It is written for the benefit of someone who has (or can gain access to) basic hand and power tools. The sections of the document are arranged in logical order presuming a minimal knowledge of the metalworking trades in general or of springmaking in particular, and cross-linked to provide a forward path that leads from this point through the entire manufacturing process. There’s a glossary of spring terminology and an addendum, which should help you to define terms and find additional resources. Three basic types of springs are described: compression, extension, and torsion, alongside clock and power and other types of springs.

The experience in the design and analysis of aircraft wheels and brakes, brake systems, brake control systems, and antiskid systems is summarised.

The static and fatigue strength of aircraft wheels, calculation of brake service life, brake dynamics, techniques for increasing brake energy absorption capacity, and design of the basic antiskid system elements are also examined.

The book can be read online or downloaded in pdf, EPUB, Kindle, and plain text formats.

The consequences of something breaking can be a pest, or utterly disastrous, as when the pedal drops off one’s bike, but without it, biting and crunching, breaking into crisp packets, pulverizing coal, oil drilling and many other processes would be impossible. The most dramatic failures are catastrophic, but sometimes they can be very gradual even in the most brittle materials. This TLP discusses what determines when a material will break, and whether failure will be catastrophic or more gradual. The emphasis here is on brittle fracture, and although all of this is relevant to metals, the details of ductile fracture are not discussed.

On completion of this tutorial you should understand:
• that materials break by cracking;
• what determines whether a material will crack or not;
• what determines whether cracking is catastrophic or more gradual;
• the concepts of the fracture energy, strain energy release rate, fracture toughness and stress intensity factor.

Questions and links to further reading are also included.

[Description and screenshot taken from the DoITPoMS page for this TLP. (c) University of Cambridge used under the terms of their CC BY-NC-SA 2.0 license.]

There are no specific prerequisites for this TLP, but it would be useful to be familiar with stress and strain, elastic strain and Plastic deformation, Young modulus, E and yield stress, σY. While a basic knowledge of mechanical deformation is assumed, this teaching and learning package covers all the fundamentals of beam mechanics.

On completion of this tutorial package, you should:

• Understand the stress distribution within beams subject to bending or torsion.
• Be familiar with the concepts of the radius of curvature of a section of a beam (and its reciprocal, the curvature), second moment of area, polar moment of inertia, beam stiffness and torsional stiffness.
• Be able to calculate the moments acting in a beam subject to bending or torsion.
• Be able to calculate the deflections of a beam on bending and the angle of twist of a bar under torsion.
• Be able to predict the effect of plastic deformation, at least with simple beam geometry.

Questions and links to further reading and websites are also included.

[Description and screenshot taken from the DoITPoMS page for this TLP. (c) University of Cambridge used under the terms of their CC BY-NC-SA 2.0 license.]

Structural integrity is the study of the safe design and assessment of components and structures under load, and has become increasingly important in engineering design. It integrates aspects of stress analysis, materials behaviour and the mechanics of failure into the engineering design process.
After you have completed this unit you should be able to:
• differentiate between and describe dissolution, degredation and corrosion as they affect the deterioration of structural materials;
• predict electrochemical behaviour between dissimilar metals;
• explain galvanic corrosion in terms of the electrochemical series;
• distinguish between the hoop and longitudinal stresses in a pressure-vessel wall, and specify them in terms of the pressure, wall thickness and diameter of the vessel;
• describe the loads in the various parts of a structure and the most likely load path;
• indicate the procedures needed in practical failure analysis;
• specify the failure mechanisms possible when a nominally ductile material fails in a brittle fashion;
• relate crack formation to the loads on a component, bearing in mind the importance of stress concentrations in the component concerned;
• provide a likely sequence of events involved in the failure of a part made from several different components;
• describe the problem of fretting wear at a bearing joint;
• describe the key circumstances of a particular accident or disaster, and relate the sequence of events to specific causes supported by the relevant evidence.

The unit is split into 3 parts:
[1] Engineering for purpose
[2] Environmental deterioration
[3] Case study: The Silver Bridge

The unit takes on average 20 hours to complete.

[Description and screenshot taken from the OU page for this course. (c) Open University used under the terms of their CC BY-NC-SA 2.0 license.]

Kinematics is the study of motion. Statics is the study of forces on stationary objects. Dynamics is the study of forces on moving bodies. These are the analytical tools used by the design engineer. The aims of the course are therefore two fold. Firstly, it aims to teach the basic analytical methods, that is, the fundamental concepts and techniques of solid engineering mechanics. Secondly, it aims, in a limited way, to show the implementation of these methods in engineering design. The limited time available to study the course has meant that the course team have had to lay the emphasis on the analytical methods. The underlying assumption has been that, if students acquired a solid foundation in analysis from this course, then its implementation in design would become apparent both in future courses and in the mechanical engineering that surrounds them every day.

Course materials:
Block 1: Geometry of mechanisms
Unit 1: Mechanisms
Unit 2: Mechanisms 2
Block 2: Statics
Unit 3: Forced and moments
Unit 4: Modelling with free-body diagrams
Block 3: Kinematics
Unit 5: Motion
Unit 6: Velocity diagrams
Block 4: Dynamics
Unit 7/8: Dynamics
Block 5: Acceleration
Unit 9A: Compensation forces
Unit 9B: Acceleration diagrams
Block 6: Structures
Unit 10: Stress analysis
Unit 11: Structural components
Block 7: Energy and momentum
Unit 12/13: Energy and momentum
Block 8: Vibration
Unit 14: Vibration
Block 9: Design study
Unit 15: The mechanics of an electric lift

The unit takes on average 135 hours to complete.

[Description and screenshot taken from OpenLearn page for this material. (c) Open University used under the terms of their CC BY-NC-SA 2.0 license.]

You can use this guide together with manufacturers catalogues to specify and select a clutch that will meet your needs. If you are not very familiar with the standard types of clutch available from stock then review the sections on Uses of clutches and Types of clutch available from manufacturers. Reference should be made at every stage of the selection process to the Product Design Specification (PDS) for the system (all the relevant factors should be described in a well written PDS). The characteristics of clutches available “off the shelf” often may constrain the design of the system that requires the clutch so be prepared to change your design to match a manufacturer’s clutch. The guide also specifies the environment and the requirements for the clutch, how to choose a clutch, and a list of clutch suppliers.

[Description and screenshot taken from the SEED Curriculum for Engineering Design page for this guide. (c) The Design Society used under the terms of their (CC BY-NC-SA 3.0) license.]

The purpose of this guide is to enable the user to determine the attributes required of an electric motor to meet a specific power transmission need and then to select one from those offered by manufacturers. It has been compiled as part of a series, which covers typical elements of a system.

In this guide only conventional power transmission motors will be considered. This covers AC and DC motors between about 30 watts and 30 kilowatts. Other motors will be dealt with in other guides. The guide looks at the selection procedure, factors affecting motor selection, and motor selection and specification.

[Description and screenshot taken from the SEED Curriculum for Engineering Design page for this guide. (c) The Design Society used under the terms of their (CC BY-NC-SA 3.0) license.]

The purpose of this guide is to enable the user to determine the attributes required of a gearbox to meet a specific power transmission need and then to select an appropriate gearbox from those offered by manufacturers. It has been compiled as part of a series which covers typical elements of a system. It is not concerned with the detailed design of a gearbox which will be covered in other guides in this series. Before embarking on the selection procedure it is necessary to ensure that the need for a gearbox, has been carefully considered. The guides at higher levels in the Mechanical Power Transmission Series provide assistance in this process. The successful selection of a suitable gearbox is the result of matching the requirements of the power transmission system with one of the range of boxes offered by the manufacturers. Thus information about the system and information about available hardware is necessary.

The guide looks at the selection procedure, types of gearbox and their characteristics, general characteristics, factors affecting gearbox selection, and manufacturers.

[Description and screenshot taken from the SEED Curriculum for Engineering Design page for this guide. (c) The Design Society used under the terms of their (CC BY-NC-SA 3.0) license.]

You can use this guide to determine what kind of a seal will meet your needs and then to select a seal from those offered by manufacturers. If you are not very familiar with the standard types of seal available from stock then review the section on standard seal types available from manufacturers. Reference should be made at every stage of the selection process to the Product Design Specification (PDS) for the system (all the relevant factors should be described in a well written PDS). The characteristics of seals available “off the shelf” often constrain the design of the system components that require the seal so be prepared to change their design to match a manufacturer’s seal.

The guides looks at how to: specify the environment and operating conditions, specify the performance of the seal, select the type of seal required, select the material for the seal, choose a seal from a manufacturer’s catalogue, review your choice of seal. There is also a list of seal manufacturers.

[Description and screenshot taken from the SEED Curriculum for Engineering Design page for this guide. (c) The Design Society used under the terms of their (CC BY-NC-SA 3.0) license.]

This guide gives information on how to design a shaft when fluctuating loads are to be considered. It gives details on how to: Determine External Loads; Choose Preliminary Dimensions; Identify Critical Shaft Sections; Determine Stresses; Combine Stresses; Choose Failure Criterion; Choose Material and Material Properties; Determine Fatigue and Safety Factors; Compare Stresses and Strength; Specify Shaft. This guide should be used in conjunction with the guide, How to design a Shaft for Strength and Rigidity. There is also a list of suggested further reading.

[Description and screenshot taken from the SEED Curriculum for Engineering Design page for this guide. (c) The Design Society used under the terms of their (CC BY-NC-SA 3.0) license.]

This guide gives information on how to design a shaft for strength and rigidity. It gives details on how to: determine the loads on the shaft; choose provisional dimensions for the shaft; identify critical sections; calculate internal forces and moments; introduce safety factor; choose material; calculate deflection; compare factored stresses with strength of material; specify shaft.

References are also provided.

[Description and screenshot taken from the SEED Curriculum for Engineering Design page for this guide. (c) The Design Society used under the terms of their (CC BY-NC-SA 3.0) license.]

You can use this guide to determine the attributes required of a rolling element bearing to meet a specific power transmission need and then to select one from those offered by manufacturers. If you are unfamiliar with rolling element bearings then review the page on Bearing types and characteristics. This guide comes in the following sections:
1. Introduction 2. Specify the factors that determine the choice of the bearing 3. Decide the required type of bearing 4. Determine the equivalent load and speed 5.  Determine the equivalent bearing life 6. Determine the dynamic load rating 7. Select a bearing and check.

Other information includes details of bearing manufacturers, references and standards, and a list of the notation and symbols used in the guide.

[Description and screenshot taken from the SEED Curriculum for Engineering Design page for this guide. (c) The Design Society used under the terms of their (CC BY-NC-SA 3.0) license.]

This guide gives an insight into the types, terminology used, selection procedure and uses of standard chain drives. The most common applications for chains drives are discussed and a simplified strategy is given to help the infrequent user select an appropriate chain system using information from a manufacturer’s catalogue. Chain drives are an important and widely used type of mechanical element. They have two major uses, that is, for power transmissions and for materials handling purposes on conveyors. In addition, specific types of chain are used for supporting loads and for lifting purposes. As a transmission, chain drives can operate efficiently at high loads and they may be used where precise speed ratios are required. Selecting the best type of transmission drive will depend on the specific requirements of the application. Certainly, chain drives are widely used throughout mechanical engineering and, therefore, deserve to be very seriously considered at the preliminary stages of design.

This guide includes the sections: Preliminary Selection, Types of Chain, Factors Affecting Roller Chain Selection, Lubrication of Chains, Roller Chain Terminology, Standard Sizes, Chain Power Ratings, Chain Nomenclature, Roller Chain Selection Example,  and Chain Costs. Other information includes suggested further reading and details of leading chain manufacturers.

[Description and screenshot taken from the SEED Curriculum for Engineering Design page for this guide. (c) The Design Society used under the terms of their (CC BY-NC-SA 3.0) license.]

The purpose of this guide is to enable the user to determine the attributes needed of a planar mechanism to meet a specific combination of output requirements and then to select the appropriate type. It has been compiled as part of a series which covers typical elements of a system. In this guide only planar mechanisms driven by “constant” velocity rotating input are considered. Other aspects of mechanism design will be dealt with in subsequent guides. The guide gives information on the types of planar mechanism and factors influencing type selection. It also has a list of specialist manufacturers and an appendix with information on direct electrical drives.

[Description and screenshot taken from the SEED Curriculum for Engineering Design page for this guide. (c) The Design Society used under the terms of their (CC BY-NC-SA 3.0) license.]

You can use this guide to determine the attributes required of a belt drive to meet a specific power transmission need and then to select a drive from those offered by manufacturers. The successful selection of a suitable belt drive is the result of matching the requirements of the power transmission system with one of the range of belt systems offered by the manufacturers. Thus, information about both the system and the hardware available is necessary, and the selection process entails six consecutive stages:

1. Gathering information about the system
2. Deciding on influential factors
3. Establishing limits of acceptability for factors
4. Collating information from manufacturers
5. Selecting a suitable element
6. Seeking follow-up advice

The guide also has information on how to specify the environment and operating conditions and the performance of the belt drive, how to select the belt drive required, and how to install the belt drive. Other information includes details of belt drive types currently available, power ranges, belt drive manufacturers, and suggested further reading.

Reference should be made at every stage to the Product Design Specification (PDS) for the system (all the relevant factors should be described in a well written PDS). Note that, before embarking on the selection process, you should ensure that the need for a belt drive, as distinct from other forms of drive, has been carefully considered. The Guides at higher levels in the Mechanical Power Transmission Series provide assistance in this process.

[Description and screenshot taken from the SEED Curriculum for Engineering Design page for this guide. (c) The Design Society used under the terms of their (CC BY-NC-SA 3.0) license.]

You can use this guide to select standard gears from catalogues. If you are unfamiliar with standard gears first review the sections on standard gears and gear terminology. Gears can either be obtained as standard components from a manufacturer’s catalogue or alternatively specially designed and manufactured. Smaller sized gears, especially instrument gears, tend to be more readily available from catalogues and larger, less used gear types tend to be produced as specials; usage is claimed by leading manufacturers to be approximately equally divided. For practical reasons, gear catalogues tend to display only geometric and materials data of stock gears rather than specific operational information. This is because functional behaviour will vary with an application and so it is not feasible to give comprehensive data covering all operational conditions within a catalogue for a complete product range. The guide describes a practical approach which ensures that gears selected from a catalogue are technically suitable for a specific application. Technical considerations usually produce a number of viable alternatives so cost may well be the decisive factor influencing the final selection.

The guide details how to: establish the requirements; choose the number of teeth, type and material for the gears; calculate the pitch-line velocity and tooth bending stress; select suitable gears by considering materials and cost. Other information includes notation for calculations, a worked example, details of gear manufacturers, and a bibliography.

[Description and screenshot taken from the SEED Curriculum for Engineering Design page for this guide. (c) The Design Society used under the terms of their (CC BY-NC-SA 3.0) license.]

The purpose of this guide is to draw together the fundamental principles, which should be considered in the design of a rotary power transmission system so that it will perform effectively as an entity. If you are unfamiliar with the design of rotary power transmission systems then review the section on concepts and definitions. The selection of individual system elements e.g. motors, gearboxes etc. is presented in other Guides in this series. The four sections of this guide are: consider the load on the system, match the load to the supply, consider other characteristics of the system components, and find real system elements.

[Description and screenshot taken from the SEED Curriculum for Engineering Design page for this guide. (c) The Design Society used under the terms of their (CC BY-NC-SA 3.0) license.]

The aim of this guide is to provide procedures to enable the user to design a bolted connection where the dominant load acts parallel to the axes of the bolts making the connection (and therefore perpendicular to the connecting faces of the parts which constitute the joint). The guide provides sufficient additional data to enable the threaded elements to be selected and specified. Typical joint configurations where the threaded fasteners are in tension/bending, simple tension or shear are shown in the following figures:

Figure 1. Types of Bolted Connection covered by this Guide

Two approaches are included. The first covers “statically loaded joints” and the second “dynamically loaded joints”. The first approach is essentially a simplified version of the second and can be adopted when the variation of the axial load at the joint in service can be regarded as negligible and the number of times that the axial load is applied to the joint throughout its working life is less than 105 applications. The guide assumes that the component parts being connected are sufficiently rigid so as to not subject the threaded fasteners to bending stresses when the joint is being tightened or when it is under load in service. The guide does not consider the design of threaded connections where the threaded fastener is subject to lateral shear – clevis joints for example. In these cases, the threaded fastener is subject to high bearing stresses on its diameter and, invariably, bending stresses accompany the lateral shear stress. These situations are considered to be outside the scope of this guide.

Section 2 looks at the limits of the guide in greater depth. The guide advises in general terms on aspects of good practice relating to the positioning of fasteners in a joint. The number and position of fasteners to be used in a given situation tends to be influenced by other features of the design work being undertaken and there is a wide variety of possibilities which are difficult to categorise in a brief guide such as this. The symbols and nomenclature used throughout the guide are defined as they occur. No derivations of equations are presented; such derivations are available for those who require them in the Bibliography at the end of the guide.

Section 3 covers the selection of bolted connections which are statically loaded. This enables the user to design safe connections for static loading using a flow chart approach. Section 4 gives the necessary background and equations for determining the load distribution and corresponding stress levels imposed on the component parts of a joint subjected to fatigue loading. It also includes a table of screw thread strength reduction factors, which should be used in conjunction with the other strength reduction factors used in designing against fatigue. A second flow chart is included, giving the reader a step-by-step procedure for the safe design of bolted joints capable of sustaining fatigue loading. Section 5 examines and discusses the relationship between applied torque and induced load and the distribution of stress in normal threaded fasteners. Section 6 deals with ISO grading of threaded connector materials. Section 7 looks at the common thread system as well as touching on past systems. Section 8 shows how to select fasteners with the best characteristics for many applications.

[Description and screenshot taken from the SEED Curriculum for Engineering Design page for this guide. (c) The Design Society used under the terms of their (CC BY-NC-SA 3.0) license.]

This guide aims to: determine the optimal dimensions of a cam mechanism to produce a given motion and satisfy the kinematic constraints imposed by limiting pressure angle and profile curvature as well as the artificial limitations associated with a particular application, such as space restrictions; determine the spring force needed for force closure; use cam design to illustrate the principles of preparing and applying design data for solving multi-variable problems which do not yield readily to mathematical analysis. It is recommended that the ‘Unit Design – Cam Mechanisms‘ guide be read first. See the References Section for further citations, including software. This supplement is intended to provide background information for tutors using SEED ‘Unit Design – Cam Mechanisms‘ guide for undergraduate design assignments. It includes additional explanations and figures, supplies cross-references, identifies manufacturers and outlines possible assignments. It is assumed that the students have access to micro-computers and can use a suitable spreadsheet package.

The guide includes the sections:

• The Cam Mechanism
• Cam Laws
• Forces on the Follower
• Pressure Angle
• Profile Curvature – Undercutting
• Design Procedure for Optimum Cam Size
• Validation
• The Spreadsheet
• General Approach to Cam Design
• Outlines for Assignments

[Description and screenshot taken from the SEED Curriculum for Engineering Design page for this guide. (c) The Design Society used under the terms of their (CC BY-NC-SA 3.0) license.]

The purpose of this guide is to enable the user to determine the optimum dimensions and to specify the sprung force closure of a disc cam mechanism, which produces the required output motion, whilst satisfying the kinematic constraints imposed by the maximum pressure angle and profile curvature. Cam mechanisms are used to convert a simple input motion, such as a shaft rotating at nominally “constant” speed, into a complex output motion. The output motion from cam mechanisms is versatile as the displacement, velocity and acceleration are all controlled accurately; it can also include stationary periods. Each movement can be specified independently of the remainder of the operating sequence. Besides the familiar application of the cam-operated valves of petrol engines the mechanism is used in textile manufacture, automatic assembly, wrapping machinery and many special-purpose devices. This guide assumes that the procedure given in SEED Design Guide “Planar Mechanisms” has been followed. Books and commercial software packages, which cover the design, dynamics and strength of most configurations of the cam mechanism, are cited in “Sources of Information“.

The guide includes the sections:

• Prepare the Timing Chart
• Construction and Operation
• Terminology
• Dimensions and Notation
• Output Motion
• Non-Dimensional Parameters
• Cam Laws
• Cam Law Selection
• Minimum Cam Size From Kinematic Constraints
• Space Constraints and Configuration
• Application of a Spreadsheet
• Optimum Cam Size
• Force Closure
• Dynamic Design

[Description and screenshot taken from the SEED Curriculum for Engineering Design page for this guide. (c) The Design Society used under the terms of their (CC BY-NC-SA 3.0) license.]

The purpose of this procedural guide is to enable the user to determine the attributes of an appropriate shaft coupling for a mechanical power transmission system and hence to select one from a manufacturer’s catalogue. It has been compiled as part of a series which covers typical elements of a system. It deals with the coupling of two shafts which are co-linear, or very nearly so. It does not cover shaft-hub connections, clutches, universal joints or torque limiters. The guide gives details of the selection procedure, types of shaft coupling and misalignment and factors affecting coupling selection.

[Description and screenshot taken from the SEED Curriculum for Engineering Design page for this guide. (c) The Design Society used under the terms of their (CC BY-NC-SA 3.0) license.]

Connections can either be obtained as standard components from a manufacturer’s catalogue or alternatively specially designed and manufactured. Smaller sized connections tend to be more readily available from catalogues and larger, less used types tend to be produced as specials. This guide is only concerned with the selection and subsequent use of standard components. It enables the user to specify the attributes of a connection to meet specific needs and then to select a connection from those offered by manufacturers. The types of connections most commonly used are illustrated and discussed. The guide takes a practical approach that ensures the technical suitability of connections for specific applications. Technical considerations usually indicate a number of viable possibilities so cost may well be the decisive factor influencing the final selection.

The guide looks at whether your connection is really necessary, common connections, how to determine the operating conditions, how to specify the factors that influence the choice of connection, the performance required, and the type of connection. There is also a worked example, a list of major manufacturers, a bibliography and suggested further reading, and notes on the design of Shaft-Hub Connections.

[Description and screenshot taken from the SEED Curriculum for Engineering Design page for this guide. (c) The Design Society used under the terms of their (CC BY-NC-SA 3.0) license.]

[Description and screenshot taken from MIT OCW page for this course. (c) MIT used under the terms of their CC-NC-SA license.]

This course is a first subject in engineering design. A major element of the course is design of a robot to participate in a challenge that changes from year to year. This year, the theme is cleaning up the planet as inspired by the movie Wall-E.

From its beginnings in 1970, the 2.007 final project competition has grown into an Olympics of engineering. See this MIT News story for more background, a photo gallery, and videos about this course.

After taking this course students should be able to: generate, analyze, and refine the design of electro-mechanical devices making use of physics and mathematics; describe and list uses in mechanical systems of common machine elements including fasteners, joints, springs, bearings, gearing, clutches, couplings, belts, chains, and shafts; apply experimentation and data analytic principles relevant to mechanical design; and communicate a design and its analysis (written, oral, and graphical forms).

Special software is required to use some of the files in this course: .zip, .sldprt, .xls, .swj, .sldasm, .rpt, .xlo, .igs, .rm, .ord, and .dxf.

[Description and screenshot taken from MIT OCW page for this course. (c) MIT used under the terms of their CC-NC-SA license.]

This is an advanced course on modelling, design, integration and best practices for use of machine elements such as bearings, springs, gears, cams and mechanisms. Modelling and analysis of these elements is based upon extensive application of physics, mathematics and core mechanical engineering principles (solid mechanics, fluid mechanics, manufacturing, estimation, computer simulation, etc.). These principles are reinforced via (1) hands-on laboratory experiences wherein students conduct experiments and disassemble machines and (2) a substantial design project wherein students model, design, fabricate and characterize a mechanical system that is relevant to a real world application. Students master the materials via problems sets that are directly related to, and coordinated with, the deliverables of their project. Student assessment is based upon mastery of the course materials and the student’s ability to synthesize, model and fabricate a mechanical device subject to engineering constraints (e.g. cost and time/schedule).

[Description and screenshot taken from MIT OCW page for this course. (c) MIT used under the terms of their CC-NC-SA license.]

Lecture Archive
Microprocessors & Labs
Power Screw & Fastner
Bolt & Preload 1
Bolt & Preload 2
Fatigue Loading 1
Fatigue Loading 2
Rolling-Contact Bearings 1
Rolling-Contact Bearings 2
Gears 1
Gears 2
Gears 3
Gears 4
Gear Train 1
Gear Train 2
Gear Force
Review for Exam
Motors
Feedback Control
Electronics Components