It is known as the strength of the material. There are two objectives, The first is to determine the stress that acts on the surface of volume elements of critical points of loaded structures. Secondly, To aid in the design and analysis of the structures, it also establishes equivalent stresses based on strength requirements linked to potential failure modes.

Also, A field of study in engineering and physics called mechanics of materials. It is an essential area of study for engineers and is necessary for the design and analysis of mechanical parts and structures. 

These are some essential ideas and notions in material mechanics.

Stress:

Stress is a measurement of a material's internal resistance to deformation in the presence of an external force. It usually has units of Pascals (Pa) and is represented as force per unit area. The stress calculation formula as below. 

There are a few types of stress.

Tensile Stress:

Tensile stress is the stress that develops when an axial load tries to elongate or stretch a material. It is computed by dividing the applied force by the area of the cross-section.

Compressive Stress:

An axial load that attempts to compress or shorten a material will cause compressive stress, which is the opposite of tensile stress.

Shear Stress:

Shear stress is the important parameter in various fields. Shear stress is an internal resistance within a material when subjected to forces that cause one layer or portion of the material to slide or deform relative to an adjacent layer.

Mathematically, shear stress is defined as:

τ = F / A

Where:

τ (tau) is the shear stress in pascals (Pa) or other appropriate units.

F is the force applied parallel to the material's surface.
A is the cross-sectional area over which the force is applied.

Bearing Stress:

Bearing stress occurs when two materials are in contact, and the force is applied perpendicular to the surface. It is the force divided by the contact area.

Strain:

Strain is a measure of the deformation or change in shape that a material undergoes when subjected to an external force or load. It is frequently described as the variation in length or shape from the initial length or shape. Dimensionless, strain is classified into two types: shear strain, which comes from shear stress, and axial strain, which comes from normal stress.

Depending of the nature application, there are different types. Such as compressive strain happens when applying compressive forces, tensile strain occurs when applying stretching forces, and simple shear strain occurs when forces act parallel to each other but in opposite directions, causing a material to deform without changing its volume.

Young's Modules:

Under axial load, a material's resistance to elastic deformation, or reversible deformation, is expressed by its Young's modulus (E). It uses the relationship between stress and strain to describe the stiffness of a material.

Hooke's Law:

This is described that linear relationship between the strain of the material (deformation) and applied force inn elastic region of the material. , it asserts that stress and strain are directly proportionate.

Where,

F is Spring Force

k is spring constant

x is spring stretch or compression

Yield Strength:

The point at which a material experiences permanent deformation or yielding is known as the yield strength. This is in contrast to the ultimate strength. A material's ultimate strength is the highest stress it can bear before failing.

Yield strength is relevant for ductile material. In contrast, brittle material is not showing the significant plastic deformation before facture. In brittle materials, there is no distinct yield point or yield strength. Instead, they have a linear or nearly linear elastic region in their stress-strain curve up to the point of fracture.

Factor of Safety:

A structure or component's ability to support loads with a margin of safety is determined by using the factor of safety in engineering design. It is the ratio of the material's ultimate strength to the highest load that can be anticipated.

Torsion:

When an object is subjected to a torque or twisting force, it will twist or rotate, a phenomenon known as torsion in mechanics. An essential idea in mechanics and engineering, torsion is especially important when examining how structural elements that undergo twisting loads, such as beams, shafts, and other components.

A material deforms when it is subjected to torsional force, and this deformation is characterized by a change in rotational angle. Shear strain which is defined as the change in angle per unit length of the material, is a notion that describes this deformation. Shear stresses in the material as a result of torsional deformation are what cause the material to resist an applied torque.

The fundamental equation that relates these parameters in the context of torsion is:

τ = T * r / J

Where:

τ is the shear stress,

T is the applied torque,

r is the radial distance from the center of rotation (distance from the axis of rotation to the point of interest)

J is the polar moment of inertia.

Bending:

A combination of axial and transverse loads can cause a structural element to bend.

There are two types of bending,

                                                     

Flexural Bending (or simply Bending):

The most frequent kind of bending is called flexural bending, which happens when a material or structural element is subjected to a load or force that is delivered perpendicularly, causing the material or structural element to deform and curve. Beams, rods, and sheets that bend are common examples.

Shear Bending (Torsional Bending):

Shear bending, sometimes referred to as torsional bending, is the result of rotating or twisting forces causing a material to deform in a curved direction.

The formula for bending,

σ = (M * c) / I

Where:

σ is the bending stress

M is the bending moment

c is the distance from the neutral axis to the outermost fiber of the material

I is the moment of inertia of the material's cross-sectional shape.

In conclusion, The design, analysis, and safety of mechanical components and structures in many engineering specialties, including civil, mechanical, and aerospace engineering, rely significantly on the concepts of materials mechanics. Engineers utilize these principles to ensure that materials and constructions are strong enough to handle expected loads and perform as intended.

Design

November 02, 2023

Computer-aided design is denoted as CAD and Computer-Aided Manufacturing is denoted as CAM and those two are related to two different classes of application programs which support the design, build and analysis of simple or complex product assemblies, and plants. 20 years ago, these two programs were introduced to the market. At that time, those programs were expensive and difficult to learn. As an example, the McDonald-Douglas CAD program which was used to design aircraft by Boeing was more expensive at half a million dollars a highly powerful workstation computer was needed and lots of time had to be spent to learn it. However, with recent advanced technologies and superpowers, fast personal computers, high-quality friendly GUI interfaces, and sufficiently developed calculation algorithms, CAD/CAM can be used in-house manner for engineering and manufacturing applications. Therefore, engineers can design without support from the drafter.

Computer Aided Manufacturing (CAM) is based on computer numerical Control (CNC) with computer software tools which are pre-programmed to aid in moving factory tools and machinery. G-code can be identified as the most widely used CNC programming language. Computer Aided Design (CAD) is used to generate electronic files to print, for manufacturing purposes and machining operations. The productivity of the designers, and engineers and the quality of the designs can be enhanced using CAD software. CAD software is a valuable technical platform for both engineers and designers who are working in a range of industries such as automotive, aircraft, agriculture, etc. although, CAD and CAM are two specific areas, both software tend to be used together as CAD/CAM.

CAD originated in three separate sources which are to automate the drafting process, the testing of designs by simulation, and to facilitate the flow from the design process to the manufacturing process using numerical control (NC) technologies. The biggest advantage was that time-saving in computer modelling over conventional drafting methods and, models can be changed or updated by changing the parameters of the model. Computer modelling software was used in high-tech industries such as aerospace, military and semiconductors in the early times. After that, computer numerical control technologies were widely used in many applications in of 1960s and this was the initial source for linkage between CAD and CAM. CAD/CAM integration between design and manufacturing stages which CAD/CAM-based production process.

Usage of CAD/CAM rapidly increased after the early 1970s for making silicon chips and microprocessors on a large scale to design affordable computers. Therefore, the price of the computers continuously declined and performance has improved. Also, large-scale firms frequently used CAD/CAM for large-scale mass production techniques. Some manufacturing processes were controlled using several computers but were not strictly called CAM due to geometric parameters that have not been taken as control data.

The history of CAD

Computer-aided design software is used by engineers, and designers in various industries to design various products such as bridges, roads, aircraft, cloths, mobile phones, ships, TVs, etc. CAD software history began with “The Elements” which Euclidian geometry was written by mathematician Euclid Alexandria, in 350 B.C.

The initial term “computer-aided design” was introduced by Douglas T. Ross in the early 1950s when he was working as a researcher at the Massachusetts Institute of Technology (MIT) to develop military radar technology and computer display systems. Before exploring CAD, Automatically Programmed Tools (APT) which is used to create Automated Engineering Design (AED) has been developed by Ross. After that, a discussion was started with MIT to expand technologies with earlier experiences.

The initial user of the CAD was Patrick Hanratty at the General Motors Research Laboratories. The Design Automated by Computer (DAC) was developed as the first CAD system with interactive graphics. The first commercial CAD/CAM code was developed by integrating numerical control programming software named PRONTO in 1957. Therefore, Patrick Hanratty was called as the father of CAD/CAM. The first true CAD software was the Sketchpad which was developed by Ivan Sutherland in the early 1960s as a result of his Ph.D. thesis at MIT.

The history of CAM

Computer-aided manufacturing (CAM) technology has been referred to with numerical control (NC) software which is used to create G-code. G-codes are used to operate the computer numerical control (CNC) machine tools to manufacture parts and products. Computer-generated design or CAD drawing is used to take information to create instructions to control the movements of an automated tool. Computer-aided manufacturing software enhances the production and manufacturing process.

Computer-aided manufacturing processes began to develop in the 1950s and also were used in the 1970s. Using CAM software, designs can be directly imported into CAM to produce them while providing only raw materials and instructions such as feed rate, speed and dimension. NC machines were used for CAM technology in the early 1950s and highly developed CNC machines are available recently.

The first NC machine was developed by John T Parsons in 1949. The idea to develop a punch card machine was initiated while trying to find ways to build helicopter rotors to speed up the manufacturing process. However, the developed one was not properly working and tried to develop further under US Air Force funds. Further, the first NC prototype was developed with the aid of the Servomechanism Laboratory at MIT.

CAD/CAM History in the apparel industry

The first label-sewn creation machine for garments was designed by Charles Frederick in 1858, the 19^th century with the modern fashion industry beginning. Initially, labels were drawn using pencil and paper. When changing society and culture, demand for labels and label variations increased and the process was challenged. The reason behind this was that styles and customer tastes were frequently changed in the market. Therefore, alternative solutions were tried to aid in enhancing the design and manufacturing process.

CAD was applied when doing designs using computers by incorporating it into the apparel industry. Currently, CAD programs are frequently used and essential for fashion designers and garment factories. The function of CAD in the apparel industry is pattern making, making markers, grading patterns virtual test fitting etc. CAD tools also enhance productivity and reduce design time.

Advantages

Designs can be changed without erasing and redrawing

Due to the “zoom” feature of CAD, the model can be magnified and inspected as necessary by to designer

Due to the three-dimensional modelling feature, the model can be rotated on any axis

Machine capabilities can be improved

Material wastage can be reduced using CAD/CAM

Client Accessibility is improved

Save time

Easy to share and less design effect

High-quality and reliable finish products can be manufactured using CAM, due to fewer human errors

Disadvantages

Due to computer-related tasks, data may be lost due to sudden failure of the devices

Initial establishment cost is high

Due to the use less workers, traditional skills will be lost due to increasing unemployment

Maintenance and update cost is high

Design Manufacturing

October 26, 2023

Conventional or Traditional Design

Conventional design is done according to the known set of parameters, which someone has done, found, invented or innovated. These cases are well-known principles that are established and these can be used to do similar designs while only changing the capacities, power, strength, size, and other mechanical and performance parameters.

For example as below,

Gearbox design

Die design

Mould design

Also, the standard machine element designs can be considered traditional designs. These are already design concepts and we can use them to design new ones by changing the design parameters.

For example as below,

Gears

Belts

Pulleys

Shafts

Springs

There are a lot of handbooks in mechanical engineering to do traditional design and we can follow these guidelines and catalogs. Also, there are lots of software to inbuilt traditional elements.

Innovative design

The novelty is the important thing to stay in the competitive market to fulfil user demand. These upgrading changes can be identified as design by evaluation. Innovative design is a process of identifying potential requirements and developing or modifying the product or ideas by using creativity and new technologies. Novelties are in slowly moving paths. A novel concept or product is innovated with a sound research approach and this innovated item will be improved gradually by scientific validation and research. These findings are used to further research whether they are valuable or not. Physically realizable, economically worthwhile, and financially feasible are the important characteristics of remarkable inventions which are created by inventors.

A few examples are,

Acoustic Wave Separation

Solar power-generating windows which are fully transparent

An absorber design using natural hyperbolic material for harvesting solar energy.

Hybrid simulation of thunderstorm outflows

Adaptive Innovation

Adaptive innovation is one of the common methods that can be used to develop an innovative concept or product nowadays. Several development inventions in other technologies or application fields are combined to develop a combined concept or product with lots of advantages. Adaptive innovation is considered as ideas, testing, thinking, and pushing again and again. The different fields or applications are subjected to development using adaptive innovation. These adoptions result in replacing the existing traditional method and making some tasks easy. As an example, image processing technology initially was introduced for satellite imagery, however, it has adapted to many different fields nowadays face detection (security systems), quality control methods, medical imaging, etc.

Adaptive innovation mainly helps with problem-solving and the creativity model aims to increase collaboration and reduce conflict. In adaptive innovation, six areas of never-ending, persistent work for Adaptive Innovation emerge,

Trends & Needs

Discoveries

Insight

Innovation

Invention

Products & Services

Inventive Innovation

This is an engineering term related to the invention. Inventive innovation can be identified as a major step forward on the technology front or it can be a novel product a completely new one or an earlier non-existent product. Also, concepts or methodology can be identified as inventive innovations. Device or originate which is known as to invent in a novelty of a new kind or nature hitherto unknown. Thus, inventive innovation is incorporating a change hitherto unknown.

Frist electrical Build

Frist generator

First Motor

First Steam engine

Wheel

Laser

Semiconductor Chip

Design

October 24, 2023

SolidWorks simulation is a design analysis tool based on a numerical technique called Finite Element Analysis (FEA). This is used to solve problems described by a set of partial differential equations. These kinds of problems can be found in various engineering disciplines, such as machine design, fluid dynamics, and others.

In mechanical engineering, FEA is widely used to solve problems related to structural, vibration, and thermal problems. There are other numerical solution analysis tools, such as the Finite Difference method, Boundary Element Method or Finite Volumes Method. However, FEA became a common tool due to its versatility and high efficiency. The FEA method can be used to solve problems ranging from very simple to very complex. Mechanical design engineers use often it in the design stage. The basic phases in each FEA project are always the same, regardless of the project's complexity or area of application. The geometric model is the starting point for any analysis. In SolidWorks, a SolidWorks part or assembly is a geometric model containing applicable material properties, loads, and restrictions.

The model is discretized (meshed) for the analysis. The geometry is divided into relatively small and simple-shaped entities known as finite elements throughout this procedure. The elements are referred to be finite to indicate that they are not infinitesimally small, but rather reasonably small in respect to the overall model size.

Each FEA application requires three steps,

Preprocessing:

The type of analysis, material properties, loads and restraints are defined and the model is split into finite elements.

Solution:

Computing the desired results.

Postprocessing:

Analysis of the results.

There are four main steps in the FEA methodology,

Building the mathematical mode:

The geometric shape is represented by a SolidWorks part or assembly. Then model is meshed into correct and reasonably small, finite elements. This meshing process is very important because good mesh geometry provides the correct solution for the data of interest, such as stress, displacements, and etc.

Defeaturing:

This is called simply the geometric model by removing or suppressing features which are insignificant to analysis. As an example, removing thread features, and logos.

Idealization:

The process of reducing a real structure to a collection of finite elements. At its most basic, the operation would consist of a single CAD-generated geometric model that is fully meshed in a single operation.

Clean-up:

This is required but not always. This process is used to maintain the higher quality requirements. CAS quality-control tools can be used to check for any problems. Such as multiple entities or sliver daces.

Build a Finite Element Model

The geometric model is split into finite elements through a process of discretization, better known as meshing. Discretization visually manifests itself as the meshing of geometry. However, loads and supports are also discretized and, after the model has been meshed., the discretized model loads and supports are applied to nodes of the finite element mesh.

Solve the Finite element Model

After completing the finite element model, a solver in Solidworks simulation is used to get the desired results.

Analysis Results

This is the most difficult step in FEA. There are a lot of details in the results in many formats.

Stress

Strain

Displacement

Factor of Safety

Natural Frequency

Temperature

Errors in FEA

The process of the FEA introduces unavoidable errors while creating mathematical models and discretizing. such as modelling errors (idealization errors) in the formulation of mathematical models discretization errors in the meshing process and numerical errors in solutions.

Only discretization error applies to FEA. Therefore, discretization errors can be controlled using FEA methods. modelling errors can be controlled by correcting the model before the FEA. Solution errors are difficult to control because they come from the solver.  

 

 

Design

October 21, 2023