Introduction to Structural Impact

Christopher Wright, P.E.

Course Outline

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.

Learning Objective

At the conclusion of this four-hour course, the student will:

• Be familiar with common working assumptions for dealing with impact.
• Be introduced to some simple mathematical relationships suitable for design office use.
• Understand the basic features of elastic and inelastic impact.
• Understand applicability of impulse and momentum in assessing impact.
• Understand the use of the ductility factor as it applies to structural design.
• Understand the physical basis of impact and shock load in sufficient depth to make practical use of the mathematical fundamentals.
• Work through a variety of representative problems in shock and impact response.
• Be able to formulate approaches to commonly encountered structural impact problems.
• Be prepared to begin detailed study of more advanced structural dynamics.

Intended Audience

This course is intended for structural and mechanical engineers.

Course Introduction

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.

Course Content

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.

Course Summary

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.

Quiz

Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.

DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDHonline.com or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered professional engineer. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.