangian particles. If we ignore the processes of diffusion, these particles must preserve their composition. The energy equation without diffusion and heat conduction reduces to an ordinary differential equation. The method proposed is free of artificial viscosity, because, for example, when considering the equation of continuity of components, variations in their specific mass fractions at any point in space are related only to physically meaningful processes, namely, to the inflow of “new” particles (with “new" specific mass fractions of the components). The second method includes constructing spline functions along the space and time coordinates of the computational mesh subject to the fulfillment of differential equations at its nodes. The use of splines of high orders of approximation improves the accuracy of modeling.
Sergey Pryalov, Vadim Seleznev
Open Access
Article
Conference Proceedings
Digital Human Model Applied to Training and Education in Sports
The purpose of the study is to present a 3D digital interactive environment that is being developed in a game engine software to work with 3D DHM applied to training and education on Sports. This platform is being developed considering the need to analyze data from the same athletes' movements being repeated in different time or even to compare athletes' movements with different skill levels. The main 3D digital platform advantage is its flexibility to handle motion capture data from different MOCAP systems in order to facilitate kinematic analysis by users of low cost motion capture systems. Another important advantage is its portability that allows it to be used in different hardware platforms, as tablets and cell phones. The 3D platform development followed some specific steps, which make it possible not only to visualize the performed motion but also make the interaction between the user and the 3D character. The first step consists on the automatic reconstruction of the 3D character body segments based on motion capture data. The visual representation has as benefit that reduces noise that may be generated in the process of retargeting the motion capture data to a specific rig and character that differs from the actual bone structure original data. The visual representation is generated based on laser scanning data. This makes the representation to be a precise copy of the original bone position and structure of the athlete' specific movement that is being captured. The second step is to link each bone segment by generating a 3D model with a collision area that is necessary for future interaction with the user. After those steps, the user can select to track and generate data of a specific body segment; to play/pause the athlete movement and to draw graphs of segmental angles, joint angles and angular velocity. This functionality is still under development and test. The first application of the 3D digital platform was the movement analysis of high and low skill level Jiu-Jitsu athletes. This analysis allowed an improvement on the athletes’ performance and skills. In the future the integration between the 3D scanned athlete’s model and a virtual environment will allow to develop a virtual simulator that can be applied to education, training and entertainment.
Carla Guimarães, Maria Cristina Zamberlan, Vitor Balbio, Venetia Santos, Alessandra Paranhos, Flavia Pastura, Gloria Cid
Open Access
Article
Conference Proceedings
Design of a Digital Human Modelling Module for Consideration of Anthropometric Diversity
Digital human modelling (DHM) tools are useful when evaluating human-machine interaction as they enable consideration of anthropometric diversity by facilitating the creation of human models, so called manikins, of different sizes and proportions. This paper presents the design of a module, as part of a DHM tool, made to enable a more holistic approach when defining manikin characteristics. The module is created based on previous user interviews and literature studies on the use of DHM systems and advanced mathematical methods for anthropometric diversity consideration. The module is aimed to support and guide non-expert users while at the same time support effective use and provide appropriate functionality also for expert users. The module acts as a digital guide and supports standardised working procedures when creating manikins to be used in subsequent ergonomics simulations and analyses, and shows a strong visual connection between user interface choices and their response.
Erik Brolinab, Dan Högberga, Lars Hansonbc
Open Access
Article
Conference Proceedings
Investigating the Effectiveness of Priming in Virtual Environments
This paper considers the usefulness and possibility of using virtual environments for the advancement of priming research. First, the background and foundational research and experiments are considered. Next, the benefits and drawbacks of utilizing virtual environments is examined. Finally, the paper considers the potential of utilizing virtual environments in an attempt to replicate the existing studies to further establish the validity of virtual environments in priming research and then the potential of these methods to push the boundaries of the field.
Charles Butler
Open Access
Article
Conference Proceedings
Thermal Human Modeling: A Design Tool for Functional Clothing
Functional and smart clothing has been an up-and-coming products for fashion industry. The human model or mannequin, which is a bridge between customer's physical information and design utilization, has vital importance as primary design tool. The physiological messages of human body may have growing needs for design. The traditional geometric human models (G-model), which convey surface anthropometric data, such as shape, volume and size, may be advanced to functional model. Thermal function is highlighted in this study, based upon an emphasized potential of developing new thermal functional clothing for health enhancement and rehabilitation purpose. After reviewing theoretical basis on thermoregulation and body temperature, as well as the future application in fashion industry, the methodology of developing thermal human model (T-model) is introduced, including experiments, data pre-processing and modeling process. The T-model originated from relatively accurate 3D body scanning data has visualized and quantified skin temperature data obtained from thermographs, which may be adopted to 3D fashion design system, e.g. designing, patternmaking, pattern revision, virtual fitting and grading for functional clothing.
Huang Chao a, Ameersing Luximon a, Kwok-Wing Yeung b
Open Access
Article
Conference Proceedings
A Facial Mask Study for Chinese Female
Facial mask, an essential product for skincare, has become a part of daily life for female population. Existing facial mask design has a lot of misfits including missing regions, corrugation and misplacement. There is a need to build a relationship between a 3D face shape and a 2D mask template. An accurate 3D face model and anthropometric measurements are initial steps to design of masks. 3D surface flattening is a method to generate 2D patterns and is widely used to trim materials in garment and footwear industry. In this study, a manual generation of 2D flat pattern from a set of 3D Chinese female face models was described. Facial mask templates with different sizes and cuts were produced and evaluated. The results revealed that sizing dimensions mainly differed in the width for different face models. In addition, the location and area for eye and mouth regions had a relatively large deviation and therefore it should be paid more attention in the mask design. This study provided more insights into the relationship between 2D flat pattern and 3D face shape. The results were expected as a reference for facial mask design and improve its quality to fit.
Yan Luximon a, Yan Cong b
Open Access
Article
Conference Proceedings
A Study of the Comfort of the Materials for Self-Grown Fashion Creation
There have been increasing attempts for fashion material production to be re-defined towards cost effective, low environmental impact, labour friendly and biodegradable. Among them, biotechnology is believed to be one fine substitute for fashion creation in future. A study is being carried out with an aim to explore futuristic development of fashion design and applications where and when the materials can be grown from natural renewable resources and degradable rather than being designed and produced in the traditional tedious way. This paper reports the investigation of the bacterial cellulose formation process in different concentrations of tea broth and different incubation times. Through the comparison and evaluation of the comfort factors of the materials, the optimal favourable material towards self-grown fashion creation was presented.
Phoebe W. Wang, M.C.F. Ng
Open Access
Article
Conference Proceedings
Biomechanical Model of Bare-Breasts
Sports bras are designed to reduce mammary glands or breast movement during exercises, but there is no standardized, valid and reliable method to evaluate relative three-dimensional (3D) breast movement; and there is no literature to predict the 3D force acting on the breasts during activities. A reliable method is essential to evaluate 3D breast movement and to determine the effective design features of supportive sports bras. This study derived and validated a new Breast Coordinate System (BCS) for investigating 3D breast movement, so as to identify the most effective bra features and to analyze the effects of breast volume and bra strap properties on breast movement, then to develop theoretical models of breast force generated during bare-breasted running. In the light of this, 3D mechanical models have been developed based on a system comprising a mass, springs and dampers. The orthogonal force exerted on the breasts during running was derived. The predicted results of maximum breast force were verified with previous literature. The new methods will contribute to future research on human locomotion and the design of close-fitting garments.
During Running
Open Access
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Conference Proceedings
A Finite Element Mechanical Contact Model of 3D Human Body and a Well-Fitting Bra
This paper presents the methods of developing a finite-element (FE) mechanical contact model to simulate the interaction between human breasts and a well-fitting bra. In the FE model, the human breasts are modelled as hyper-elastic material, and the bra is meshed as elastic beam and shell. The FE contact model between the breasts and the bra is defined as a contact pair. The mathematical formulation describes the strain–stress contact mechanics of the 3D human body and the bra under pre-tension. The simulation results provide a fundamental guideline for the calculation of the force mechanics of any body–garment interaction.
Yiqing Cai a, Winnie Yua, Lihua Chenb
Open Access
Article
Conference Proceedings