No abstract available

[en] The possibilities for the computation of elasticplastic properties via dynamic relaxation are shown. From the various theories of plasticity the laws of Prandtl-Reuzs for solidifying materials were chosen for in this investigation. The calculation is carried out directly without further linearizations in a single computer run. It is possible to obtain an approximate solution via a direct process involving a fictitious elastic material law. Two disks with - according to the theory of elasticity - single stress points are used as examples. (orig.)

No abstract available

[en] This course is an introduction to rheology, that is to say the laws of materials behavior. It includes three parts, the first part is concerned with the general laws of materials behavior, the other two being on the study of two important types of behavior: viscoelasticity, and plasticity

No abstract available

No abstract available

[en] A theoretical framework is given for designing possibly cracked structures to remain ductile under accidental overloads. For non-hardening, fully-plastic plane strain crack growth in a number of geometries and loadings, near tip fields are characterized by three parameters: the slip line angle θ_s and the normal stress σ_s and shear displacement δu_s across the slip line. These parameters are found in terms of the far-field geometries and loadings through slip line fields or at least upper bound analyses based on circular arcs. Then the crack growth criterion in terms of the crack tip opening angle (CTOA) is proposed as a function of near tip parameters and material properties. Experiments are suggested to determine the dependence of the CTOA on those variables

[en] Recently, environmental embrittlement has been investigated in many ordered intermetallics including Co₃Ti, Ni₃Al, Ni₃Si, FeAl, Fe₃Al, and (Fe,Co)₃V. At ambient temperatures, the embrittlement is caused mainly by hydrogen released from moisture in air. A number of intermetallics also show a reduction in ductility at elevated temperatures; however, the cause of the ductility reduction is not well understood at the present time. Oxygen is identified as an embrittling agent in Ni₃Al and Ni₃Si alloys but apparently not in other alloys such as Ni₃[Si,Ti] and Co₃Ti. L1₂-ordered intermetallic alloys with compositions (Fe₂₂Co₇₈)₃V exhibited moisture-induced hydrogen embrittlement when tested in air at ambient temperatures. Their ductility also decreases with increasing temperature above 500 C and reaches a minimum around the critical ordering temperature [T_c = 910 C] when tested in vacuum. At present, there is no detailed study of the environmental effect in (Fe,Co)₃V at elevated temperatures. In this study, the environmental effect on the ductility and fracture in (Fe,Co)₃V is investigated at various temperatures and in various atmospheres, and the results are compared with those from other intermetallic alloys

[en] This paper discusses an alloy provided which has good operating strength and ductility at temperatures of 2000 degrees to 2500 degrees F. and density of between 6.5 and 7.0 g/cm³. The alloy contains niobium titanium hafnium and aluminum

[en] A numerical model for the analysis of hollow beam impact have been developed. The moment-rotation relationship of a plastic hinge is used in a nonlinear, implicit code for transient analysis. The moment-rotation curve is obtained from a basic skeleton curve, by adding a second one with irreversible characteristics. Both models may be selected from a variety of functions. A hysteric model may also be chosen, as the code allows to deal with a wide range of structural problems. (author). 4 refs., 3 figs