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- 1Reduction of costs using virtual prototypingthe variable cost in development are high and therefore this process has best opportunities for reducing cost (by virtual prototyping)
we need a lot of info in the early stage to choose right boundaries conditions.
simulation gives answer to questions. simulation optimizes the construction, helps to choos best shape and material and helps to consider all boundaries for product. - 2Frontloadingaim: to realize function, performance, technological and other characteristics of a product as early as possible in the development with the help of virtual prototyping (without doing expermiments and test real prototypes).
early competition and time reduction means that we need more ressources - 3philosophy of virtual prototypingdesign verification is possible in an early stage. there are more opportunities to refining, iterating and optimaziation.
cut time and costs-> imporve quaility-> increase efficiency - 4front up informationmore information in shorter time in the product development process -> reduction of risks
- 5why is sumlation advantageous?- testing can be impossible
- it can be that testing is not a desirable option
- very often testing is much more expensive - 6general procedure of numerical simulationphenomenon, process
-> mathematical model
mathematical model
-> numeric
numerical algorithmn
-> implementation
simulation - code
-> visualization
results (for interpretation) - 7what are mathematical and numerical models?mathematical model= simplified abstraction of reality
numerical model= used when there is no closed form solution available for the mathematical model - 8model complexitywith 20% effort/cost => 80% of information value can be achieved
- 9what can simulation be used for?validation
calibration
numerical experiments
sensitivity analysis - 10what is a dynamical system?a mathematical model describing the time-evolution of physical, chemical, biological and technical processes.
real process and its dynamical systems are not identically. there is no unique dynamical system which describs the prcoess in real life. development of dynamical system called "modelling" - 11what is a DMU?- digital mock up = virtual prototype.
- is a real description of a product within a PC enviroment.
- database
- used to test and verify product functionalities
- if used in very eary stage: -> aim: digital definition of the whole product and its functional analysis of basic features - 12demans on DMU (7)- high quality visualization and 3D prototyping
- packaging
- kinematic simulation
- comparisons of variants
- envelope volumina
- feedback into the construction process
- assembly / disassembly investigations - 13DMU functions (7)- overall modell
- visualization
- assembly / disassembly analysis
- analysis of tolerances
- investigations of surfaces
- investigation of ergonomy
- cuts and digital memos - 14what is VR and AR?Virtual reality= computer generated virtual environment serving as a user interface
augmented reality= a real scene, that keeps to be visible by using a semi-transparent display of a data helmet, is augmented with computer generated information - 15usage of VR and AR in the product life cycle?VR: product planning, design, testing, research and manufacturing
AR: product use, distribution, manufacture, testing, liquidation - 16applications of VR (6)- product presentation for marketing
- product styling and design
- DMU
- packaging
- production
- visualization of architectural surroundings - 17applications of AR? (7)- augmented design review
- augmented mock-ups
- process support in the production
- maintenance and service
- support and training
- assembly / disassembly
- verification of sumulation results - 18what is a finite element node DOF?finite element= geometric unit topology that is used for interpolation of the displacement field (using these is an approximation)
node= corner or middle node of an element, being used to connect adjacent elements.
DOF= degree of freedom, component of displacement at a node (max. 3 rotation, 3 translation=6 DOF/node) - 19what does discretisation mean?devide into small pieces= meshing
complex problem, looking for displacements of single nodes in a mesh, doing an interpolation in between - 20types of analysisstatic:
- linear (eigenfrequenzy analysis)
- non linear (response analysis) - 21what are restraints and constraints?restraints= selected DOF at selected nodes are blocked.
constraints= are used for coupling of DOF at selected nodes. - 22what is the job of the solver?- solves a linar, algebraic system of equations
important:
- computation rises quadratically by the number of nodes
- memory demans
- results are displacements - 23visualization of stresses- calcuated from displacements/deformations
- stresses are always less accurate than displacements
- important stress results :
-> von-mises-stress
-> maximum principal stress
-> minimum principal stress - 24what is a multi body system? (4)- assemble of n solid bodies
- bodies are somehow connected
- forces may act on bodies
- entire mechanism is "doing something" - 25components of a multi body system ?5 elements
- interial system
- ridig body
-flexible body
- constraints
- forces - 26modes of analysis
- 27FEA and MBSFEA= finite element analysis
+ linear, elastic structures with many DOF
- simulations with nonlinearities are not efficient
MBS= multi body system
+ efficient with nonlinear simulations
- limited to rigid bodies
combined boths are the best solution -> strength of each method - 28applications of MBS (6)- drive trains
- wind energy plants
- material transport
- mechatronic or hydraulic systems
- physiotherapy
- rehabilitation - 29what is CFD?- computational fluid dynamics deals with computation of the behaviour of non solid medias based on mathematical equations
- results of CFD computations relevant data like pressure, velocity, temperature, density
- used for: optimazation of design, conceptual studies of new design, detailed product development, investigation of existing problems
- CFD delivers a qualitative understanding of the flow distribution - 30advantages of CFD? (5)- cost and time reduction for smaller models
- parameter studies withing a large range
- detection of loss mechanism
- simulation the "perfect" condition
- comprehensive information - 31disadvantage of CFD? (3)- computational time and cost can be very high for large models
- CFD-model versus reality
- models need to be validated - 32applications of CFD (4)- automotive industry
- space and air industry
- energy industry
- chemical industry - 33when to use CFD? (6)- if structures can not be scaled for test
- when detailed component information is required
- when complex and chemical processes needs to be investigated
- when empiric data are not available
- investigations of critical conditions with high risk
- configuration with can not be tested - 34workflow of fatigue analysis?load spectrum (rainflow, stepped, sythetic) , specimen data, FE-Data(node or element stresses, influence factors) are computed to get results in damage and safety factors
- 35what is equivalent stress?- comparison of strain energy
- idea: that it causes the same damage in the material as the real multi-axial stress tensor does
- all equivalent stress are based on hypotheses
- no best choice - 36classification of loads- static load
- alternating load
- pulsating load
- general load - 37what is a loval SN curve?- SN curve is different for any postition
- influence factors:
*material
* stress gradient
*mean stress
*surface properties
*local temperature - 38what is the difference between the conventional development process and optimazation?conventional= design and boundary conditions determine in design analysis to get perfomance
optimazation= perfomance and boundarys conditions determine in design optimazation to get design - 39what is the difference between stress based and damage based optimazation?stress based= just one instance in time
damage based= integration of stress effects in a given time frame - 40what is a design space and frozen areas?design space= area which is possible for topology optimazation
frozen areas= cannot be changed - 41describe the work flow of experimental fatigue testing (6)data flow:
- application
- data recording
- field test
- data processing
- FEM analysis
- test bench - 42what are benefits of virtual test bench? (4)- shorten product development cycles
- support for real test bench, if there occurs problems
- effects at real set-ups at modified paramenter
- co-operation of MBS simulation and FEM analysis
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- DPE Karteikarten am DPE, erstellt von anna nina am 30/11/2014.
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- anna nina
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