The present disclosure includes a method for determining a melt strength includes extruding one or more polymers to form the polymer film, passing the polymer film at least partially around a measurement roll coupled to a force measuring device, at least partially around a chill roll downstream of the measurement roll, and through a nip defined between two nip rolls, and measuring a force exerted on the measurement roll by the polymer film using the force measuring device. The polymer film is at least partially molten when contacting the measurement roll. A system includes an extruder, a measurement roll couple to one or more load cells, a chill roll coupled to a drive motor, at least two nip rolls downstream of the chill roll, and a take-up roll downstream of the nip rolls. The load cells measure a force exerted by the molten polymer film on the measurement roll.

Provided is a device for evaluating 360-degree bidirectional folding durability of a flexible material in which during a folding test of a film-type flexible material, a single folding device can implement both the infolding and outfolding of the flexible material relative to the unfolded state of the flexible material. To this end, the device includes: a fixing unit configured to fix a first side of the flexible material to be evaluated; a moving unit configured to fix a second side of the flexible material and disposed to be spaced apart from the fixing unit; a motion guide unit to which the fixing unit is fixed; and a motion unit connecting the motion guide unit with the moving unit.

Disclosed is a deepwater platform welded joint testing system. The testing system comprises a host unit, a hydraulic unit and a control unit, wherein the control unit is connected with the host unit and the hydraulic unit respectively; the host unit comprises a bearing frame placed on a bearing base, biaxial tension/compression loading oil cylinders mounted on the bearing frame, a lateral force resistant mechanism connected to the front ends of the biaxial tension/compression loading oil cylinders, counter-force supports fixed to the top end of the bearing frame and biaxial bending loading oil cylinders mounted on the counter-force supports. According to the deepwater platform welded joint testing system, through the independent or synergistic effect of the six loading oil cylinders, stretching and fatigue performance tests of a large complex structure under uniaxial tension/compression, uniaxial bending, biaxial tension/compression, biaxial bending and uniaxial/biaxial tension/compression and bending composite loads can be achieved.

A biaxial load test specimen includes a main body and four arms. The main body has a plurality of through-holes aligned along axial directions of two load axes orthogonal to each other. The four arms extend from the main body in the respective axial directions of the load axes. Each of the arms has a plurality of slit grooves extending, on respective extensions of the through-holes aligned in the axial directions, along the respective axial directions.

The present disclosure provides a system and method for testing dynamic properties of a material under a complex stress state, and belongs to the technical field of dynamic mechanical property tests. The system includes a control circuit system, a loading system, and a signal acquisition system. Based on the electromagnetic loading technology, the control circuit system controls charging and discharging of the loading system, the loading system loads the material, and the signal acquisition system acquires material strains and time characteristics during loading. The control circuit system can discharge 4 discharge coils simultaneously through the same discharging silicon-controlled rectifier (SCR), realizing biaxial bidirectional synchronous loading.

The expandable jacket and flexible ring comprises of the segmented circular arch shaped plates and bands or rings around the segmented plates. The test preparation consists of a membrane surrounding a specimen with or without a filter, segmented plates surrounding the membrane, and bands or rings around the segmented plates to permit uniform radial expansion of the specimen through its height when increments of vertical load are applied during the test, thereby providing accurate values of area of cross-section, deviator stress, volume change, modulus of elasticity, Poisson's ratio and shear strength. Using the flexible ring, three-dimensional consolidation tests are performed to determine three-dimensional coefficient of consolidation and coefficients of consolidation in horizontal and vertical directions. Removable attachments are used for assembling the expandable jacket and flexible ring during the test. A calibration device is used to determine the modulus of elasticity of the membrane and expandable jacket and flexible ring.

An apparatus for applying a force to a specimen is provided. The apparatus comprises: an output rotatable member comprising a plurality of connection points; a plurality of rigid connection means, each comprising a first end and a second end, wherein the first end of each connection

means is pivotably coupled to one of the plurality of connection points of the output rotatable member; a plurality of guide members; and a plurality of specimen holders, each slidably mounted to one of the guide members and pivotably coupled to the second end of one of the plurality of connection means.

A device and method for applying an internal pressure and resultant hoop stress to a hollow cylindrical object, such as a test cylinder, utilizing an expandable cylinder and upper and lower conically shaped rams. The device is inserted into a test cylinder, and when a compressive force is applied to the upper and lower conically shaped rams, the rams move vertically into upper and lower conically shaped cavities of the expandable cylinder. The sloped inner surfaces of the conically shaped upper and lower cavities convert the vertical motion into an outward radial motion, applying an internal pressure and resultant hoop stress to the cylindrical object.

Seat members 31 are held in a state of being movable with respect to first slide members 21 or second slide members 22 correspondingly. By rotating screws 39 in directions to increase the distances d between surfaces A of the first slide members 21 or the second slide members 22 and surfaces B of the seat members 31, chucks 25 are moved in directions to increase the distance between the chucks to apply pretension to a test piece correspondingly. When backlash in a force transmission system from a support part to the respective chucks 25 is eliminated, a biaxial tensile test is started.

The expandable jacket and flexible ring comprises of the segmented circular arch shaped plates and bands or rings around the segmented plates. The test preparation consists of a membrane surrounding a specimen with or without a filter, segmented plates surrounding the membrane, and bands or rings around the segmented plates to permit uniform radial expansion of the specimen through its height when increments of vertical load are applied during the test, thereby providing accurate values of area of cross-section, deviator stress, volume change, modulus of elasticity, Poisson's ratio and shear strength. Using the flexible ring, three-dimensional consolidation tests are performed to determine three-dimensional coefficient of consolidation and coefficients of consolidation in horizontal and vertical directions. Removable attachments are used for assembling the expandable jacket and flexible ring during the test. A calibration device is used to determine the modulus of elasticity of the membrane and expandable jacket and flexible ring.