Basics of Aircraft Structures

Aircraft Structures:

• Major criteria for the design of aircraft structures is structural safety with minimum weight, which comprises of thin load bearing skins, frames, stiffeners, spars, made of light weight, high strength, high stiffness materials.
• Aircraft structures are designed to utilize each part to its full capacity. Leads to shell-like (monocoque) & hardened shell (semi-monocoque) structures.

Categories of Aircraft:

1. Fixed-wing Airplane
2. Rotor-craft
3. Lighter than Air Vehicles
4. Glider

A large portion of the aircraft working today are made with lightweight yet solid aluminum, with most fresher aircraft being made of advanced composites.

Basic Components of Aircraft:

1. Fuselage
2. Wings
3. Tail
4. Power Plant
5. Landing Gear

Major aircraft components are included essential basic structural elements, each of which is intended to take a particular kind of load.

1. Fuselage:

• The fuselage is the main body of the airplane that carries the Crew and the Payload.
• the payload being travelers, load, fuel and weapons.
• Fuselage structures can be of monocoque development, or of semi-monocoque development.
• Incorporates various access entryways, inspection plates, landing wheel wells, and different openings

   

   2. Wings:

• The Wings give the Lift to an Aircraft.
• Wings are subjected to High Stress because of Aerodynamic Forces and in addition the Weight of the Engines and response loads from Landing Gears.
• The external surface of the wing originally made of fabric, modern aircraft use aluminum or composite materials because of their lightweight and rust proof properties.

    

   3. Tail:

• The empennage, normally called the tail assembly, is the rear section of the plane body. Its main objective is to stabilize the airplane. 
• The settled parts are the horizontal stabilizer and the vertical stabilizer, or balance. 
• The front, settled segment called the horizontal stabilizer and is utilized to keep the flying machine pitching up or down. 
• The vertical tail structure is isolated into the vertical stabilizer and rudder. The front segment is known as the vertical stabilizer and is utilized to keep the flying machine yaw forward and backward. 

   

 4. Power Plant:

• Aircraft power plants are essentially motors, and they help planes and helicopters to take off. 
• A unit which converts chemical energy contains in the fuel to thrust force, this force is vital for the movement of the plane and lift creation. 
• With the piston engine, the propeller is utilized to change over the torque on the engine shaft being thrust. 

   

   5. Landing Gear:

• Aircraft landing gear bolsters up the whole weight of an airplane amid landing and ground. 
• They are joined to primary structural members of the aircraft. 
• It will be of skis type for snow, pontoon type for water, and for ground an amphibious aircraft with retractable wheels. 
• Kind of gear relies on upon the aircraft and its planned utilize.

A Beginners Notes on Aeroelasticity

Aeroelasticity:

Aeroelasticity is the subject that describes the interaction of aerodynamic forces on aircraft, inertia, buildings, surface vehicles etc for a flexible structure and the phenomena that can result.

• Aeroelasticity is not exclusively concerned with aircraft, the topic is also relevant for the design of structures for example, bridges, Formula 1 racing cars, wind turbines, turbo machinery blades, helicopters, and so on.
• Aeroelastic issues would not exist if airplane structures were perfectly rigid.
• Numerous imperative aeroelastic phenomena involve inertia forces as well as aerodynamic and elastic forces.

Applicable For:

1. Ships, Offshore Structures
2. Aero Structures
3. Civil Structures
4. More specially used to address issues related to flying vehicles

Dynamic Aeroelasticity:

Concerned with the oscillatory impacts of the aeroelastic interactions, and the primary area of interest is the potentially catastrophic phenomenon of flutter.

Phenomena including interactions of inertial, aerodynamic, and elastic forces. It deals with the body’s dynamic  reaction.

Phenomena including three type of forces:

1. Buffeting: Transient vibrations of flying machine auxiliary parts because of aerodynamic impulses delivered by wake behind wings, nacelles, fuselage cases, or different segments of the plane.
2. Dynamic Response: Transient reaction of airplane basic parts created by quickly connected burdens because of blasts, landing, weapon responses, sudden control movements, and moving stun waves.
3. Flutter: Dynamic instability happening for air ship in flight at a rate called flutter speed.

Static Aeroelasticity:

Considers the non-oscillatory impacts of aerodynamic forces acting on the flexible airplane structure. The adaptable way of the wing will impact the in-flight wing shape and thus the lift appropriation in a consistent move or in the uncommon instance of cruise.

Deals the static or steady response of a versatile body to a fluid flow. 

Phenomena including three type of forces:

1. Divergence: A static instability of a lifting surface of a flying machine in flight, at a rate called the divergence speed, where flexibility of the lifting surface assumes a key part in the instability.
2. Control System Reversal: A condition happening in flight, at a rate called the control reversal speed, at which the proposed impact of dislodging a given part of the control framework are totally invalidated by elastic deformations of the structure.
3. Load Distribution: Impact of elastic deformations of the structure on the conveyance of aerodynamic pressures over the structure.

Introduction to Digital Eleectronics

Digital Electronics:
Digital electronics is the electronics that handle digital signals – discrete bands of analog levels – rather than by continuous ranges as utilized in analog electronics. All levels within a band of values represent the same information state.

Series and Parallel Circuits

Circuit:

• In Electronics, a circuit is a way between two or more focuses along which an electrical current can be conveyed. It is a complete course of conductors through which current can travel.
• Circuits comprising of only one battery and one load resistance are very easy to investigate, however they are not regularly found in practical applications. Typically, we find circuits where more than two parts are associated together.

There are two basic types of Electronic Circuit:

1. Series Circuit
2. Parallel Circuit
3. Series Parallel Circuit: This is a combination of above both.

1. Series Circuit

• In series circuit, resistors are arranged in a chain, so the current has only single path to take. 
• The current is the same through every resistor. The total resistance of the circuit is found by just including the resistance values of the individual resistors.
• A series circuit has more than one resistor, charges must move in "series" first going to one resistor then the following.
• If one of the items in the circuit is broken then no charge will travel through the circuit, the reason is there is only one path. 
• Series Circuits are the least complex to work with.

2. Parallel Circuit:

• A parallel circuit has more than one resistor, charges can travel through any of a few ways.
• The current in a parallel circuit separates, with some flowing along every parallel branch and re-joining when the branches meet once more. The voltage over every resistor in parallel is the same. 
• In parallel circuit the resistors are arranged with their heads associated together, and their tails associated together.

Problem with Series Circuit:

• If u add more devices in the circuit, the current will go down since all the current go through each devices(resistor).
• If you remove a light bulb or one breaks down, the entire series is turned off.

Parallel Circuit - Pros & Con:

• In parallel circuit, adding ,more devices does not decrease the current.
• By breaking of one resistor, the rest won't affect.
• Current doesn’t stay the same for entire circuit, so energy is spent quicker.

Series Circuit - Voltage:

• Voltage is the electric equivalent of water pressure.
• The higher the voltage, the quicker electrons will course through the conductor.
• Every segment has resistance that causes a drop in voltage (decrease in voltage).
• Total Voltage = The whole of voltages over every series resistors.
• Voltage is decreased by every resistance.
 

Parallel Circuit - Voltage:

• A charge just goes through a single resistor. 
• Voltage drop over the resistor that it chooses to go through must equivalent the voltage of the battery.
• Total voltage = the voltage over every  individual resistor

Series Circuit - Resistance:

• Resistors – resists the stream of electrical current.
• Expanded resistance will lessen the rate at which charge flows.
• Total Resistance = Sum of all resistors in the series.
• Total resistance will go up because all of the current must go through every resistor.

Parallel Circuit - Resistance:

• Resistors included one next to the other.
• Since the circuit offers two equal pathways for charge flow, just 1/2 the charge will choose to go through a given branch.

Series Circuit - Current:

• Current is the amount of charge, like flow of water.
• A current can't just vanish (show up), since only one path if some electrons flow through R1, then they need to keep coursing through R2 and R3.
• Use Ohm's law to discover current using resistance and voltage

Parallel Circuit - Current:

• ALL ways are utilized, in any case, the charge divides up into all branches. 
• One branch can have more current than another  branch, depends on resistance in branch.
• Total current = sum of current in every path.

Conclusion:

- In a series circuit, all components are associated end-to-end, framing a single path for electrons to flow.

- In a parallel circuit, all parts are associated over each other, shaping precisely two sets of electrically common points.

- A “branch” in a parallel circuit is a path for electric current shaped by one of the load components.

Ohm’s and Kirchhoff's Laws

Resistors:

• A resistor is a circuit component that dissipates electrical energy (usually as heat).
• Real-world devices that are modeled by resistors: glowing lights, warming components (stoves, radiators, and so on.), long wires.
• Parasitic Resistances: Many resistors on circuit diagrams model undesirable resistances in transistors, motors,etc.
• Resistance is measured in Ohms.

Ohm's Law:

• Ohm's law, named after Mr. Georg Simon Ohm, who defines the relationship between power, voltage, current and resistance.
• The voltage across a resistor is directly proportional to the current flowing through it.

                 - Conductor is also known as resistor.

                 - An ideal conductor is a material whose resistance does not change with temperature.

                                  Voltage = Current * Resistance

                                            V = I * R

Importance of  Ohm's Law:

• Defines the relationship between power, voltage, current and resistance.
• These are the very basic electrical units we work with. The principles apply to a.c., d.c. or radio frequency. 

Ohm's Law Formula's:

• For Voltage: E (volts) = I (current) * R (resistance).
• For Current: I (current) = E (volts) / R (resistance).
• For Resistance: R = E / I

Kirchhoff's Law:

• Kirchhoff's law, named after Mr. Gustav Robert Kirchhoff, these laws allowed to calculate the voltages and currents in multiple loop circuits.
• The amount of current that enters a junction is equivalent to the amount of current that leaves the junction.

                     Current into junction = Current leaving junction

• Kirchhoff's Current Law and Kirchhoff's Voltage Law are fundamental properties of circuits that make analysis possible.

Circuit Topology:

1. A Node: Any point where 2 or more circuit branches are connected together.
2. A Branch: Represents a single circuit (network) element; that is, any two nodes.
3. A Loop: loop is any closed path in a circuit (network). It is said to be independent  if it contains a branch which is not in any other loop.  

Law's:

1. Kirchhoff’s Current Law (KCL)

          - sum of all currents entering a node is zero

          - sum of currents entering node is equal to sum of currents leaving node

     

      2. Kirchhoff’s Voltage Law (KVL)

       

          - sum of voltages around any loop in a circuit is zero 

Kirchhoff's Rules:

1. Junction Rule: At any junction (3 or more connections) the sum of all currents = 0, there can be no charge work at the junction.
2. Loop Rule: The sum of the potential differences over all elements around a closed loop must = 0

Introduction To Resistors, Transistors and Capacitors

What is Resistors:

• A resistor is an electrical component that breaking points or directs the stream of electrical current in an electronic circuit. Resistors can likewise be utilized to give a particular voltage to a dynamic device, for example, a transistor.
• “It’s a component that resists the flow of current”.
• A resistor can be contrasted with a restriction in the stream of water through a hose - crimp the hose enough, and you can stop the stream. On the other hand, simply stick a washer with an opening in the hose, and confine the stream a settled sum. So a resistor restricts flow.

Resistors

Function of Resistor:

• Resistors assume an essential part to restrain the current and give just the required biasing to the vital active parts like the transistors and the ICs.
• To contradict the stream of current through resistor and the quality of this opposition is named as its resistance. German physicist, Sir G.S. Ohms could find an unequivocal relationship between voltage, current and resistance. As indicated by him a potential distinction or a voltage (V) over a resistor (R) is relative to the momentary current (I) coursing through it.

Types of Resistors:

1. Fixed and Variable Resistors
2. Carbon Film Resistors
3. Carbon Composition Resistors
4. Metal Film Resistors

What is Transistors:

• The invention of the transistor was made in the year 1948 that gave a remarkable shock to the electronics industry. 
• Transistors are a semiconductor device used to open up or switch electronic signs.
• A transistor is a device that controls current or voltage stream and goes about as a switch or gate for electronic signs. Transistors comprise of three layers of a semiconductor material, each equipped for conveying a current.

                 – an electrically controlled switch, or 

                 – a current amplifier.

Transistors

Advantages of Transistors:

1. Typically smaller size, lower expense and more life.
2. Can deal with small current.
3. Can be consolidated in the millions on one cheap die to make an incorporated circuit, though tubes are restricted to at most three utilitarian units for each glass bulb. 
4. Lower power utilization, less waste warmth, and high efficiency than equal tubes, particularly in small-signal circuits.
5. Can work on lower-voltage supplies for more safety, lower costs, more tightly clearances. 
6. Normally more physical toughness than tubes (relies on construction). 

Types of Transistors:

• Bipolar Junction Transistor (BJT)

               – NPN and PNP

• Junction Field Effect Transistor (JFET) 

              – N-channel and P-channel

• Metal Oxide Semiconductor FET (MOSFET)

              – Depletion type (n- and p-channel) and enhancement type (n- and p-channel)

What is Capacitors:

• Capacitors store energy in the electric field between a couple of conductors called plates. The storing of energy happens by "charging" the capacitor. Putting away happens when electric charges of equivalent magnitude, however inverse polarity, develop on every plate.
• The capacitor disengages current in direct present (DC) circuits and circuit in alternating current (AC) circuits. 
• A capacitor is somewhat similar to a battery, yet it has an alternate job to do. A battery utilizes chemicals to store electrical energy and discharge it gradually through a circuit; infrequently it can take quite a long while. A capacitor for the most part discharges its energy substantially more quickly—regularly in seconds or less.

Capacitors

General Uses of Capacitors:

1. Smoothing, particularly in power supply applications which required changing over the signal from AC to DC. 
2. Putting away Energy.
3. Signal decoupling and coupling as a capacitor coupling that blocks DC current and permit AC current to go in circuits.
4. Tuning, as in radio frameworks by associating them to LC oscillator and for tuning to the desired frequency.
5. Timing, because of the settled charging and releasing time of capacitors. 
6. For electrical force component correction and numerous more applications.

Types of Capacitors:

Capacitors are categorized in these different types:

• Electrolytic Type 
• Polyester Type
• Tantalum Type 
• Ceramic Type

Electronics Engineering Basic Concept

Semiconductors:

• Materials that grant flow of electrons are called conductors (e.g., gold, silver, copper, and so on.). 
• Materials that block flow of electrons are called insulators (e.g., elastic, glass, Teflon, mica, and so on.). 
• Materials whose conductivity falls between those of conductors and insulators are called semiconductors. 
• Semiconductors are "part-time" conductors whose conductivity can be controlled.

Semiconductors

Semiconductors Use:

Semiconductors are used as a part of numerous electrical circuits since we can control the flow of electrons in this material, for instance, with a controlling current. Semiconductors are also utilized for other unique properties.

How Semiconductor Works:

To see how semiconductors work, you should first comprehend somewhat about how electrons are sorted out in a molecule. The electrons in an atom are organized in layers. These layers are called shells. The peripheral shell is known as the valence shell.

Diodes:

• A Diode is the least complex two-terminal one-sided semiconductor device. It permits current to flow just in one direction and obstructs the current that flows the other way. The two terminals of the diode are called as anode and cathode.
• A Diode is an electronic device that permits current to flow in one direction only.
• Most diodes are made with semiconductor materials, for example, silicon, germanium, or selenium. 
• A few diodes are comprised of metal electrodes in a chamber emptied or loaded with a pure elemental gas at low pressure.

Diode

Characteristics of a Diode:

A perfect switch when open does not lead current in either directions and in closed state conducts       in both directions. 

The diodes is designed to meet these features hypothetically however are not accomplished for all       intents and purposes. So the practical diode qualities are just near that of the desired.

Diodes Uses:

Semiconductor diodes can be utilized for many applications. The fundamental application is clearly to correct waveforms. This can be utilized inside power supplies or inside radio detectors. Signal diodes can likewise be utilized for some different functions inside circuits where the "one way" impact of a diode might be required.

Types of Diodes:

An overview of the different types of diode that are available:

1. Backward Diode
2. Laser Diode
3. Light Emitting Diodes
4. PIN Diode
5. Stop recovery Diode
6. Tunnel Diode
7. Zener Diode
8. Photo Diodes