Basic Rules of Engineering Design
• Safe
• Simple
• Clear
Interrelationship Between the Safety Levels
Definition: Safety
Safety
• is a state in which the risk is smaller than the risk limit
Risk limit
• is the largest still acceptable system-specific risk relating to
a particular technical process or situation
Protection
• is the reduction of risk by suitable means to reduce the
frequency of the occurrence or the extent of damage or
both
Safety Aspects of a System
Aspects of Safety Technology
• Self-protection: product liability
• EC machinery directive : DIN EN 292;
VDE 100; VDI 2244
• CE-Certification: declaration of conformity
• ISO 9001: document management;
modification management; version
management
Aspects of Safety Technology
Market acceptance:
• safe and environment-friendly products
are received better by the market
• customers are prepared to pay more for
safer products
• safety leads to a positive brand image:
Mercedes, Volvo, Saab….
Safe Embodiment Design
Direct Safety Principles
Safe-Life
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Important Measures:
Over-dimensioning of parts
Clear and simple embodiment design
Field-tests for determining the actual loads
Employ experienced interdisciplinary teams for
the development
Documented quality assurance over the
complete life-cycle
Inspection/maintenance
Example: Fail-Safe
Redundancy Principle
Indirect Safety Principles
Control of a Safety Fence
Aspects of Warning Safety
Technology
• Lowest level of safety technology
supplementary to other measures
• minimum measure when no other safety
principle is applicable
• consider aspects of noticability and
ergonomics
Warnings
Aspects Concerning Safety Data
Sheets
• safety data sheets describe the danger potential
of materials and substances
• the danger potential of materials and substances
must be considered over the complete life cycle
of a product:
• - production
• - commissioning
• - operation
• safety data sheets are a part of the product
documentation
Material Aspect of Safety
Technology
• The safety of a product can be increased
by choosing a material that suits the
operating conditions of the product
• Determining the operating conditions is
crucial for the choice of materials:
• - corrosion resistant materials
• - fatigue resistant materials
• - materials that have a good adhesion to
lubricants
Selecting Material Designed for
Safety
The Nature of Principles of
Embodiment Design
Aim of Principles of Embodiment
Design
• The application of principles of embodiment design leads to products that are
optimally designed – regarding the
requirements taken into account!
Direct and Short Force
Transmission Path
Direct and Short Force
Transmission
Direct and short force
transmission
Direct and Short Force
Transmission
• Flowlines of force must always be closed
• Force transmission must be as short as
possible
Avoid:
• deflection of forces
• discontinuous change of cross-section
• change of density of force flowlines
Direct and short force
transmission
Idea of force transmission
Definition:The basic idea and illustration of force and moment transmission
is taken from the field of fluid mechanicsSource:
Direct and short force
transmission
Fundamentals:
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The flowlines of force should
always be closed. (Inertial forces
are not taken in to consideration)
The stresses and strains change
with in circular flowlinesof force.
The flowlinesof force searches the
shortest path
The flowlinesof force come closer
in narrow cross sectional areas.On the other hand, they expand in
broad cross sectional areas
Direct, Short Force
Transmission: Welding
Direct Force Transmission:
Bearing Pedestal
Direct Force Transmission:
Relief Notches
Matched Deformation:
Shaft-Hub Connection
• Principle of Balanced Forces
• Target:
• Reached by: system is free of forces to
the outside
• symmetric structure of the system
regarding the flow of forces