Yacht Design School – Lesson 12/13

Basic Principles of Material and Structural Analysis, Testing & Scantlings Rule Development

Revised 08/09/2020 – Copyright 2020


Books Recommended for Relevance to These Lessons

 Analysis and Design of Aircraft Structures, 1949 Revised Edition by E.F. Bruhn (an aircraft based book but teaches basic stress analysis extremely well.*
                ANC-18 Design of Wood Aircraft Structures (not much directly applicable to yachts, but can be mined for some good structural information
                An In-House Low-Cost Program for Testing Laminates by Robert A. Schofield (a primary source for our sections on testing, Professional Boatbuilder August/September 1997
Composite Materials Handbook
Volume 1:  Polymer Matrix Composites, Guidelines for Characterization of Structural Material, MIL-HDBK-17-1F
                    Volume 2:  Polymer Matrix Composites Materials Properties, MIL-HDBK-17-2F
                    Volume3:  Polymer Matrix Composites Materials Usage, Design, and Analysis, MIL-HDBK-17-3F
                    Volume4:  Metal Matrix Composites, MIL-HDBK-17-4A

    Volume5:  Ceramic Matrix Composites, MIL-HDBK-5

Desktop Engineering (monthly free subscription www.deskeng.com )

Engineering Mathematics by K.A. Stroud & Dexter J. Booth

High Performance Composites (bi-monthly free subscription www.compositesworld.com )

Laminar Aircraft Sturcutres by Alex Strojnik (not necessary to read but was consulted for our section on materials testing
Machinery’s Handbook
published by Industrial Press

Marks’ Standard Handbook for Mechanical Engineers by Avallone & Baumeister

Marks’ Mechanics by Larry Silverberg & James P. Thrower
                Materials Properties Handbook - For Marine and Aerospace Construction by Thomas A. MacNaughton* (An exploration of moduli)

Mechanics of Composite Structures by Laslo P. Kollar & George S. Springer
                Practical Stress Analysis for Design Engineers
by Jean-Claude Flabel (an aircraft based text by a lot of useful thinking in it)
                Roark’s Formulas for Stress and Strain
by Warren C. Young & Richard G. Budynas*

Wood Handbook – Wood as an Engineering Material, Forest Products Laboratory

(This book may be downloaded in .pdf format at http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/fplgtr113.htm

www.efunda.com for materials and engineering research

www.matweb.com for materials properties research


Tools for This Lesson

Calibrated Weights (These are described and sourced under the testing section below and are used with the Cantilevered Beam Test Fixture)

Cantilevered Beam Test Fixture (This is the simplest materials testing fixuture.  See the plans under "What You Will Receive with This Lesson.)

Universal Test Machine (Plans for this machine and add-on fixtures are given under "What You Will Receive with This Lesson" below.  The operating instructions are given later in these lessons.
            Strojnk Test Jig (Rough jig likely buildable from parts wyou can scrounge from family and friends, but not a very good solution.  See plans, operation instructions, and math later in these lessons.

The Laminator by www.thelaminator.net (a $29 program to analyze composite laminates.  This program is required.


What You Will Receive With This Lesson
            YDS Test Fixture Cantilevered Beam.pdf
            YDS Test Machine Universal.pdf
            YDS Test Machine Core Shear AddOn.pdf
            YDS Test Machine Shear AddOn.pdf
            YDS Test Machine ShearDoubleShear AddOn.pdf
            YDS Test Machine Tensile AddOn.pdf

What You Will Learn In These Lessons


Basic Materials Science

            The Internal Structure of Materials

            Stress Versus Strain
                            Tensile Strength

            Compression Strength

            Shear Strength

            Proportional Limit

            Elastic Limit

            Yield Strength

            Ultimate Strength

            Poisson’s Ratio



            Isotropic Versus Non-Isotropic Materials

Basic Structural Analysis

            Young’s Modulus of Elasticity and related Moduli

            Relating Material Constants


Moment of Inertia & Buckling

Polar Moment of Inertia, Torsion, Torque, and Shaft Design

Section Modulus & Bending

Beam Theory

Stress and Deflection in Marine Structures

Panel Theory

                        Avoidance of Stress Concentration

                        Differences Between Isotropic and Non-Isotropic Materials

                        Fastenings & Joints

            Materials Properties

Fatigue Characteristics & Fatigue Limits

Safety Factors as Determined by Fatigue Limits & Analysis Limitations

Evaluating the Number of Significant Digits
                Explanation of Statics

Statics Versus Dynamics

Impact Studies


            Vector Analysis - Graphic

            Vector Analysis - Calculated

            Marine Environmental Factors

            Composite Structures
                        Additional Concepts Needed

                        Micromechanics of Composite Structures

                        Rule of Mixtures & Modified Rule of Mixtures

                        Composite Laminates Evaluation Programs

                        Introduction to Using “The Laminator”

                        Theory of Composite Beams

                        Theory of Composite Panels


                        Test Equipment
                        Importance of Standardized Tests
                        Sources of Materials & Equipment  
                        To Measure Stress Versus Strain in Various Ways
                        Determining the Flexural Modulus Using a Cantilevered Beam
                        Flexural Modulus Using the Universal Test Machine & Force Gauge
                        Tensile Testing Using UTM

                        Shear Testing of Materials Using UTM

                        Core Shear Using UTM
                       Cored Beams in Bending
                       Pins in Shear and Double Shear Using UTM
                       For Compression Strength

                        Determining Poisson’s Ratio

                        Determining Modulus of Elasticity in Bending

                        Special Considerations for Composites

                        Not Using Fully Distributed Load Testing & Why      


            Real World Testing
                    Standard Deviation for Evaluating Number of Samples and Test Results
           Scale Model Testing

            Proper and Improper Use of Structural Analysis & Testing in Vessel Design

            Development of Judgment
            A Broader Understanding of Structural Questions




                        Ease of Repair

                        Ease of Production

                        Fatigue Avoidance

            Design Methodology

                        Design Through Testing

                        Design Through Mathematical Models

                        Combining Analysis & Testing

Developing Minimum Standards for Hull Structures

            Minimum Strengths

            Minimum Stiffness

            Safety Factors by Material as Determined by Their Fatigue Limits

            Impact Criteria

            Why Linear Measurements Are Not the Way to Go

            Cube Root of the Displacement in Cubic Feet

            Cautions on the Limitations of Various Certification Societies

            Static Versus Dynamic Assumptions & Other Questions

Special Topics

            Multihull Beam Design          
                            Special Calculations in Exotic Keel Types
                            Submarine Design Basics as an Exercise

                            Foundry Work
                            Simple Machines
                            Ports & Windows

Types of Structures and Mathematical Solutions

            An Introduction to Roark’s Formulas for Stress and Strain

            Limitations of the Structural Analyses in This Lesson

            More Exotic Analysis Methods
                        Use of Differentiation & Integration in Achieving More Accurate Results

                        Finite Element Analysis Introduced
                       Computational Fluid Dynamics Introduced
                       Introduction to On Screen Math Packages

            Information Sources
           Appendix A: Standard Deviation Spreadsheet


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