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Introduction to shock & vibration

Introduction to shock & vibration gives an introduction to vibration through a description of the most common mechanical parameters leading to the behaviour of simple mass spring systems. Furthermore the different types of signals and their description is treated and the conversion between the different parameters is described mathematically and graphically. Finally the measurement units are defined.   | Introduction to Shock Vibration Definitions What is Vibration Mechanical Parameters Mass-spring Systems How to Quantify Vibration Signal Types Time Signal Descriptors Conversions Acceleration Velocity Displacement Units BA 7674-12 1 Briiel Kjaer r Abstract The lecture gives an introduction to vibration through a description of the most common mechanical parameters leading to the behaviour of simple mass-spring systems. Furthermore the different types of signals and their description is treated and the conversion between the different parameters is described mathematically and graphically. Finally the measurement units are defined. Copyright 1998 Bruel Kj r Sound and Vibration Measurement A S All Rights Reserved English BA 7674-12 Briiel Kjaer Definitions Vibration is an oscillation wherein the quantity is a parameter defining the motion of a mechanical system Oscillation is the variation usually with time of the magnitude of a quantity with respect to a specified reference when the magnitude is alternately greater and smaller than the reference BA 7674-12 2 Briiel Kjaer Definitions It is practical to know more precisely what we are going to talk about. These definitions are adapted from the Shock and Vibration Handbook by Harris and Crede see literature list . Page 2 Vibration In Everyday Life Briiel Kjaer BA 7674-12 3 What is Vibration Vibration is mechanical oscillation about a reference position. Vibration is an everyday phenomenon we meet it in our homes during transport and at work. Vibration is often a destructive and annoying side effect of a useful process but is sometimes generated intentionally to perform a task. Vibration of machines Vibration is a result of dynamic forces in machines which have moving parts and in structures which are connected to the machine. Different parts of the machine will vibrate with various frequencies and amplitudes. Vibration causes wear and fatigue. It is often responsible for the ultimate breakdown of the machine. Page