Quantification of Head Acceleration Events in Rugby League: An Instrumented Mouthguard and Video Analysis Pilot Study

Instrumented mouthguards (iMG) were used to collect head acceleration events (HAE) in men’s professional rugby league matches. Peak linear acceleration (PLA), peak angular acceleration (PAA) and peak change in angular velocity (ΔPAV) were collected using custom-fit iMG set with a 5 g single iMG-axis recording threshold. iMG were fitted to ten male Super League players for thirty-one player matches. Video analysis was conducted on HAE to identify the contact event; impacted player; tackle stage and head loading type. A total of 1622 video-verified HAE were recorded. Approximately three-quarters of HAE (75.7%) occurred below 10 g. Most (98.2%) HAE occurred during tackles (59.3% to tackler; 40.7% to ball carrier) and the initial collision stage of the tackle (43.9%). The initial collision stage resulted in significantly greater PAA and ΔPAV than secondary contact and play the ball tackle stages (p < 0.001). Indirect HAE accounted for 29.8% of HAE and resulted in significantly greater ΔPAV (p < 0.001) than direct HAE, but significantly lower PLA (p < 0.001). Almost all HAE were sustained in the tackle, with the majority occurring during the initial collision stage, making it an area of focus for the development of player protection strategies for both ball carriers and tacklers. League-wide and community-level implementation of iMG could enable a greater understanding of head acceleration exposure between playing positions, cohorts, and levels of play.

Reinforced Concrete Circular T-Shaped Deep Beams – Finite Element Investigation

The current work investigates the behavior and strength of T-shaped cross section ring deep beams through a Finite element parametric study. Currently, ring diameter, loading type, concrete compressive strength and number of supports are taken into consideration. It is found that increasing ring diameter of beam by 12.5-25% leads to increase the maximum positive moment, maximum negative moment, maximum torsional moment and midspan deflection by 1.1-2.2%, 2.2-4.3%, 3-6% and 16-33%, respectively, while the load ultimate capacity increases by 11-17%. The positive and torsional moments at midspan and midspan deflection decrease by 23-36%, 3-11% and 6-14%, respectively when the loading type varies from concentered to full uniformly load over a span length of 33, 50, 67 and 100%, respectively. In a related context, this change in load type leads the negative moment at support and the load ultimate capacity to increase by 2-21% and 6-85%, respectively. The midspan positive moment, negative moment, torsional moment and load ultimate capacity increase by 20.4-71.3%, 20-69.7%, 15.6-43.8% and 21-73%, respectively, whereas deflection decreases by 1.4-11%, when increasing the compressive concrete strength by 45-190%. Finally, it is found that the load ultimate capacity increases by 82-348%, when number of supports increases by 25-100%, while torsional moment, maximum positive moments, maximum negative moments and midspan deflection decrease by 11-50%, 38-76.4%, 38.6-76.8% and 14-39%, respectively due to this increase in the number of supports.

Dynamic Modeling of a Front-Loading Type Washing Machine and Model Reliability Investigation

A linear dynamic model of a front-loading type washing machine was developed in this study. The machine was conceptualized with three moving rigid bodies, revolute joints, springs, and dampers along with prescribed rotational drum motion. Kane’s method was employed for deriving the equations of motion of the idealized washing machine. Since the modal and transient characteristics can be conveniently investigated with a linear dynamic model, the linear model can be effectively used for the design of an FL type washing machine. Despite the convenience, however, the reliability of the linear dynamic model is often restricted to a certain range of system parameters. Parameters relevant to the reliability of the linear dynamic model were identified and the parameters’ ranges that could guarantee the reliability of the proposed linear dynamic model were numerically investigated in this study.

Structural Resistance of Simplified Side Hull Models Accounting for Stiffener Design and Loading Type

Thin-walled stiffened panels are fundamental structural components that form the primary structure of the ship hull. The effectiveness of the stiffener configuration design needs to be assessed because members are unavoidably subjected to various load types during operations. In this situation, assessment is required to quantify the responses and determine the relationship between the structural resistance and input parameters. The aim of this work was to obtain structural resistance data on the stiffened side hull of a medium-sized tanker with various model configurations by using finite element analysis with different loading parameters, i.e., load type and angle, as the main inputs. The results indicate that stiffener configurations subjected to loads at the center and random positions influence the effectiveness in reducing the deformation. The results show that the stiffener is more effective when the location of the force is very close to the stiffener. Therefore, higher strength can be obtained with a design in which the area that is not supported by the stiffener is minimized.

Modeling the Repair of a Crack in an HDPE Pipe

A pipe is a buried or aerial pipeline carrying goods, whether in liquid or gaseous form. Pipes are most often made from polymer tubes. These pipes prove to be subject to damage caused by a lack of material or crack thus calling for methods of repair or reinforcement.The objective of this study is to analyze by finite element analysis the presence of a horizontal crack in a high-density polyethylene pipe subjected to patch-corrected internal loading.Part of this study is devoted to analyzing the Von Misses stress distribution along a horizontal line, the applied loading type effect, the orientation of the fibers and the nature of the patch have been highlighted.The second part of our study is based on the calculation of the J-Integral where the same parameters of the first part were considered.The results clearly show that the mechanical characteristics of the composite must be optimized to provide an effective repair safely and allow relief of stress concentrations at the crack front.

Fracture resistance of railway ballast rock under tensile and tear loads

The influence of loading type on tensile and tearing fracture resistance of ballast rock was assessed using edge-notched diametrically compressed disc (ENDC) and edge-notched disc bend (ENDB) test geometries. The geometry of these two specimens was similar; however, their loading type (i.e., three-point bend and diametral compressive) was different affecting the geometry factors. The obtained pure tensile fracture toughness (KIc) using the ENDB test was higher than the ENDC test. In contrast to tensile fracture toughness, the pure tearing fracture toughness (KIIIc) in the ENDC test was higher than the ENDB fracture test. The obtained experimental data were explained in terms of crack propagation path, since two distinct trajectories were observed for both configurations under tearing deformation.