Eberhard Haug

Human Models for Crash and Impact Simulation

Publisher Summary This chapter discusses the application of computational impact biomechanics to the consequences of real world passenger car accidents on human occupants, using computer models in numerical simulations with industrial crash codes. The corresponding developments are illustrated on the subject of safety simulations of human passenger car occupants. With some adaptations, the developed models apply equally well to the simulation of pedestrian accidents and to the design for occupant safety of motorbikes, trucks, railway vehicles, airborne vehicles, seagoing vessels and more. The human models elaborated in the chapter belong to the class of finite element models. They can be adapted, specialized and packaged for other industrial applications in human ergonomics and comfort analysis and design, in situations where humans operate at their work place, as military combatants, or in sports and leisure activities and more. In the medical field, biomechanical human models can serve as a basis for the simulation and design of orthopedic prostheses, for bone fracture planning, physical rehabilitation analysis, the simulation of blood flow, artificial blood vessels, artificial heart valves, bypass operations, and heart muscle activity, and virtual organ surgery.

Improvement of numerical ankle/foot model: modeling of deformable bone

A new modeling approach of the principal bones of the ankle/foot model is described. The most often injured ankle/foot bones in vehicle accidents are the tarsal bones and the fibular and tibial malleoli. These bones are modeled as deformable bodies to simulate the bone and soft tissue injuries. The deformability of the bone ultimately permits to assess the damage behavior of the main parts of the ankle/foot complex during an impact loading. The localization of the maximum stress allows to identify the regions where injury can occur. Language: en

A NUMERICAL MODEL OF THE HUMAN ANKLE/FOOT UNDER IMPACT LOADING IN INVERSION AND EVERSION

A numerical model of the human ankle/foot under impact loading is presented. This model is validated at different levels of energy by simulating the principal movements of inversion and eversion in car crash. The gross kinematics of the model is correlated with experimental tests. At a local level, the primary relative motions of the bones during the inversion and the eversion is found. Language: en

Human body modeling for riding comfort simulation

In order to assess the seating and riding comfort design of a vehicle seat in an objective manner, finite element occupant models with anatomically precise features have been developed. The human body models are incorporated into Pam-Comfort, a tool for automotive seat design and analysis, as parts of occupant surrogates that also include HPM I and II. In this paper, the detailed process of FE human body modeling including an effort on the implementation of new anthropometry will be introduced. The validation of some features of human body models in seating and riding comfort simulation against human experiments will be also presented.

Real-time micro-modelling of a million pedestrians

Purpose – The purpose of this paper is to develop a first-principles model for the simulation of pedestrian flows and crowd dynamics capable of computing the movement of a million pedestrians in real-time in order to assess the potential safety hazards and operational performance at events where many individuals are gathered. Examples of such situations are sport and music events, cinemas and theatres, museums, conference centres, places of pilgrimage and worship, street demonstrations, emergency evacuation during natural disasters. Design/methodology/approach – The model is based on a series of forces, such as: will forces (the desire to reach a place at a certain time), pedestrian collision avoidance forces, obstacle/wall avoidance forces; pedestrian contact forces, and obstacle/wall contact forces. In order to allow for general geometries a so-called background triangulation is used to carry all geographic information. At any given time the location of any given pedestrian is updated on this mesh. The ...

Modelling of ergonomics and muscular comfort

Commercially available software packages permit to position human models of various geometries in practical scenarios while respecting the anatomical constraints of the skeletal joints and of the bulk of the bodies. Beyond such features, the PAM-ComfortTM software has been conceived to provide direct access to the muscular forces needed by humans to perform physical actions where muscle force is required. The PAM-ComfortTM human models are made of multi-body linked anatomical skeletons, equipped with finite elements of the relevant skeletal muscles. The hyper-static problem of determination of muscle forces is solved by optimisation techniques. Voluntary stiffening of muscles can be added to the basic contraction levels needed to perform a specific task. The calculated muscle forces obey Hills model. The model and software have been applied in several interesting scenarios of various fields of application, such as car industry, handling of equipment and sports activities.

BUTTERFLY-EFFECT FOR MASSIVELY SEPARATED FLOWS

Purpose – During a routine benchmarking and scalability study of CFD codes for typical large-scale wind engineering runs, it was observed that the resulting loads for buildings varied considerably with the number of parallel processors employed. The differences remained very small at the beginning of a typical run, and then grew progressively to a state of total dissimilitude. A “butterfly-effect” for such flows was suspected and later confirmed. The paper aims to discuss these issues. Design/methodology/approach – A series of numerical experiments was conducted for massively separated flows. The same geometry – a cube in front of an umbrella – was used to obtain the flowfields using different grids, different numbers of domains/processors, slightly different inflow conditions and different codes. Findings – In all of these cases the differences remained very small at the beginning of a typical run, they then grew progressively to a state of total dissimilitude. While the mean and maximum loads remained s...