Introduction to Structural Impact
Christopher Wright, P.E.
This four hour
online course is an introduction to structural impact assessment for practicing
mechanical and structural engineers. The emphasis is on first principles and
methodology to address commonplace design problems. This course will enable
the designer to estimate impact loads and their effects routinely.
This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.
At the conclusion of this four-hour course, the student will:
This course is intended for structural and mechanical engineers.
At one time or
another most engineers run into cases of impact loading. The general problem
of impact is extremely complex, but reasonable and useful engineering estimates
are possible simply from considerations of a few first principles with some
simplifying assumptions. Irrespective of the complexity of the details, impact
necessarily involves conservation of energy and momentum. Impacting bodies conserve
momentum, and their kinetic energy will be partially converted to strain energy
in the target and partly dissipated through friction and local plastic deformation
and strain energy 'radiated' away as stress waves. The details are very difficult
to predict, but some simple estimates based on first principles can usually
result is reasonable estimates for response.
The course content is in a PDF file (82 K) Introduction to Structural Impact. You need to open or download above documents to study this course.
The physics of
impact necessarily involves conservation of energy and momentum. When a moving
object strikes a structure the force which decelerates the mass satisfies conservation
of momentum. The kinetic energy of the impacting body will be partially converted
to strain energy in the target and partly dissipated through friction and local
plastic deformation and strain energy 'radiated' away as stress waves.
The chief problem usually involves estimation of deformability. In real structures the deceleration is limited by elastic and plastic deformation, which in effect cushions the blow, and a major 'trick' is making a reasonable estimate the local compliance or stiffness at the point of impact.
Where impact is a routine service condition, the structure should remain elastic or nearly so. In other cases the requirement is to provide proof that the structure remain substantially intact, even though damaged. Local plastic deformation may be tolerated, provided the overall response is nearly elastic.
Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.