Compressive Stress Strain

A test specimen under loading conditions located between the two flat, parallel faces of a testing machine is compressed at a specified rate (ASTM D 695). Stress and strain are computed from the measured compression test, and these are plotted as a compressive stress-strain curve for the material at the temperature and strain rate employed for the test. Procedures in compression testing are similar to those in tensile testing. However in compression testing particular care must be taken to...

Torsion Load

The next six typical concepts will allow motion through an elastomer in three or more directions. First, Fig. 2.16 would be a typical design for seismic concerns and bridge-bearing pads. It is capable of supporting high compressive loads while allowing for soft lateral (shear) and torsional characteristics. Although the part shown is a circular unit, square and rectangular products are more common in the construction industry. Fig. 2.17 shows another high shape factor design, which in this case...

Sphere

Circumferential load in the wall of all the spheres under internal pressure is equal to the pressure dmes the internal cross-sectional area, and the hoop stress, using the previous engineering assumption, is found to be It will readily be seen that no matter which section is chosen, provided the plane of the section passes through the center of the sphere, the condition will be the same, and it can be said that the hoop stress will be the same in all directions. it is determined that for wall...

Engineering data information source

In addition to what has been presented throughout this book such as the software on designing products in Chapter 5, this section provides source information concerning plastic material data basis. The available information worldwide has reached a volume that makes it impossible for one to review all the sources. In order to retrieve the desired or needed information, indexes and abstracts are continuously prepared by individual libraries, technical organizations, and professional societies. By...

Testing QC Statisticsnd People

Personnel or operators involved in testing from raw materials to fabricating products develop capability via proper training and experience. Experience and or developing the proper knowledge are required to determine the tests to be conducted. At times, with new problems developing on-line, different tests are required that may be available or have to be developed. Unfortunately a great deal of reinventing the wheel can easily occur so someone should have the responsibility to be up to date on...

High performance

As reviewed throughout this book the high performance materials are engineering plastics such as polycarbonate, nylon, acetal, and reinforced plastic (RP). Data on these plasties are provided throughout this book. In this section information on RPs is presented since they can provide a special form of high performance material that provides a designer with different innovative latitudes of performances than usually reviewed in textbooks. They are strong, usually inert materials bound into a...

Radome

Radome (radiation dome) is used to cover a microwave electronic communication antenna. It protects the antenna from the environment such as the ground, underwater, and in the air vehicles. To eliminate any transmission interference, it would be desirable not to use a radome since transmission loss of up to 5 occurs with the protective radome cover material. The radome is made to be as possibly transparent to electromagnetic radiation and structurally strong. Different materials can be used such...

Reinforced Plastics

The term reinforced plastic (RP) refers to composite combinations of plastic, matrix, and reinforcing materials, which predominantly come in chopped and continuous fiber forms as in woven and nonwoven fabrics. Other terms used to identify an RP include glass fiber reinforced plastic (GFRP), aramid fiber reinforced plastic (AFRP), boron fiber reinforced plastic (BFRP), carbon fiber reinforced plastic (CFRP), graphite fiber reinforced plastic (GFRP), etc. In addition to fabrics, reinforcements...

Marine Application

From ships to submarines to mining the sea floor worldwide, certain plastics and RPs can survive the sea environment. This environment can be considered more hostile than that on earth or in space. For water surface vehicles, many different plastics have been used in designs in successful products in both fresh and the more hostile seawater. Boats have been designed and fabricated since at least the 1940s. Anyone can now observe that practically all boats, at least up to 9 m (30 ft) are made...

Tank

Classical engineering stress analysis shows that hoop stress (stress trying to push out the ends of the tank) is twice that of longitudinal stress. To build a tank of conventional materials (steel, aluminum, etc.) requires the designer to use sufficient materials to resist the hoop stresses that results in unused strength in the longitudinal direction. In RP, however, the designer specifies a laminate that has twice as many fibers in the hoop direction as in the longitudinal direction. An...

Computer devices via DNA

DNA moves from biological to material to meet the speed of miniaturization. Ever had the creepy feeling that your computerized machine is taking on a life of its own, your coffeemaker is developing a personality, or your digital stereo is exhibiting its own taste in music That day may be much closer to reality when DNA is used to build electronic process control circuits. Yes, that's right, deoxyribonucleic acid, known as DNA and long held in awe as the wonder molecule of life, the software of...

Optimization

FEA is a major tool used to identify and solve design problems. Increased design efficiency provided by CAD has been augmented by the application of finite element methods to analysis, but engineers still often use a trial-and-error method for correcting the problems identified through FEA. This method inevitably increases the time and effort associated with design because it increases the time needed for interaction with the computer. Also, solution possibilities are often limited by the...

Product failure

The process of analyzing designs includes the modes of failure analysis reviewed in this book. At an early stage the designer should try to anticipate how and where a design is most likely to fail. The most common conditions of possible failure are elastic deflection, inelastic deformation, and fracture. During elastic deflection a part fails because the loads applied produce too large a deflection. In deformation, if it is too great it may cause other parts of an assembly to become misaligned...

Temperature

Temperature is the thermal state of matter as measured by a specific scale. Basically it is a measure of the intensity of the molecular energy in a substance. The higher temperatures have more molecular movement. The temperature at which molecular movement ceases completely is absolute zero it has been reached theoretically but not yet in actuality. Ambient temperature, usually synonymous with room temperature, denotes the surrounding environmental conditions such as pressure and temperature....

Electrical Electronic

The electrical and electronic industry continues to be not only one of the major areas for plastic applications, but a necessity in many applications worldwide with their many diversified electrical performance capabilities. They principally provide dielectric or insulation capabilities. The field can be a steady direct current (DC) field or an alternating current (AC) field and the frequency range may vary such as from 0 to 1010 Hz. The usual plastics are good insulators, however there are...

Poissons Ratio

Poisson's ratio is a required constant in engineering analysis for determining the stress and deflection properdes of materials (plasdcs, metals, etc.). It is a constant for determining the stress and deflection properties of structures such as beams, plates, shells, and rotating discs. With plastics when temperature changes, the magnitude of stresses and strains, and the direction of loading all have their effects on Poisson's rado. However, these factors usually do not alter the typical range...

Furniture

Plastic office furniture, principally just for chairs, panels, and laminates for desks, represents about a 10 billion market or just 3l 2 wt of all plastics. Unreinforced and glass reinforced PPs are principally used. Lawn and garden furniture consumes about 2xh wt plastics also principally using PPs. All these products as well as others have a good growth rate. An exercise follows in designing and fabricated furniture racks. Their function is to serve as a support that can hold several objects...

Abbreviations

Acetal (see POM) A ampere AA acrylic acid AAE American Assoc. of Engineers AAES American Assoc. of Engineering Societies AAR American Association of Railroads ABC acrylonitrile-butadiene-styrene ABR polyacrylate ABS acrylontrile-butadiene-styrene AC alternating current AC cellulose acetate ACES Accurate Clear Epoxy Solid ACS American Chemical Society ACTC Advanced Composite ADC allyl diglycol carbonate (also see CR-39) AEC Atomic Energy Commission AFCMA Aluminum Foil Container Manufacturer's...

Eulers Formula

The Euler's formula developed during 1759 by Leonard Euler (Swiss mathematician, 1707 to 1783) is used in product designs and also in designs using columns in molds and dies that processes plasdc. Euler's formula assumes that the failure of a column is due solely to the stresses induced by sidewise bending. This assumption is not true for short columns that fail mainly by direct compression, nor is it true for columns of medium length. The failure in such cases is by a combination of direct...

Database General Information

In addition to the databases and general information provided throughout this book (Chapter 6, etc.) other examples follow CAMPUS This internationally known database software Computer-Aided Material Selection uses uniform standards of testing methods comparing different plastics available from different material suppliers. It was developed by close cooperation with leading plastics producing companies. Special CAMPUS pages are on their websites, updated each time they finish further testing of...

RP Pipe

Figure 4.2 Loading 26 psi rigid concrete pipe left and flexible plastic pipe When compared to steel pipes there are similarities and dissimilarities. They both differ from concrete includes asbestos filled type pipe which is a rigid pipe that cannot tolerate bending or deflection to the same extent as RTR and steel pipe. The following review provides information on the design approach and results of tests conducted on these type pipes rigid RTR, rigid steel, and flexible concrete . They were...

Performance Behavior

All structures under load will deflect in some manner and the resultant moment will create bending and shear stresses. Therefore, it is important that the load analysis be executed correcdy. There are several major considerations that must be addressed before any mathematical analysis can be performed. The following conditions direcdy affect the design stresses that will be obtained by computations. Nylon, the resin base for the first series of STX composites, is a hygroscopic material....

Stress Whitening

It is the appearance of white regions in a TP when it is stressed. A stress-whitening zone may be a sign of crazing in some plastics where individual fine crazes may be difficult to detect. Stress whitening occurs fairly late in the rupture stage, just prior to yielding. The surface takes on a whitish appearance in regions that are under high stress. It is usually associated with yielding. For practical purposes, stress whiting is the result of the formation of microcracks or crazes that is a...

FALLO Approach

Conditions that are important in making plastic products the success it has worldwide are summarized in Fig. 1.15. Ail designs, processes, and materials fit into this overall FALLO Follow ALL Opportunities approach flow chart that produces products meeting required performance and cost requirements. Designers and processors, needing to produce qualified products at the lowest cost have used the basic concept of the FALLO approach. This approach makes one aware that many steps are involved to be...