Filetype
Recent experimental studies suggest that the nociceptive withdrawal reflex system essentially has a "modular" organization, with each module concerned with the control of a single or a small group of muscles. This organizational principle appears to apply also to some spinoolivocerebellar pathways.
It is now well documented that the cerebellar cortex is divided into sagittal zones which can be identified by their climbing fibre inputs from specific regions of the inferior olive. Each cortical zone sends its efferent fibres, the Purkinje cell axons, to a separate group of neurones in the cerebellar or vestibular nuclei (Oscarsson, 1980, Voogd and Bigare, 1980, Voogd, 1982, Trott and Armstrong
Denna forskningsrapport sammanfattar resultaten från en studie bedriven inom ramen för Pilotverksamheten för bedömning av reell kompetens (REKO) under ledning av Universitets- och Högskolerådet (UHR). I studien utvecklas:• en generisk valideringsmodell för bedömning av reell kompetens för tillgodoräknande som högskoleutbildning. Valideringsmodellen (av både summativ och formativ karaktär) ska kunn
Summary and conclusions. On the spinal and supraspinal outputs from the superficial dorsal horn.
The fracture toughness of a polymer-metal laminate composite is obtained by mechanical testing of a specimen containing a pre-crack. The laminate is a material used for packaging. It consists of a thin aluminium foil and a polymer coating. A centre cracked panel test geometry is used. Each of the layers forming the laminate is also tested separately. The result is compared with the measured fractuThe fracture toughness of a polymer-metal laminate composite is obtained by mechanical testing of a specimen containing a pre-crack. The laminate is a material used for packaging. It consists of a thin aluminium foil and a polymer coating. A centre cracked panel test geometry is used. Each of the layers forming the laminate is also tested separately. The result is compared with the measured fractu
Stress intensity factors are calculated for long plane cracks with one tip interacting with a region of graded material characteristics. The material outside the region is considered to be homogeneous. The analysis is based on assumed small differences in stiffness in the entire body. The linear extent of the body is assumed to be large compared with that of the graded region. The crack tip, incluStress intensity factors are calculated for long plane cracks with one tip interacting with a region of graded material characteristics. The material outside the region is considered to be homogeneous. The analysis is based on assumed small differences in stiffness in the entire body. The linear extent of the body is assumed to be large compared with that of the graded region. The crack tip, inclu
Bi-materials composed of thin layers ideally bonded to large substrates are considered. Cracksemerging from an almost flat surface and propagating through the bi-materials are studied.The cracks acquire realistic geometrical shapes, where the tips are integral parts of the cracksurfaces. Crack propagation is related to surface evolution resulting from material loss due tocorrosion. Controlling mecBi-materials composed of thin layers ideally bonded to large substrates are considered. Cracks emerging from an almost flat surface and propagating through the bi-materials are studied. The cracks acquire realistic geometrical shapes, where the tips are integral parts of the crack surfaces. Crack propagation is related to surface evolution resulting from material loss due to corrosion. Controlling
Fracture behavior of an ultra thin aluminium foil was studied. For very short crack lengths, fracture has been followed in the scanning electron microscope (SEM) with a tensile stage. A single edge notched tension specimen was used. Crack length and applied load during the crack growth were measured. These results have been used to calculate fracture strength using linear elastic fracture mechanicFracture behavior of an ultra thin Aluminium foil was studied. For very short crack lengths, fracture has been followed in the scanner electronic microscope (SEM) with a tensile stage. A single edge notched tension specimen was used. Crack length and applied load during the crack growth were measured. These results have been used to calculate fracture strength using linear elastic fracture mechani
This work proposes a model for corrosion driven crack growth. The model poses a moving boundary problem, where a chemical attack removes material from the body. The rate of the chemical attack is a function of the strain along the body surface. No crack growth criterion is needed for the analysis. A finite strain formulation is used and the material model is assumed hyperelastic. The problem is st
A study of crack propagation paths in the situation where the crack is suppressed to open during growth due to high compressive forces has been performed. This problem was analyzed theoretically very recently by the authors and is here extended to involve a limited number of illustrative experimental results reported elsewhere in the literature. By analyzing the experimental crack growth patterns,A study of crack propagation paths in the situation where the crack is suppressed to open during growth due to high compressive forces has been performed. This problem was analyzed theoretically very recently by the authors and is here extended to involve a limited number of illustrative experimental results reported elsewhere in the literature. By analyzing the experimental crack growth patterns,
A directional crack growth prediction in a compressed homogenous elastic isotropic material under plane strain conditions is considered. The conditions at the parent crack tip are evaluated for a straight stationary crack. Remote load is a combined biaxial compressive normal stress and pure shear. Crack surfaces are assumed to be frictionless and to remain closed during the kink formation whereforA directional crack growth prediction in a compressed homogenous elastic isotropic material under plane strain conditions is considered. The conditions at the parent crack tip are evaluated for a straight stationary crack. Remote load is a combined biaxial compressive normal stress and pure shear. Crack surfaces are assumed to be frictionless and to remain closed during the kink formation wherefor
Directional crack growth criteria in compressed elastic-plastic materials are considered. The conditions at the crack tip are evaluated for a straight stationary crack. Remote load is a combined hydrostatic stress and pure shear, applied via a boundary layer assuming small scale yielding. Strains and deformations are assumed to be small. Different candidates for crack path criteria are examined. MDirectional crack growth criteria in compressed elastic–plastic materials are considered. The conditions at the crack tip are evaluated for a straight stationary crack. Remote load is a combined hydrostatic stress and pure shear, applied via a boundary layer assuming small scale yielding. Strains and deformations are assumed to be small. Different candidates for crack path criteria are examined. M
The behaviour of the stress intensity factor is investigated for a long plane crack with one tip interacting with a strip of graded elastic properties. The material outside the strip is postulated to be homogeneous linear elastic and the material in the graded region is assumed to have continuous change of modulus of elasticity. Changes of the Poisson’s ratio are ignored. The body is assumed to be
A special choice of two functions is proposed for analysing non-homogeneous materials, when both modulus of elasticity and Poisson’s ratio experience spatial variations. It is shown that in the case of abrupt change of the two basic material’s characteristics, these two functions degenerate to constants, which are linear combinations of Dundurs’ parameters. The properties of the two functions are
Crack growth across an interface between materials with different strength is examined by a cohesive zone model. The two materials have identical elastic properties but different fracture process properties, or different yield stresses, which is modeled by different cohesive stresses. The fracture criteria is a critical crack opening displacement. Load is represented by a stress intensity factor d
