scholarly journals Forensic Analysis Of Low Speed Vehicle Collisions

2003 ◽  
Vol 20 (1) ◽  
Author(s):  
John A. DOnofrio
Keyword(s):  
Kinetic Energy ◽  
Forensic Analysis ◽  
The Body ◽  
Conservation Of Energy ◽  
Low Speed ◽  
Stop Sign ◽  
Post Impact ◽  
Energy Dissipated ◽  
Energy Absorbing ◽  
Crash Tests

A Low Speed Collision Is Defined, For The Purpose Of This Paper, As A Collision Between Two Vehicles That Produces No Permanent Damage To The Body Of The Vehicle Except To The Bumper System. The Vehicles Are Equipped With Energy Absorbing Bumpers That Are Rated To A Particular Speed. The Collisions Are, For All Intents And Purposes, In-Line In Nature (Collinear) And Without Post-Impact Rotation. This Definition, While Quite Specific, Covers A Large Number Of Collisions. They Are The Typical Stop Sign, Waiting In Traffic, Parking Lot Type Crash. In The Following Sections I Will Examine How These Vehicles Interact And Respond To Such Collisions By Applying Newtons Laws And The Data From Vehicle Crash Tests. Presented Is Methodology For Reconstructing The Pre-Impact And Post-Impact Speed Of Such Collisions Using The Following Protocol: 1. Compute The Kinetic Energy Dissipated In The Collision From The Characteristics Of The Vehicles And Their Bumpers As Revealed In Crash Tests. 2. Use Conservation Of Energy And Damage Relationships To Determine The Pre-Collision Kinetic Energy And Closing Speed Of The Two-Vehicle System. 3. Use Conservation Of Linear Momentum To Calculate The Post-Collision Speed And Delta-V Of The Two Vehicles. This Method Uses The Strict Application Of Newtons Laws And Treats Both Vehicles As A System.

scholarly journals Methods for absorbing kinetic energy with consideration of delay limit value

2021 ◽  
Vol 334 ◽  
pp. 01006
Author(s):  
Jarosław Rajczyk ◽  
Marlena Rajczyk ◽  
Jarosław Kalinowski ◽  
Budownictwa Wydział
Keyword(s):  
Kinetic Energy ◽  
Energy Absorption ◽  
The Body ◽  
Limit Value ◽  
Energy Absorbers ◽  
Energy Absorbing

In this paper the potential of kinetic energy absorption by means of energy absorbing and storing mechanisms was discussed. The use of energy absorbers is intended to reduce the maximum working forces when stopping the body.

scholarly journals Simulation of a Dummy Crash Test in ADAMS

2022 ◽  
Vol 24 (1) ◽  
pp. B20-B28
Author(s):  
Marek Jaśkiewicz ◽  
Damian Frej ◽  
Miloš Poliak
Keyword(s):  
Design Process ◽  
Human Body ◽  
The Body ◽  
Simulation Program ◽  
Crash Test ◽  
Low Speed ◽  
Simulated Model ◽  
Stiffness And Damping ◽  
Crash Tests

The article presents a model designed dummy for crash test in ADAMS. The simulated model dummy has dimensions, shapes and mass corresponding to a 50-percentile man. The simulation program allows modification of the dummy parameters. It allows to study the dynamics of motion, distribution of forces and loads of individual parts of the body of the simulated model. The article describes the design process and how to select the appropriate stiffness and damping joints for the simulated dummy. The article contains the results of simulation crash tests performed in the ADAMS program, which were compared to results of the Hybryd III dummy physical crash test. The simulation is designed to reflect the greatest compliance of the movements of individual parts of the human body during the low speed collision.

scholarly journals Energy Mechanisms of Free Vibrations and Resonance in Elastic Bodies

2021 ◽  
Author(s):  
Yuriy Alyushin
Keyword(s):  
Kinetic Energy ◽  
Elastic Deformation ◽  
Elastic Energy ◽  
Forced Vibrations ◽  
The Body ◽  
Kinematic Parameters ◽  
Conservation Of Energy ◽  
Average Value ◽  
The Law ◽  
External Forces

The mechanisms of natural oscillations and resonance are described, considering the peculiarities of the transformation of elastic and kinetic energy in the implementation of the law of conservation of energy in local and integral volumes of the body, using the concept of mechanics based on the concepts of space, time and energy. When describing the motion in the Lagrange form, the elastic deformation energy of the particles is determined by the quadratic invariant of the tensor, whose components are the partial derivatives of Euler variables with respect to Lagrange variables. The increment of the invariant due to elastic deformation is represented as the sum of two scalars, one of which depends on the average value of the relative lengths of the edges of the particles in the form of an infinitesimal parallelepiped, the second is equal to the standard deviation of these lengths from the average value. It is shown that each of the scalars can be represented in the form of two dimensionless kinematic parameters of elastic energy, which participate in different ways in the implementation of the law of conservation of energy. One part of the elastic energy passes into kinetic energy and participates in the implementation of the law of conservation of energy for the body as a whole, considering external forces. The second part is not converted into kinetic energy but changes the deformed state of the particles in accordance with the equations of motion while maintaining the same level of the part of the elastic energy of the particles used for this. The kinematic parameters differ from the volume density of the corresponding types of energy by a factor equal to the elastic modulus, which is directly proportional to the density and heat capacity of the material and inversely proportional to the volume compression coefficient. Transverse, torsional, and longitudinal vibrations are considered free and under resonance conditions. The mechanisms of transformation of forced vibrations into their own after the termination of external influences and resonance at the superposition of free and forced vibrations with the same or similar frequency are considered. The formation of a new free wave at each cycle with an increase in the amplitude, which occurs mainly due to internal energy sources, and not external forces, is justified.

Moving Cage: Vibration, Sonification and the Quanta of Time

2021 ◽  
Vol 46 (2) ◽  
pp. 169-183
Author(s):  
MARCUS CHENG CHYE TAN
Keyword(s):  
Kinetic Energy ◽  
The Body ◽  
Dance Movements ◽  
Politics Of The Body

Dear John is an experimental choreomusical work that reinterprets Cage's works while advancing his ideas of sound as sonic events and embodied choreography. In this episodic work, improvised movement unfolds to a soundscape of defamiliarized instruments, sound devices and sonicities of macro- and micro-movements. The correspondence and (in)congruence between dance movements and music's kinetic energy become the means to examine a politics of the body and sound, of music on movement. Additionally, in this ‘auditory architecture’ the quanta of time, its relations and (lack of) unity are exposed. This article then examines the intersubjective interplay of movement and music, body and sonicity; it considers the resonance of the performing body as intermaterial vibration and how this invites a sonic politics of relational possibility. The article will then also investigate the ways in which the interaction of motion and music, movement and stillness engenders experiences of time's indeterminacy and elasticity.

Optimal Self-Propulsion of a Deformable Prolate Spheroid

1983 ◽  
Vol 27 (02) ◽  
pp. 121-130
Author(s):  
T. Miloh
Keyword(s):  
Kinetic Energy ◽  
Surface Deformation ◽  
Deformable Body ◽  
Large Degree ◽  
Prolate Spheroid ◽  
The Body ◽  
Deformation Pattern ◽  
Inviscid Fluid ◽  
Periodic Surface ◽  
Deformation Velocity

The problem of self-propulsion of an elongated deformable body moving in an infinite medium of inviscid fluid is considered in some detail. A prolate spheroid is chosen as a model shape, and a particular deformation pattern which maximizes the Froude efficiency is sought. The Froude efficiency in this context is defined by the ratio of the kinetic energy of the body to the total kinetic energy of the system comprising the body and the fluid. It is demonstrated that a body can propel itself from rest in a persistent manner even for a periodic surface deformation with zero mean which preserves both the volume and the location of its centroid. Under these constraints the induced forward velocity of the body is of 0(ε2) where ε is the amplitude of the deformation velocity. It is also demonstrated that for a persistent self-propulsion to exist the body should develop a large degree of skewness, resulting from the interaction between the two deformation components—one with fore-and-aft symmetry and one without. It is also essential that the symmetric and asymmetric deformation components should be out of phase.

Secretions

2021 ◽  
pp. 119-158
Author(s):  
Rex Ferguson
Keyword(s):  
Twentieth Century ◽  
Science Fiction ◽  
Genetic Research ◽  
Forensic Analysis ◽  
Dna Profiling ◽  
The Body ◽  
Autobiographical Texts ◽  
Late Twentieth ◽  
Living Organisms ◽  
Late Twentieth Century

DNA profiling, in which individual being is identified by its cellular structures, was first developed by the geneticist Alec Jeffreys in the 1980s. That this source of identity also forms the instructions through which living organisms are generated has complicated profiling’s place in the cultural imaginary of the late twentieth century. So, while profiling actually deals only in non-coding regions of the genome—matter often referred to as ‘junk DNA’—the significance of DNA as a substance of forensic analysis, in the late twentieth century imaginary, is its resonance as the apparent blueprint of existence. The notable features that this blurring of concepts brings about include a conceptualization of identity as a mass of information; notions to do with codes and coding; the presence of the body in the fluids which spill beyond its bounds; and a sense of the body as an archive of heredity and primitivism. In writing specifically about genetic research, Richard Powers’s The Gold Bug Variations (1991) serves a dual function in this chapter, as both an explicatory document and thematic example. But the more substantive analysis is reserved for the work of J. G. Ballard which, from its science fiction origins in novels such as The Drowned World (1962), through the controversial era of Crash (1973), to its trilogy of autobiographical texts (Empire of the Sun (1984), The Kindness of Women (1991), and Miracles of Life (2008)) articulates a form of identity that has close, though often oblique, affinities with all the most prominent features of DNA profiling.

scholarly journals Ocean winter warming induced starvation of predator and prey

2020 ◽  
Vol 287 (1931) ◽  
pp. 20200970
Author(s):  
Frank Melzner ◽  
Björn Buchholz ◽  
Fabian Wolf ◽  
Ulrike Panknin ◽  
Marlene Wall
Keyword(s):  
Body Condition ◽  
Blue Mussel ◽  
Heat Waves ◽  
Marine Species ◽  
The Body ◽  
Reproductive Capacity ◽  
Sea Star ◽  
Conservation Of Energy ◽  
Winter Warming ◽  
Increasing Temperature

Ocean warming impacts the fitness of marine ectothermic species, leading to poleward range shifts, re-shuffling of communities, and changes in ecosystem services. While the detrimental effects of summer heat waves have been widely studied, little is known about the impacts of winter warming on marine species in temperate regions. Many species benefit from low winter temperature-induced reductions in metabolism, as these permit conservation of energy reserves that are needed to support reproduction in spring. Here, we used a unique outdoor mesocosm system to expose a coastal predator–prey system, the sea star Asterias and the blue mussel Mytilus , to different winter warming scenarios under near-natural conditions. We found that the body condition of mussels decreased in a linear fashion with increasing temperature. Sea star growth also decreased with increasing temperature, which was a function of unaltered predation rates and decreased mussel body condition. Asterias relative digestive gland mass strongly declined over the studied temperature interval ( ca twofold). This could have severe implications for reproductive capacity in the following spring, as digestive glands provide reserve compounds to maturing gonads. Thus, both predator and prey suffered from a mismatch of energy acquisition versus consumption in warmer winter scenarios, with pronounced consequences for food web energy transfer in future oceans.

Design of a Hybrid Lightweight Energy Absorber

2016 ◽  
Vol 713 ◽  
pp. 321-324
Author(s):  
A. de Luca ◽  
Giuseppe Lamanna ◽  
Raffaele Sepe ◽  
Alessandro Soprano
Keyword(s):  
Kinetic Energy ◽  
Numerical Investigation ◽  
Structural Design ◽  
Carbon Composite ◽  
Energy Absorber ◽  
Load Paths ◽  
Passenger Safety ◽  
Carbon Composite Materials ◽  
Energy Absorbers ◽  
Energy Absorbing

Among several problems which might affect the passenger safety during an accidental crash event, the deceleration pulse is one of the most critical. For this reason vehicles are designed to convert the Kinetic Energy occurring in an impact in plastic deformation and to spread the loads due to such events through designed structural load paths. An important role in the kinetic energy absorbing at high velocities is played by the energy absorbers. The energy absorption capability of a crashworthy element or system is largely affected by material properties and structural design. This work deals with a numerical investigation on the energy absorbing capability of a new concept of energy absorber made out of the combination of metal parts and carbon composite materials. A numerical investigation on the parameters which increase the crash performance as well as decrease the weight of such device has been presented in this paper.

The Application of Eddy-Viscosity Stress Limiters for Modeling Cross-Flow Separation

2010 ◽  
Vol 132 (9) ◽  
Author(s):  
P. A. Gregory ◽  
P. N. Joubert ◽  
M. S. Chong ◽  
A. Ooi
Keyword(s):  
Kinetic Energy ◽  
Skin Friction ◽  
Turbulent Kinetic Energy ◽  
Flow Separation ◽  
Eddy Viscosity ◽  
Cross Flow ◽  
The Body ◽  
Mean Flow ◽  
Viscosity Models ◽  
Experimental Apparatus

The ability of eddy-viscosity models to simulate the turbulent wake produced by cross-flow separation over a curved body of revolution is assessed. The results obtained using the standard k−ω model show excessive levels of turbulent kinetic energy k in the vicinity of the stagnation point at the nose of the body. Additionally, high levels of k are observed throughout the wake. Enforcing laminar flow upstream of the nose (which replicates the experimental apparatus more accurately) gives more accurate estimates of k throughout the flowfield. A stress limiter in the form of Durbin’s T-limit modification for eddy-viscosity models is implemented for the k−ω model, and its effect on the computed surface pressures, skin friction, and surface flow features is assessed. Additionally, the effect of the T-limit modification on both the mean flow and the turbulent flow quantities within the wake is also examined. The use of the T-limit modification gives significant improvements in predicted levels of turbulent kinetic energy and Reynolds stresses within the wake. However, predicted values of skin friction in regions of attached flow become up to 50% greater than the experimental values when the T-limit is used. This is due to higher values of near-wall turbulence being created with the T-limit.

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