Static loads are constant mechanical forces that do not change over time, such as the weight of a building or a parked car. Dynamic loads vary in direction, position and magnitude, such as people, traffic, earthquakes and wind. Strain rate refers to the rate at which a material deforms under stress over time. Durability is the ability of a material to last a long time without deterioration. Fatigue is structural damage caused by cyclic loading, and is a major cause of engineering failures. Failure modes and the design approach are also discussed.

1. Static Load
 Static load, which is constant and steady and produces a single
response.
 A static load is a mechanical force applied slowly to an assembly
do not change over time but remain constant.
 Examples of static loads include the weight of a building bearing
a car parked on a road.
 Static loads are also known as dead loads or holding loads.
 A static load in a structure refers to any load, whether the weight
another stationary load, that exerts itself on the structure. For
on top of a building is a static load.
 They are used to work out the maximum load for a range of
well as for determining the ultimate tensile strength of materials.

2. Dynamic Load
 Dynamic load is one that changes in direction, position and magnitude,
creating varied forces on a structure.
 These types of loads exert forces onto a structure that are often much
equivalents.
 Types of dynamic load include people, traffic, earthquakes, wind,
structure can be subjected to dynamic loading and the changes that
can be random, periodic or a combination of the two.
 Example, someone jumping up and down will exert a greater force on
standing still.
 Dynamic loads tend to have a greater impact on a structure than static
of force. Force = mass x acceleration
 As the mass accelerates, so the force increases and the same goes for

3. Strain Rate
 Strain rate is the rate of deformation caused by strain in material within
a corresponding time.
 Thestrain ratecan be determined by the formula:
Strain Rate= Changein Strain /Changein Time
 Strain rate involves the rate wherein a material shrinks orexpands and the rateof deformation broughtby
progressive shearing without a change involume.
Durability
 Durability is the ability to last a long time without significant deterioration
 A durable material helps the environment by conserving resources and
reducing wastes and the environmental impacts of repair and replacement.

4. Fatigue
 Fatigue is the progressive and localized structural damage that
occurs when a material is subjected to cyclic loading.
 Themajority of engineeringfailuresare caused by fatigue. Thetype of fatigue of most concernincircuit boards,
gasoline, diesel, gas turbineenginesand manyindustrial applications is thermal fatigue
Fatigue failure occurs in three stages
•Crackinitiation
•Slow, stable crackgrowth
•Rapid fracture

5. Failure Modes

6. Design Approach
The engineering design process is a series of steps that engineers follow to
find a solution to a problem. The steps include problem-solving processes
such as, for example, determining your objectives and constraints,
prototyping, testing and evaluation.