The fracture threshold for an adhesive interlayer
Energy balance criterion for continuum mechanics analysis of fracture threshold for blistered adhesive elastic layer between elastic material and rigid substrate
Williams, M. L.↗
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Results for “continuum mechanics”
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Continuum theories for composite materials
Continuum mechanics application to elastic composite materials, investigating plane deformation of reinforced medium
Koh, S. L.↗
Crack propagation under variable load histories in linearly viscoelastic solids
Crack growth study in viscoelastic solids by linear continuum mechanics, discussing cyclic loads, composite solids mechanical behavior and thermodynamics
Dietmann, H.↗
On dispersion and characteristic motions of temperature rate dependent materials
Three dimensional theory of thermomechanical material developed using techniques of continuum mechanics and law of thermodynamics
Chang, T. S.↗
COMOC: Thermal analysis variant. User's manual
The Thermal Analysis Variant of the COMOC (computational continuum mechanics) computer system solves problems involving transient heat conduction and convection in stationary continua spanning arbitrarily irregular two-dimensional and axisymmetric solution domains. COMOC is based upon a finite element solution algorithm for the energy equation, and solves for the transient nodal temperature distribution using a highly stable and automatic explicit integration procedure. COMOC is extensively user-oriented, requires minimal input, and no a priori knowledge concerning the stability character of the differential equation system. It can readily output computed data in user-specified format fields, that geometrically resemble the solution domain discretization (for rapid engineering evaluation). Complete information is provided for applying COMOC to a specific problem.
Bauer, A. M.↗
Theory of rheology
The structure of the modern theory of rheology is discussed to show the assumptions and limitations. Rheology is discussed as a branch of continuum mechanics to determine the relationships between stress, strain, and strain rate which will give a closer representation of lubricant properties than the Newtonian flow equation. Rheology is also investigated as a branch of chemical physics. Consideration is limited to those theories of nonpolymeric and polymeric fluids which can represent viscoelasticity in terms of identifiable and measureable molecular characteristics. The possibility that elastic liquids may rupture in shear and linear tension analogous to the failure of solids is proposed.
Hutton, J. F.↗
Adhesive-bonded scarf and stepped-lap joints
Continuum mechanics solutions are derived for the static load-carrying capacity of scarf and stepped-lap adhesive-bonded joints. The analyses account for adhesive plasticity and adherend stiffness imbalance and thermal mismatch. The scarf joint solutions include a simple algebraic formula which serves as a close lower bound, within a small fraction of a per cent of the true answer for most practical geometries and materials. Digital computer programs were developed and, for the stepped-lap joints, the critical adherend and adhesive stresses are computed for each step. The scarf joint solutions exhibit grossly different behavior from that for double-lap joints for long overlaps inasmuch as that the potential bond shear strength continues to increase with indefinitely long overlaps on the scarf joints. The stepped-lap joint solutions exhibit some characteristics of both the scarf and double-lap joints. The stepped-lap computer program handles arbitrary (different) step lengths and thickness and the solutions obtained have clarified potentially weak design details and the remedies. The program has been used effectively to optimize the joint proportions.
Hart-Smith, L. J.↗
The motion of interconnected flexible bodies
The equations of motion for an arbitrarily interconnected collection of substructures are derived. The substructures are elastic bodies which may be idealized as finite element assemblies and are subject to small deformations relative to a nominal state. Interconnections between the elastic substructures permit large relative translations and rotations between substructures, governed by Pfaffian constraints describing the connections. Screw connections (permitting rotation about and translation along a single axis) eliminate constraint forces and incorporate modal coupling. The problem of flexible spacecraft simulation is discussed. Hurty's component mode approach is extended by permitting interconnected elastic substructures large motions relative to each other and relative to inertial space. The hybrid coordinate methods are generalized by permitting all substructures to be flexible (rather than only the terminal members of a topological tree of substructures). The basic relationships of continuum mechanics are developed.
Hopkins, A. S.↗
Free-vibration characteristics of a large split-blanket solar array in a 1-g field
Two methods for studying the free vibration characteristics of a large split blanket solar array in both a 0-g and a 1-g cantilevered configuration are presented. The 0-g configuration corresponds to an in-orbit configuration of the array; the 1-g configuration is a typical ground test configuration. The first method applies the equations of continuum mechanics to determine the mode shapes and frequencies of the array; the second method uses the Rayleigh-Ritz approach. In the Rayleigh-Ritz method the array displacements are represented by string modes and cantilevered beam modes. The results of this investigation are summarized by a series of graphs illustrating the effects of various array parameters on the mode shapes and frequencies of the system. The results of the two methods are also compared in tabular form.
Shaker, F. J.↗
Two-dimensional computer code for design assessment of SRM aft closure environment
A general interpolants method for constructing numerical analogs of the partial differential equations of continuum mechanics and which combines the best features of both finite element and finite difference methods was used in a two dimensional axisymmetric analysis of the space shuttle solid motor aft closure region flowfield. The numerical technique used is discussed as well as the results of the analysis. A steady state solution for the submerged nozzle nose region indicates the development of an area gas flow recirculation near the propellant burning surface boundary and in the region of the underside of the nozzle nose. This recirculation region remains spatially fixed for successive iterations (greater than 800) of the solution.
Freeman, J. A.↗
Computation of three-dimensional nozzle-exhaust flow fields with the GIM code
A methodology is introduced for constructing numerical analogs of the partial differential equations of continuum mechanics. A general formulation is provided which permits classical finite element and many of the finite difference methods to be derived directly. The approach, termed the General Interpolants Method (GIM), can combined the best features of finite element and finite difference methods. A quasi-variational procedure is used to formulate the element equations, to introduce boundary conditions into the method and to provide a natural assembly sequence. A derivation is given in terms of general interpolation functions from this procedure. Example computations for transonic and supersonic flows in two and three dimensions are given to illustrate the utility of GIM. A three-dimensional nozzle-exhaust flow field is solved including interaction with the freestream and a coupled treatment of the shear layer. Potential applications of the GIM code to a variety of computational fluid dynamics problems is then discussed in terms of existing capability or by extension of the methodology.
Spradley, L. W.↗
Computational strategy for the solution of large strain nonlinear problems using the Wilkins explicit finite-difference approach
The STEALTH code system, which solves large strain, nonlinear continuum mechanics problems, was rigorously structured in both overall design and programming standards. The design is based on the theoretical elements of analysis while the programming standards attempt to establish a parallelism between physical theory, programming structure, and documentation. These features have made it easy to maintain, modify, and transport the codes. It has also guaranteed users a high level of quality control and quality assurance.
Hofmann, R.↗
Impact melt generation and transport
The results from the first two calculations in a series of continuum mechanics computer code calculations, investigating the effects of variations in impactor mass and velocity on the generation and transport of impact melt, are reported. In the present calculations, the impactor is modeled as a spherical iron projectile with a mass of one trillion grams, and the target as a gabbroic anorthosite (GA) half-space, where the cases calculated have impact velocities of 5 and 15.8 km/sec. Early-time ejection velocities are 1-2 km/sec in both cases. The first calculation results in 0.07 projectile masses of GA being partly or completely melted, with all the melted GA being ejected from the crater, and a maximum impact range for the ejected melted material of 30 km. The second calculation yields 10.4 projectile masses of melted GA, 50% of which is ejected from the crater to ranges of up to about 130 km. Peak shock pressure attenuation with depth is reported for both cases, and transient cavity dynamics are described and compared to that for surface and near-surface explosions.
Orphal, D. L.↗
Multi-ring basin formation - Possible clues from impact cratering calculations
Finite difference continuum mechanics code calculations make it possible to vary the controlling variables in an impact event and to determine basic trends at scales unavailable to experimental analysis. Orphal et al. (1980) have summarized the results of a pair of such calculations for identical projectile/target characteristics but different impact velocities. One calculation considered a relatively low velocity iron impactor (5 km/s); the other, a high velocity iron impactor (15.8 km/s). The primary purpose was to investigate the generation and transport of impact melt for the two impact energies. Attention is given to crater growth, crater ejecta, and possible implications for basin-size events. Based on extrapolations, a new scenario is proposed. The scenario incorporates elements of several existing basin models.
Schultz, P. H.↗
Z-model analysis of impact cratering - An overview
The Maxwell Z-Model has been applied to two continuum mechanics computer calculations: (1) a laboratory-scale impact of an aluminum projectile into plasticene clay, and (2) a planetary-scale impact of an iron meteor into gabbroic anorthosite. The material flow in the cratering flow field may be well approximated by incompressible flow for most of the excavation stage of crater growth. The center of the flow field is located beneath, not at, the surface. Soon after energy partitioning is complete, Z can assume values less than 2.0 associated with the initial directedness of the projectile's momentum. The Z-Model parameters are time dependent during a significant portion of the crater growth time, and Z increases steadily with time from about 2.0 or slightly less at the beginning of the excavation stage to level off at values in the neighborhood of about 3.0 before the excavation stage is half-over.
Austin, M. G.↗
Constitutive Models Based on Compressible Plastic Flows
The need for describing materials under time or cycle dependent loading conditions has been emphasized in recent years by several investigators. In response to the need, various constitutive models describing the nonlinear behavior of materials under creep, fatigue, or other complex loading conditions were developed. The developed models for describing the fully dense (non-porous) materials were mostly based on uncoupled plasticity theory. The improved characterization of materials provides a better understanding of the structual response under complex loading conditions. The pesent studies demonstrate that the rate or time dependency of the response of a porous aggregate can be incorporated into the nonlinear constitutive behavior of a porous solid by appropriately modeling the incompressible matrix behavior. It is also sown that the yield function which wads determined by a continuum mechanics approach must be verified by appropriate experiments on void containing sintered materials in order to obtain meaningful numbers for the constants that appear in the yield function.
Rajendran, A. M.↗
Free-Edge Failures of Composite Laminates
The free-edge delamination of graphite/epoxy laminates under static loading is being analyzed to obtain fundamental understanding of the continuum mechanics involved. The analyses are conducted by idealizing the material response of each ply in the laminate as homogenous, linear elastic, and anisotropic. A generalized plane strain elastic boundary value problem was formulated to investigate the energy variation of such a body.
Source record↗
The effects of strain heating in lithospheric stretching models
The deformation by stretching of a continental type lithosphere has been formulated so that the problem can be solved by a continuum mechanical approach. The deformation, stress state, and temperature distribution are constrained to satisfy the physical laws of conservation of mass, energy, momentum, and an experimentally defined rheological response. The conservation of energy equation including a term of strain energy dissipation is given. The continental lithosphere is assumed to have the rheology of an isotropic, incompressible, nonlinear viscous, two layered solid.
Stanton, M.↗