Experimental study on partial-combination method in continuous composite girder

<p>Cracking of concrete slab in the negative bending moment region of continuous composite girders is a key problem which needs to be solved in the design of continuous composite girder bridges. The main reason of concrete cracking in the negative bending moment region of continuous composite girder is tensile stress under the effects of temperature and load in the portion of integration. The paper gives the method of partial-combination to connect steel girder with concrete slab, that is, a rubber sleeve is placed on the stud of the negative bending moment region to increase the slip between the concrete slab and the steel girder at the joint. Two specimens of negative bending moment region are designed to observe the mechanical properties in the negative bending moment region of composite girders when using the method of partial-combination. The advantages and disadvantages of the partial-combination method are analysed.</p>

Determination of the kinematic coefficient of uneven rotation of the gear-belt transmission with a compound pulley

Known drive gears are analyzed. A gear-belt transmission with a composite roll pulley, including an elastic rubber sleeve, is proposed. Analytical expressions are obtained for determining the coefficient of kinematic non-uniformity of rotation of the driven pulley, its speeds and angular displacement as a result of deformation of the sleeve. Keywords gear-belt transmission, pulley, speed, coefficient of kinematic non-uniformity of rotation, moment, elastic modulus, stiffness, load. [email protected]

Static and Fatigue Behavior of Rubber-Sleeved Stud Shear Connectors as Part of Field-Cast Ultra-High Performance Concrete Connections

Field-cast ultra-high performance concrete (UHPC) connections are an innovative and prospective solution for combining full-depth precast concrete decks and steel girders. However, previous studies show that the slip capacity of stud shear connectors embedded in UHPC cannot meet the requirements for ductile connectors by Eurocode 4, which can reduce the resistance of steel and concrete composite members. In this study, the rubber-sleeved stud shear connector, which is a composite of ordinary stud and rubber sleeve, was adopted for the field-cast UHPC connections. Push-out tests were conducted to investigate the static and fatigue behavior of the rubber-sleeved stud shear connector as part of field-cast UHPC connections. Results of static tests showed that the rubber-sleeved stud shear connector has sufficient deformation capacity and its slip capacity is 1.5 times that of the ordinary stud shear connector. Compared to ordinary stud shear connectors, UHPC with high strength and stiffness has a relatively small effect on improving the shear strength and stiffness of rubber-sleeve stud shear connectors. Results of fatigue tests showed that the rubber-sleeved stud shear connector in UHPC has similar fatigue behavior to that in normal strength concrete. Though UHPC improves the restraint to the stud deformation, the influence of rubber sleeves is still decisive in determining the fatigue behavior of rubber-sleeve stud shear connectors. In addition, based on the results of strain gauges at stud roots, it was found that the crack initiation process consumes a small proportion of the fatigue life of rubber-sleeved stud shear connectors, which is about 5%.

Performance Evaluation of Spring for the Vehicle Suspension System Using the Nonlinear Finite Element Method

Air spring is used for the suspension system and it affects the vehicle stability and riding comfort by improving the impact-relief, braking, and cornering performance. Air Spring is comprised of the upper plate, lower plate, and rubber sleeve. Rubber sleeve is the composite material, which is made up of combination of rubber and Nylon, and the characteristics are changed according to the shape of rubber-sleeve, the angle of reinforcement cord. In this study, the distribution of internal stresses and the deformation of rubber composite material are analyzed through the nonlinear finite element method. The result showed that the internal maximum stresses and deformations about the changes of cord angle caused the more the Young's modulus decrease, the more maximum stress reduced.

Study on the Effect of Chassis Parameters on Light-Bus Steady State Handling Based on ADAMS

Aiming at the oversteer trend of a light-bus prototype in the steady state circular test with full load, a virtual prototype of the vehicle was constructed by using MSC.ADAMS/CAR. The modeling methods for the components such as leaf-spring, absorber and rubber sleeve, whose dynamic characteristics appear nonlinear, are discussed. The simulation results show the vehicle exhibits the oversteer behaviour which is consistent with the subjective sensation. To solve the problem, the chassis parameters affecting steady state handling are discussed. A version regulating the roll rate distribution of front and rear suspension was put forward. After some discussion, the sensitivity analysis of the front and rear stabilizer bar stiffness, leaf spring span, front and rear eyehook location of rear suspension are performed to improve steady state handling. Sensitivity analysis results show that decreasing the leaf spring span, increasing the diameter of front stabilizer bar, decreasing the diameter of rear stabilizer bar and moving front and rear eyehook location of rear suspension can solve oversteer problem. It is expected that the above conclusions can provide good technical solutions for engineering improvement.

Calcium Phosphate Hybridized with Human Semitendinosus and Gracilis Tendon Grafts

We hybridized calcium phosphate (CaP) with human semitendinosus and gracilis (ST/G) tendon grafts using an alternate soaking process. To evaluate quantitatively and histologically assess the CaP hybridized human ST/G tendon grafts, we classified them into three groups according to their soaking time – number of soaking cycle: 30 sec – 20 cycles (Group A), 1 min – 15 cycles (Group B), 3 min – 5 cycles (Group C). The tendon grafts were divided into three parts: tibial end (TE), femoral end (FE) and intra-articular (IA) portion. TE was secured using the Krackow technique with No. 2 nonabsorbable sutures, and an Endobutton-CL (Smith & Nephew, USA) was passed through the looped FE, as performed clinically. Then, the IA portion was covered with the sleeve of a rubber glove to prevent CaP hybridization. More soaking cycles induced greater deposition of CaP in the tendon grafts when the total soaking time was the same. Covering the IA portion with a rubber sleeve prevented of CaP deposition. A large amount of CaP in TE was deposited because suture holes increased the total contact area with the solutions.