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Time-dependent strength gain of a nonproprietary ultrahigh-performance concrete
Published in Hiroshi Yokota, Dan M. Frangopol, Bridge Maintenance, Safety, Management, Life-Cycle Sustainability and Innovations, 2021
M.P. Manning, T.S. Alahmari, B.D. Weldon
For the purpose of this investigation, the modulus of rupture strength was defined as the flexural stress corresponding to first-cracking and was evaluated by testing prismatic specimens in four-point bending based on ASTM C1609. Specimens were cast with a 76 mm wide by 102 mm deep cross-section and measured 406 mm in length. As shown in the test configuration in Figure 2, semi-circular end supports placed 51 mm from each end of the specimen created a 305 mm lower support span beneath a 102 mm upper load span. Force was applied using a 1780 kN capacity testing machine and measured by load cells centered below each support. Vertical deflection was measured by a string potentiometer attached to a removeable yoke at midspan. Two linear variable differential transformers (LVDTs) were fixed to the vertical face of the specimen, centered below one load point, and reaction supports were fixed directly below the opposite load point creating a 102 mm gauge length between the upper load span. The deformations induced by bending and measured by LVDTs were used to calculate beam curvature and identify the occurrence of first cracking.
Captain Cook Bridge Bearing Replacement
Published in Nigel Powers, Dan M. Frangopol, Riadh Al-Mahaidi, Colin Caprani, Maintenance, Safety, Risk, Management and Life-Cycle Performance of Bridges, 2018
W. Mengel, P. Adams, W. Hansford, J. Spathonis
The vertical movement of the jacks are controlled by a string potentiometer which produce 25 pulses per mm (Hansford 2011). Because the structure is heavily reinforced at the halving joint, it has a high transverse stiffness. Four independently controlled jacks could have been used however the loads in each jack would have varied widely because of the system tolerances. To overcome this, the hydraulic jacks were arranged in pairs. The load in each jack within a pair was identical. The computer system controlling the jacking operation was programed to control only two ‘1000t’ jacks with the area of each ‘1000t’ jack equal to twice the area of one 500t jack. The computer system automatically multiplies the programed jack area by the jacking pressure to display the jacking force of each jack pair.
Anthropomorphic Test Devices for Military Scenarios
Published in Melanie Franklyn, Peter Vee Sin Lee, Military Injury Biomechanics, 2017
A new linkage system was incorporated into the torso to allow multidirectional displacement measurement of the rib cage relative to the spine. This system, called the CRUX, consists of gimballed telescoping rods with a string potentiometer running down the centre that are attached to Ribs 3 and 6 on either side of the centreline. The string potentiometer indicates the overall length of the rods while the angles relative to the spine are measured by two rotary potentiometers. This system allows for the measurement of rib displacement at four locations on the anterior chest surface, which enables the dummy to better distinguish asymmetric loading from various combination of seatbelt and advanced airbag systems.
Abdominal biofidelity assessment of 5th percentile female ATD responses relative to recently developed belt and bar loading corridors
Published in Traffic Injury Prevention, 2023
Rakshit Ramachandra, Jason Stammen, Yun-Seok Kang, Erin Hutter, Laura Watkins, Kevin Moorhouse
Time zero for the tests was set when a relevant force measurement, which differed depending on the test condition, reached 50 N. Force applied to the abdomen in the belt pull tests was calculated as the sum of two tension seat belt load cell forces. In the rigid bar tests, the x-axis impact force (the force parallel to the line of motion of the impactor) was measured using a six-axis load cell installed between the ram shaft and the impactor face. The impact force data recorded were compensated to account for the mass in front of the load cell. Abdomen penetration (δAbd) was defined as the deflection of the abdomen versus time, where deflection is measured at the point anterior to the abdomen at the sagittal midline. In the belt loading tests, abdomen penetration was equal to belt penetration (δBelt) measured by an anterior string potentiometer (Eq. (1)). For the rigid bar tests, abdomen penetration was calculated by subtracting the displacement of the lumbar spine at the level of the impact from the displacement of the ram (δRam) measured via a linear potentiometer upon contact (Eq. (2)). Abdomen compression was calculated by dividing abdominal penetration by seated abdominal depth (225 mm for both HIII-05F and THOR-05F).
Increased foot-stretcher height improves rowing performance: evidence from biomechanical perspectives on water
Published in Sports Biomechanics, 2020
Yang Liu, Binghong Gao, Jiru Li, Zuchang Ma, Yining Sun
An instrumented single scull (Wudi, China) was used. Both gate force and angle in the horizontal plane were collected using specially designed gate sensor (Figure 3) that has a mechanical structure and measurement method very similar to the ROWX system (Webasport, Austria). These specially designed gate sensors completely replaced the original gate and allowed adjustment of gate height and blade pitch to ensure the same rigging set-up with the original gate, thus, eliminating the impact of rigging. Four strain gauges (1 KΩ, Beng Bu Zhong Chen Co. Ltd, AnHui Province, China) were glued to the pin and formed a Wheatstone bridge. Gate angles were collected via a servo potentiometer (5 KΩ, FCP12AC, 0.25% lineartiy, Sakae, Japan). The location of sliding seat was measured using a compact string potentiometer with voltage divider output (SP1-50, Celesco, USA). Boat velocity was measured using an impeller (Nielsen Kellermann) with embedded magnets, mounted underneath the hull of the boat. Boat acceleration in the direction of fore-aft direction was measured using an accelerometer (ADXL105, Analogue Devices, USA).
Detailed subject-specific FE rib modeling for fracture prediction
Published in Traffic Injury Prevention, 2019
Johan Iraeus, Linus Lundin, Simon Storm, Amanda Agnew, Yun-Seok Kang, Andrew Kemper, Devon Albert, Sven Holcombe, Bengt Pipkorn
Prior to testing, both rib ends were potted in 4 × 4 × 3 cm3 cups with Bondo® body filler (Bondo Corporation, Atlanta, GA, USA). Four strain gages were attached to the rib surface, two on the pleural surface and two on the cutaneous surface at 30% and 60% along the rib length axis measured from the posterior end (PSG1, PSG2, CSG1, and CSG2). Finally the rib potting material was attached to the potting brackets in the test apparatus, see Figure 1. A pendulum, with a mass of 54 kg and initial velocity 2 m/s, impacted the right side rod pushing the anterior (sternal) rib end to the left. The anterior displacement was recorded using a linear string potentiometer and the rotation of the anterior and posterior rib ends using rotational potentiometers. The posterior reaction forces were measured using a 6-axis load cell.