Search Results for isothermal mechanical deflection system test

This article focuses on the isothermal fatigue of solder materials. It discusses the effect of strain range, frequency, hold time, temperature, and environment on isothermal fatigue life. The article provides information on various isothermal fatigue testing methods used to assess solder joint reliability. These include the accelerated thermal cycling test and isothermal mechanical deflection system test.

This article describes the phenomena of crack initiation and early growth. It examines specimen design and preparation as well as the apparatus used in crack initiation testing. The article provides descriptions of the various commercially available fatigue testing machines: axial fatigue testing machines and bending fatigue machines. Load cells, grips and alignment devices, extensometry and strain measuring devices, environmental chambers, graphic recorders, furnaces, and heating systems of ancillary equipment are discussed. The article presents technologies available to accomplish closed loop control of materials testing systems in performing standard materials tests and for the development of custom testing applications. It explores the advanced software tools for materials testing. The article includes a description of baseline isothermal fatigue testing, creep-fatigue interaction, and thermomechanical fatigue. The effects of various variables on fatigue resistance and guidelines for fatigue testing are also presented.

Electron beam hardening (EBH), with some special characteristics in comparison to other heat treatment technologies, allows beam deflection frequencies of up to 100 kHz. This article illustrates the principles of different thermal electron beam technologies, including beam-deflection, continuous EB interaction, EB flash, as well as multifield EB-deflection and multiprocess techniques. It characterizes the technical and technological possibilities for EBH in comparison to other surface-layer hardening processes. The article also discusses the technical design of electron beam facilities and the applications of EBH.

This article discusses the most common thermal analysis methods for thermosetting resins. These include differential scanning calorimetry, thermomechanical analysis, thermogravimetric analysis, and dynamic mechanical analysis. The article also discusses the characterization of uncured thermosetting resins as well as the curing process. Then, the techniques to characterize the physical properties of cured thermosets and composites are presented. Several examples of stress-strain curves are shown for thermosets and thermoplastic polymers.

This article briefly introduces some commonly used methods for mechanical testing. It describes the test methods and provides comparative data for the mechanical property tests. In addition, creep testing and dynamic mechanical analyses of viscoelastic plastics are also briefly described. The article discusses the processes involved in the short-term and long-term tensile testing of plastics. Information on the strength/modulus and deflection tests, impact toughness, hardness testing, and fatigue testing of plastics is also provided. The article describes tension testing of elastomers and fibers. It covers two basic methods to test the mechanical properties of fibers, namely the single-filament tension test and the tensile test of a yarn or a group of fibers.

This article reviews the general mechanical properties and test methods commonly used for ceramics and three categories of polymers, namely, fibers, plastics, and elastomers. The mechanical test methods for determining the tensile strength, yield strength, yield point, and elongation of plastics include the short-term tensile test, the compressive strength test, the flexural strength test, and the heat deflection temperature test. The most commonly used tests for impact performance of plastics are the Izod notched-beam test, the Charpy notched-beam test, and the dart penetration test. Two basic test methods for a group or strand of fibers are the single-filament tension and tow tensile tests. Room temperature strength tests, high-temperature strength tests, and proof tests are used for testing the properties of ceramics.

This article provides a review of fatigue test methodologies and an overview of general fatigue behavior, fatigue crack initiation and fatigue crack propagation of advanced engineering plastics. It also describes the factors affecting fatigue performance of polymers and concludes with information on fractography, a useful tool in failure analysis.

Characterization of nonmechanical properties is performed in the testing and certification of composite materials. This article focuses on the properties of composites that are commonly investigated. The properties include: per ply thickness; constituent content; density; coefficient of thermal expansion and coefficient of moisture expansion; glass transition temperature; thermal conductivity, diffusivity, and specific heat.

This article discusses stress relaxation testing on metallic materials, as covered by ASTM E 328. It reviews the two types of stress relaxation tests performed in tension, long-term and accelerated testing. The article illustrates load characteristics and data representation for stress relaxation testing used for the most convenient and common uniaxial tensile test. It concludes with information on compression testing, bend testing, torsion testing, and tests on springs.

Accelerated life testing and aging methodologies are increasingly being used to generate engineering data for determining material property degradation and service life (or fitness for purpose) of plastic materials for hostile service conditions. This article presents an overview of accelerated life testing and aging of unreinforced and fiber-reinforced plastic materials for assessing long-term material properties and life expectancy in hostile service environments. It considers various environmental factors, such as temperature, humidity, pressure, weathering, liquid chemicals (i.e., alkalis and acids), ionizing radiation, and biological degradation, along with the combined effects of mechanical stress, temperature, and moisture (including environmental stress corrosion). The article also includes information on the use of accelerated testing for predicting material property degradation and long-term performance.

This article discusses the thermal properties of engineering plastics and elastomers with respect to chemical composition, chain configuration, and base polymer conformation as determined by thermal analysis. It describes the processing of base polymers with or without additives and their response to chemical, physical, and mechanical stresses whether as an unfilled, shaped article or as a component of a composite structure. It summarizes the basic thermal properties of thermoplastics and thermosets, including thermal conductivity, temperature resistance, thermal expansion, specific heat, and glass transition temperature. It also provides information on polyimide and bismaleimide resin systems. Representative examples of different types of engineering thermoplastics are discussed primarily in terms of structure and thermal properties.

This article describes the fracture mechanics in fatigue. It discusses the fatigue crack growth rate (FCGR) testing that consists of several steps, beginning with selecting the specimen size, geometry, and crack length measurement technique. The two major aspects of FCGR test analysis are to ensure suitability of the test data and to calculate growth rates from the data. The article presents an analysis of the crack growth data. Optical, compliance, and electric potential difference are the most common laboratory techniques, and the article reviews their merits and limitations. Forced-displacement, forced-vibration, rotational-bending, resonance, and servomechanical systems for various loading conditions are also discussed.

Thermal analysis provides a powerful tool for researchers and engineers in determining both unknown and reproducible behavioral properties of polymer molecules. This article covers the thermal analysis and thermal properties of engineering plastics with respect to chemical composition, chain configuration, conformation of the base polymers, processing of the base polymers with or without additives; and the response to chemical, physical, and mechanical stresses of base polymers as unfilled, shaped articles or as components of composite structures. It also describes thermal analysis techniques, including differential scanning calorimetry, thermogravimetric analysis, thermomechanical analysis, and rheological analysis. This article also summarizes the basic thermal properties used in the application of engineering plastics, such as thermal conductivity, temperature resistance, thermal expansion, specific heat, and the determination of glass transition temperatures. It concludes with a discussion of the thermal and related properties of nine thermostat resin systems divided into three groups by low, medium, and high service temperature capabilities.

Testing and characterization of fatigue crack growth are used extensively to predict the rate at which subcritical cracks grow due to fatigue loading. ASTM standard E 647 is the accepted guideline for fatigue crack growth testing (FCGR) and is applicable to a wide variety of materials and growth rates. The two most widely used types of specimens are the middle-crack tension and compact-type specimens. This article describes the factors affecting the selection of appropriate geometries of these specimens: consideration of material availability and raw form, desired loading condition, and equipment limitations. Various crack measurement techniques, including optical, ultrasonic, acoustic emission, electrical, and compliance methods, are also reviewed. The article discusses the two major aspects of FCGR test analysis: to ensure suitability of the test data and to calculate growth rates from the data.

Several methods are developed for the numerical solution of partial differential equations, namely, meshed-solution methods such as the finite-element method (FEM), finite-difference method, and boundary-element method; and numerical algorithms consisting of so-called meshed-solution methods. This article introduces the methods of so-called meshed solutions, with an emphasis on the FEM. It presents some basic differential equations that are used to model the responses of structures, components, processes, or systems with emphasis on continuum mechanics. The article provides an outline on the mathematical principles of solving differential equations. It also reviews linear structural problems to illustrate the concept of the FEMs.

This article discusses the equipment design, procedures, experimental considerations, and interpretation of the torsion tests used to establish workability. It describes the application of torsion testing to obtain flow-stress data and to gage fracture-controlled workability and flow-localization-controlled failure. The article discusses the torsion test used to establish the processing parameters that are required to produce the desired microstructures.

This article addresses some established protocols for characterizing thermoplastics and whether they are homogeneous resins, alloyed, or blended compositions or highly modified thermoplastic composites. It begins with a discussion on characterizing mechanical, rheological, and thermal properties of polymer. This is followed by a section describing molecular weight determination using viscosity measurements. Next, the article discusses the use of cone and plate and parallel plate geometries in melt rheology. It then reviews the processes involved in the analysis of thermoplastic resins by chromatography. Finally, the article covers three operations of thermoanalysis, namely differential scanning calorimetry, thermogravimetric analysis, and thermomechanical testing.