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 provides practical information and data on property development in engineering plastics. It discusses the effects of composition on submolecular and higher-order structure and the influence of plasticizers, additives, and blowing agents. It examines stress-strain curves corresponding to soft-and-weak, soft-and-tough, hard-and-brittle, and hard-and-tough plastics and temperature-modulus plots representative of polymers with different degrees of crystallinity, cross-linking, and polarity. It explains how viscosity varies with shear rate in polymer melts and how processes align with various regions of the viscosity curve. It discusses the concept of shear sensitivity, the nature of viscoelastic properties, and the electrical, chemical, and optical properties of different plastics. It also reviews plastic processing operations, including extrusion, injection molding, and thermoforming, and addresses related considerations such as melt viscosity and melt strength, crystallization, orientation, die swell, melt fracture, shrinkage, molded-in stress, and polymer degradation.

The discussion on the fracture of solid materials, both metals and polymers, customarily begins with a presentation of the stress-strain behavior and of how various conditions such as temperature and strain-rate affect the mechanisms of deformation and fracture. This article describes crazing and fracture in polymeric materials, with a review of the behavior of the elastic modulus as a function of temperature or time parameters, emphasizing the importance of the viscoelastic nature of their deformation and fracture. The discussion covers the behavior of polymers under stress, provides information on ductile and brittle behaviors, and describes craze initiation in polymers and crack formation and fracture by crazing. Macroscopic permanent deformation of polymeric materials caused by shear-yielding and crazing, which eventually can result in fracture and failure, is also covered.

There are many reasons why plastic materials should not be considered for an application. It is the responsibility of the design/materials engineer to recognize when the expected demands are outside of what the plastic can provide during the expected life-time of the product. This article reviews the numerous considerations that are equally important to help ensure that part failure does not occur. It provides a quick review of thermoplastic and thermoset plastics. The article focuses primarily on thermoset materials that at room temperature are below their glass transition temperature. It describes the motivation for material selection and the goal of the material selection process. The use of material datasheets for material selection as well as the processes involved in plastic material selection and post material selection is also covered.

Understanding the mechanical properties of aluminum alloys is useful for the designer for choosing the best alloy and establishing appropriate allowable stress values, and for the aluminum producer to control the fabrication processes. This article discusses the nature and significance of mechanical property data and of stress-strain curves detailing the effects of mechanical properties on the design and selection of aluminum alloys. The properties include tensile, compressive, shear, bearing, creep and creep-rupture, fatigue, and fracture resistance properties.

Understanding the mechanical properties of aluminum alloys is useful for the designer for choosing the best alloy and establishing appropriate allowable stress values, and for the aluminum producer to control the fabrication processes. This article discusses the nature and significance of mechanical property data and of stress-strain curves detailing the effects of mechanical properties on the design and selection of aluminum alloys. The properties include tensile, compressive, shear, bearing, creep and creep-rupture, fatigue, and fracture resistance properties.

This article describes a method to predict mechanical properties of cast iron materials and illustrates how to use the predictions in computer-aided tools for the analysis of castings subjected to load. It outlines some ways to predict the hardness and elastic modulus of cast iron without going into dislocation theory. The article discusses modeling of hardness in cast iron based on a regular solution equation in which the properties of each phase depend on chemical composition and coarseness. It describes the evaluation of material parameters from the tensile stress-strain curve. The article concludes with an illustration of a finite-element method (FEM) model containing heterogeneous mechanical properties using local material definitions.

This article focuses on the analyzing and modeling of stress-strain behavior of polycrystals of pure face-centered cubic (fcc) metals in the range of temperatures and strain rates where diffusion is not important. It presents a phenomenological description of stress-strain behavior and provides information on the physical background, alternative interpretations, and directions of research. The quantitative description of strain hardening of fcc polycrystals is provided. The article also discusses the modeling of stress-strain behavior in body-centered cubic metals, hexagonal metals, stage IV work hardening, and the various classes of single-phase alloys.

This article describes different types of titanium alloys, including alloy Ti-6Al-4V, alpha and near-alpha alloys, and alpha-beta alloys. It explains the formability of titanium alloys with an emphasis on the Bauschinger effect. The article provides information on the tool materials and lubricants used in the forming process. It provides information on the cold and hot forming, superplastic forming, and combination of superplastic forming/diffusion bonding. The article discusses the various forming processes of these titanium alloys, including press-brake forming, power (shear) spinning, rubber-pad forming, stretch forming, contour roll forming, creep forming, vacuum forming, drop hammer forming, joggling, and explosive forming.

Many shearing, blanking, and piercing operations are based on the same underlying principles of shear mechanisms. This article provides information on the various operations associated with die cutting and describes three phases involved in the shear cutting or punching action. These phases include deformation, penetration and fracture. The article also explains the effect of clearance on tool life and force and power requirements. It reviews the forces involved in the punching process and describes the diameter of a hole or blank in relation to material thickness. The limitations of punching are also discussed. The article describes the relationship of the die clearance to stress-strain curves and explains the procedure of interpreting the stress-strain curves. The article concludes with information on the dynamic stripping forces in blanking.

This article provides the definitions of stress and strain, and describes the relationship between stress and strain by stress-strain curves and true-stress/true-strain curves. The emphasis is on understanding the factors that determine the extent of deformation a metal can withstand before cracking or fracture occurs. The article reviews the process variables that influence the degree of workability and summarizes the mathematical relationships that describe the occurrence of room-temperature ductile fracture under workability conditions. It discusses the most common situations encountered in multiaxial stress states. The construction of a processing map based on deformation mechanisms is also discussed.

Microstructure and crystallographic texture are the key material features used in the continuous endeavor to relate the processing of a metal with its final properties. This article emphasizes several aspects of deformation microstructures, namely, microstructural evolution, dislocation boundaries, and macroscopic properties. It discusses three different microstructural types: cell blocks, TL blocks, and equiaxed subgrains. The article also emphasizes the behavior of metals and single-phase alloys processed under plastic deformation (dislocation slip) conditions. It provides information on the microstructural parameters, measurement techniques, and microstructural relationships, which assist in predicting the mechanical properties and recrystallization behavior of materials. The article concludes with an analysis of the general relationship between the microstructural parameters and properties.

This article provides a description of the microscale models and mechanisms for deformation and fracture. Macroscale and microscale appearances of ductile and brittle fracture are discussed for various specimen geometries and loading conditions. The article reviews the general geometric factors and materials aspects that influence the stress-strain behavior and fracture of ductile metals. It highlights fractures arising from manufacturing imperfections and stress raisers. The article presents a root cause failure analysis case history to illustrate some of the fractography concepts.

The properties of unidirectional composite (UDC) materials are quite different from those of conventional, metallic materials. This article provides information on the treatment of UDC stress-strain relations in the forms appropriate for analysis of thin plies of material. It explains the development of the relations between mid-surface strains and curvatures and membrane stress and moment resultants. The article discusses the properties, such as thermal expansion, moisture expansion, and conductivity, of symmetric laminates and unsymmetric laminates. It describes the distribution of temperature and moisture through the thickness of a laminate. Stresses caused due to mechanical loads, temperature, and moisture on the laminate are analyzed. The article concludes with information on interlaminar cracking, free-edge delamination, and transverse cracks of laminates.

A characteristic feature of bending is the inhomogeneous (nonuniform) nature of the deformation. Therefore, in a bent specimen, the strain and stress at a given point are dependent on the location of the point with respect to the neutral axis of the cross-sectional area of the specimen. This article discusses the stress-strain relationships, strain curvature, and stress-moment equations for elastic, noncylindrical, elastic-plastic, and pure plastic bending conditions. It also reviews the distribution of residual stress and springback.

The separation of the fatigue process into crack initiation and propagation phases has been an important and useful advance in engineering. The combined approach of strain-control testing and the development fracture mechanics of fatigue crack growth rates is a key advance that allows better understanding and simulation of both crack nucleation and the subsequent crack growth mechanisms. This article reviews three basic types of fatigue properties: stress-life, strain life, and fracture mechanic crack growth.

THE TENSION TEST is one of the most commonly used tests for evaluating materials. The material characteristics obtained from tension tests are used for quality control in production, for ranking performance of structural materials, for evaluation of alloys, and for dealing with the static-strength requirements of design. This article describes the stress-strain behavior during a tension test and provides the definition of terms such as stress, force, strain, and elongation. It explains the tensile properties obtained from the test results: the tensile strength and yield strength, which includes offset yield strength, extension-under-load yield strength, and upper yield strength. The article concludes with a description of the general procedures for conducting the tension test based on ASTM standards and the variability of tensile properties.

Compression tests are used for subscale testing and characterizing the mechanical behavior of anisotropic materials. This article discusses the characteristics of deformation during axial compression testing, including deformation modes, compressive properties, and compression-test deformation mechanics. It describes the procedures for the use of compression testing for the measurement of the deformation and fracture properties of materials. The article provides a detailed discussion on the technique involved in determining the stress-strain behavior of metallic materials based on the ASTM E 9, "Compression Testing of Metallic Materials at Room Temperature." It also reviews the factors that influence the generation of test data for tests conducted in accordance with the ASTM E 9 and the capabilities of conventional universal testing machines for compression testing.

Split-Hopkinson pressure bar (SHPB) testing is traditionally used for determining the plastic properties of metals (which are softer than the pressure bar material) at high strain rates. However, the use of this method for testing ceramic has various limitations. This article provides a discussion on the operational principle of the traditional SHPB technique and the relevant assumptions in the derivation of the stress-strain relationship. It describes the inherent limitations on the validity of these assumptions in testing ceramics and discusses the necessary modifications in SHPB design and test procedure for evaluating high-strength brittle ceramics. The article includes information on the maximum strain rate that can be obtained in ceramics using an SHPB and the necessity of incident pulse shaping. It also reviews the specimen design considerations, interpretation of experimental results obtained from SHPB testing of ceramics, and effectiveness of the proposed modifications.

Forming processes can be divided into three major categories: bulk forming, sheet-metal forming, and semisolid forming and polymer extrusion. This article introduces each process category with a description of the constitutive models. It outlines the required properties for process modeling and describes the test methods for determining these properties. The article discusses several compression tests used to determine stress-strain curves for bulk forming and tensile tests used to obtain stress-strain curves for sheet-metal forming. The article concludes with information on the measurement of viscosity of semisolid alloy materials by using three types of viscometers: the coaxial cylinder viscometer, the cone-and-plate viscometer, and the capillary viscometer.