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Preface | |

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List of Symbols | |

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Introduction | |

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Vibration Sources | |

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Definitions | |

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Vibration Representation | |

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Degrees of Freedom | |

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Vibration Modes | |

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Vibration Nodes | |

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Coupled Modes | |

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Fasteners | |

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Electronic Equipment for Airplanes and Missiles | |

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Electronic Equipment for Ships and Submarines | |

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Electronic Equipment for Automobiles, Trucks, and Trains | |

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Electronics for Oil Drilling Equipment | |

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Electronics for Computers, Communication, and Entertainment | |

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Vibrations of Simple Electronic Systems | |

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Single Spring-Mass System Without Damping | |

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Sample Problem--Natural Frequency of a Cantilever Beam | |

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Single-Degree-of-Freedom Torsional Systems | |

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Sample Problem--Natural Frequency of a Torsion System | |

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Springs in Series and Parallel | |

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Sample Problem--Resonant Frequency of a Spring System | |

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Relation of Frequency and Acceleration to Displacement | |

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Sample Problem--Natural Frequency and Stress in a Beam | |

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Forced Vibrations with Viscous Damping | |

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Transmissibility as a Function of Frequency | |

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Sample Problem--Relating the Resonant Frequency to the Dynamic Displacement | |

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Multiple Spring--Mass Systems Without Damping | |

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Sample Problem--Resonant Frequency of a System | |

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Component Lead Wire and Solder Joint Vibration Fatigue Life | |

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Introduction | |

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Vibration Problems with Components Mounted High Above the PCB | |

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Sample Problem--Vibration Fatigue Life in the Wires of a TO-5 Transistor | |

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Vibration Fatigue Life in Solder Joints of a TO-5 Transistor | |

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Recommendations to Fix the Wire Vibration Problem | |

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Dynamic Forces Developed in Transformer Wires During Vibration | |

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Sample Problem--Dynamic Forces and Fatigue Life in Transformer Lead Wires | |

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Relative Displacements Between PCB and Component Produce Lead Wire Strain | |

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Sample Problem--Effects of PCB Displacement on Hybrid Reliability | |

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Beam Structures for Electronic Subassemblies | |

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Natural Frequency of a Uniform Beam | |

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Sample Problem--Natural Frequencies of Beams | |

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Nonuniform Cross Sections | |

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Sample Problem--Natural Frequency of a Box with Nonuniform Sections | |

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Composite Beams | |

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Component Lead Wires as Bents, Frames, and Arcs | |

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Electronic Components Mounted on Circuit Boards | |

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Bent with a Lateral Load--Hinged Ends | |

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Strain Energy--Bent with Hinged Ends | |

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Strain Energy--Bent with Fixed Ends | |

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Strain Energy--Circular Arc with Hinged Ends | |

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Strain Energy--Circular Arc with Fixed Ends | |

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Strain Energy--Circular Arcs for Lead Wire Strain Relief | |

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Sample Problem--Adding an Offset in a Wire to Increase the Fatigue Life | |

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Printed Circuit Boards and Flat Plates | |

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Various Types of Printed Circuit Boards | |

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Changes in Circuit Board Edge Conditions | |

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Estimating the Transmissibility of a Printed Circuit Board | |

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Natural Frequency Using a Trigonometric Series | |

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Natural Frequency Using a Polynomial Series | |

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Sample Problem--Resonant Frequency of a PCB | |

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Natural Frequency Equations Derived Using the Rayleigh Method | |

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Dynamic Stresses in the Circuit Board | |

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Sample Problem--Vibration Stresses in a PCB | |

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Ribs on Printed Circuit Boards | |

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Ribs Fastened to Circuit Boards with Screws | |

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Printed Circuit Boards With Ribs in Two Directions | |

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Proper Use of Ribs to Stiffen Plates and Circuit Boards | |

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Quick Way to Estimate the Required Rib Spacing for Circuit Boards | |

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Natural Frequencies for Different PCB Shapes with Different Supports | |

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Sample Problem--Natural Frequency of a Triangular PCB with Three Point Supports | |

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Octave Rule, Snubbing, and Damping to Increase the PCB Fatigue Life | |

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Dynamic Coupling Between the PCBs and Their Support Structures | |

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Effects of Loose Edge Guides on Plug-in Type PCBs | |

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Description of Dynamic Computer Study for the Octave Rule | |

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The Forward Octave Rule Always Works | |

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The Reverse Octave Rule Must Have Lightweight PCBs | |

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Sample Problem--Vibration Problems with Relays Mounted on PCBs | |

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Proposed Corrective Action for Relays | |

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Using Snubbers to Reduce PCB Displacements and Stresses | |

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Sample Problem--Adding Snubbers to Improve PCB Reliability | |

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Controlling the PCB Transmissibility with Damping | |

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Properties of Material Damping | |

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Constrained Layer Damping with Viscoelastic Materials | |

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Why Stiffening Ribs on PCBs are Often Better than Damping | |

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Problems with PCB Viscoelastic Dampers | |

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Preventing Sinusoidal Vibration Failures in Electronic Equipment | |

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Introduction | |

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Estimating the Vibration Fatigue Life | |

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Sample Problem--Qualification Test for an Electronic System | |

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Electronic Component Lead Wire Strain Relief | |

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Designing PCBs for Sinusoidal Vibration Environments | |

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Sample Problem--Determining Desired PCB Resonant Frequency | |

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How Location and Orientation of Component on PCB Affect Life | |

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How Wedge Clamps Affect the PCB Resonant Frequency | |

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Sample Problem--Resonant Frequency of PCB with Side Wedge Clamps | |

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Effects of Loose PCB Side Edge Guides | |

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Sample Problem--Resonant Frequency of PCB with Loose Edge Guides | |

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Sine Sweep Through a Resonance | |

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Sample Problem--Fatigue Cycles Accumulated During a Sine Sweep | |

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Designing Electronics for Random Vibration | |

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Introduction | |

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Basic Failure Modes in Random Vibration | |

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Characteristics of Random Vibration | |

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Differences Between Sinusoidal and Random Vibrations | |

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Random Vibration Input Curves | |

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Sample Problem--Determining the Input RMS Acceleration Level | |

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Random Vibration Units | |

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Shaped Random Vibration Input Curves | |

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Sample Problem--Input RMS Accelerations for Sloped PSD Curves | |

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Relation Between Decibels and Slope | |

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Integration Method for Obtaining the Area Under a PSD Curve | |

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Finding Points on the PSD Curve | |

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Sample Problem--Finding PSD Values | |

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Using Basic Logarithms to Find Points on the PSD Curve | |

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Probability Distribution Functions | |

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Gaussian or Normal Distribution Curve | |

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Correlating Random Vibration Failures Using the Three-Band Technique | |

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Rayleigh Distribution Function | |

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Response of a Single-Degree-of-Freedom System to Random Vibration | |

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Sample Problem--Estimating the Random Vibration Fatigue Life | |

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How PCBs Respond to Random Vibration | |

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Designing PCBs for Random Vibration Environments | |

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Sample Problem--Finding the Desired PCB Resonant Frequency | |

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Effects of Relative Motion on Component Fatigue Life | |

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Sample Problem--Component Fatigue Life | |

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It's the Input PSD that Counts, Not the Input RMS Acceleration | |

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Connector Wear and Surface Fretting Corrosion | |

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Sample Problem--Determining Approximate Connector Fatigue Life | |

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Multiple-Degree-of-Freedom Systems | |

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Octave Rule for Random Vibration | |

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Sample Problem--Response of Chassis and PCB to Random Vibration | |

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Sample Problem--Dynamic Analysis of an Electronic Chassis | |

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Determining the Number of Positive Zero Crossings | |

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Sample Problem--Determining the Number of Positive Zero Crossings | |

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Acoustic Noise Effects on Electronics | |

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Introduction | |

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Sample Problem--Determining the Sound Pressure Level | |

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Microphonic Effects in Electronic Equipment | |

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Methods for Generating Acoustic Noise Tests | |

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One-Third Octave Bandwidth | |

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Determining the Sound Pressure Spectral Density | |

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Sound Pressure Response to Acoustic Noise Excitation | |

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Sample Problem--Fatigue Life of a Sheet-Metal Panel Exposed to Acoustic Noise | |

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Determining the Sound Acceleration Spectral Density | |

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Sample Problem--Alternate Method of Acoustic Noise Analysis | |

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Designing Electronics for Shock Environments | |

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Introduction | |

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Specifying the Shock Environment | |

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Pulse Shock | |

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Half-Sine Shock Pulse for Zero Rebound and Full Rebound | |

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Sample Problem--Half-Sine Shock-Pulse Drop Test | |

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Response of Electronic Structures to Shock Pulses | |

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Response of a Simple System to Various Shock Pulses | |

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How PCBs Respond to Shock Pulses | |

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Determining the Desired PCB Resonant Frequency for Shock | |

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Sample Problem--Response of a PCB to a Half-Sine Shock Pulse | |

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Response of PCB to Other Shock Pulses | |

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Sample Problem--Shock Response of a Transformer Mounting Bracket | |

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Equivalent Shock Pulse | |

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Sample Problem--Shipping Crate for an Electronic Box | |

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Low Values of the Frequency Ratio R | |

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Sample Problem--Shock Amplification for Low Frequency Ratio R | |

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Shock Isolators | |

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Sample Problem--Heat Developed in an Isolator | |

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Information Required for Shock Isolators | |

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Sample Problem--Selecting a Set of Shock Isolators | |

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Ringing Effects in Systems with Light Damping | |

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How Two-Degree-of-Freedom Systems Respond to Shock | |

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The Octave Rule for Shock | |

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Velocity Shock | |

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Sample Problem--Designing a Cabinet for Velocity Shock | |

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Nonlinear Velocity Shock | |

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Sample Problem--Cushioning Material for a Sensitive Electronic Box | |

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Shock Response Spectrum | |

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How Chassis and PCBs Respond to Shock | |

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Sample Problem--Shock Response Spectrum Analysis for Chassis and PCB | |

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How Pyrotechnic Shock Can Affect Electronic Components | |

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Sample Problem--Resonant Frequency of a Hybrid Die Bond Wire | |

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Design and Analysis of Electronic Boxes | |

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Introduction | |

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Different Types of Mounts | |

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Preliminary Dynamic Analysis | |

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Bolted Covers | |

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Coupled Modes | |

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Dynamic Loads in a Chassis | |

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Bending Stresses in the Chassis | |

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Buckling Stress Ratio for Bending | |

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Torsional Stresses in the Chassis | |

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Buckling Stress Ratio for Shear | |

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Margin of Safety for Buckling | |

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Center-of-Gravity Mount | |

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Simpler Method for Obtaining Dynamic Forces and Stresses on a Chassis | |

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Effects of Manufacturing Methods on the Reliability of Electronics | |

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Introduction | |

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Typical Tolerances in Electronic Components and Lead Wires | |

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Sample Problem--Effects of PCB Tolerances on Frequency and Fatigue Life | |

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Problems Associated with Tolerances on PCB Thickness | |

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Effects of Poor Bonding Methods on Structural Stiffness | |

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Soldering Small Axial Leaded Components on Through-Hole PCBs | |

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Areas Where Poor Manufacturing Methods Have Been Known to Cause Problems | |

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Avionic Integrity Program and Automotive Integrity Program (AVIP) | |

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The Basic Philosophy for Performing an AVIP Analysis | |

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Different Perspectives of Reliability | |

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Vibration Fixtures and Vibration Testing | |

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Vibration Simulation Equipment | |

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Mounting the Vibration Machine | |

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Vibration Test Fixtures | |

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Basic Fixture Design Considerations | |

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Effective Spring Rates for Bolts | |

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Bolt Preload Torque | |

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Sample Problem--Determining Desired Bolt Torque | |

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Rocking Modes and Overturning Moments | |

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Oil-Film Slider Tables | |

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Vibration Fixture Counterweights | |

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A Summary for Good Fixture Design | |

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Suspension Systems | |

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Mechanical Fuses | |

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Distinguishing Bending Modes from Rocking Modes | |

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Push-Bar Couplings | |

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Slider Plate Longitudinal Resonance | |

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Acceleration Force Capability of Shaker | |

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Positioning the Servo-Control Accelerometer | |

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More Accurate Method for Estimating the Transmissibility Q in Structures | |

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Sample Problem--Transmissibility Expected for a Plug-in PCB | |

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Bibration Testing Case Histories | |

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Cross-Coupling Effects in Vibration Test Fixtures | |

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Progressive Vibration Shear Failures in Bolted Structures | |

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Vibration Push-Bar Couplers with Bolts Loaded in Shear | |

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Bolting PCB Centers Together to Improve Their Vibration Fatigue Life | |

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Vibration Failures Caused by Careless Manufacturing Methods | |

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Alleged Vibration Failure that was Really Caused by Dropping a Large Chassis | |

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Methods for Increasing the Vibration and Shock Capability on Existing Systems | |

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Environmental Stress Screening for Electronic Equipment (ESSEE) | |

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Introduction | |

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Environmental Stress Screening Philosophy | |

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Screening Environments | |

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Things an Acceptable Screen Are Expected to Do | |

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Things an Acceptable Screen Are Not Expected to Do | |

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To Screen or Not to Screen, That is the Problem | |

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Preparations Prior to the Start of a Screening Program | |

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Combined Thermal Cycling, Random Vibration, and Electrical Operation | |

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Separate Thermal Cycling, Random Vibration, and Electrical Operation | |

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Importance of the Screening Environment Sequence | |

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How Damage Can Be Developed in a Thermal Cycling Screen | |

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Estimating the Amount of Fatigue Life Used Up in a Random Vibration Screen | |

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Sample Problem--Fatigue Life Used Up in Vibration and Thermal Cycling Screen | |

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Bibliography | |

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Index | |