Hull Bending Moment Due to Ship Bottom Slamming in Regular Waves

1975 ◽  
Vol 19 (02) ◽  
pp. 80-92
Author(s):  
A. Mansour ◽  
J. M. d'Oliveira
Keyword(s):  
Physical Model ◽  
Mathematical Formulation ◽  
Time History ◽  
Bending Moment ◽  
Regular Waves ◽  
Hydrodynamic Problem ◽  
Overall Response ◽  
Behavior Based ◽  
Definition Of

A review of the existing literature on the overall response of ships to bottom slamming is presented. A mathematical formulation of the vibratory bending moment due to bottom impact slamming in regular waves is then developed. The hydrodynamic problem concerning the definition of the loads is first discussed and a particular physical model is adopted for determining the hull vibratory behavior. Based on this formulation, a general computerized procedure leading to the time-history representation of the midship bending moment is developed. Finally, an illustrative example of application to a Mariner ship is described and the results are related to some available data.

scholarly journals Superelement Verification in Complex Structural Models

2008 ◽  
Vol 15 (3-4) ◽  
pp. 369-381 ◽  
Author(s):  
B. Dupont ◽  
E. Pillet ◽  
S. Cogan
Keyword(s):  
Approximate Solution ◽  
Physical Model ◽  
Structural Models ◽  
Response Prediction ◽  
Prediction Errors ◽  
Structural Assembly ◽  
Complex Structural ◽  
Natural Result ◽  
Definition Of

The objective of this article is to propose decision indicators to guide the analyst in the optimal definition of an ensemble of superelements in a complex structural assembly. These indicators are constructed based on comparisons between the unreduced physical model and the approximate solution provided by a nominally reduced superelement model. First, the low contribution substructure slave modes are filtered. Then, the minimum dynamical residual expansion is used to localize the superelements which are the most responsible for the response prediction errors. Moreover, it is shown that static residual vectors, which are a natural result of these calculations, can be included to represent the contribution of important truncated slave modes and consequently correct the deficient superelements. The proposed methodology is illustrated on a subassembly of an aeroengine model.

The Use of Photogrammetry in Piping Design

1983 ◽  
Vol 197 (2) ◽  
pp. 125-138 ◽  
Author(s):  
P A Bracewell ◽  
U R Klement
Keyword(s):  
Information Retrieval ◽  
Mathematical Formulation ◽  
Three Dimensional ◽  
Cost Effective ◽  
Process Industry ◽  
Process Plant ◽  
Definition Of ◽  
High Degree ◽  
Positional Data

Piping design for ‘revamp’ projects in the process industry requires the retrieval of large amounts of ‘as-built’ data from existing process plant installations. Positional data with a high degree of accuracy are required. Photogrammetry, the science of measurement from photographs, was identified in Imperial Chemical Industries plc (ICI) as a suitable tool for information retrieval. The mathematical formulation enabling the definition of three-dimensional positions from photographic information is described. The process of using ICI's photogrammetric system for the definition of complete objects such as structures and pipes is illustrated. The need for specialized photogrammetric software for design purposes is explained. A case study describing how the photogrammetric system has been applied is described and graphical outputs from this exercise are shown. It is concluded that this particular photogrammetric system has proved to be a cost effective and accurate tool for the retrieval of ‘as-built’ information.

scholarly journals Dynamic Response Evaluation of Long-Span Reinforced Arch Bridges Subjected to Near- and Far-Field Ground Motions

2018 ◽  
Vol 8 (8) ◽  
pp. 1243 ◽  
Author(s):  
Iman Mohseni ◽  
Hamidreza Lashkariani ◽  
Junsuk Kang ◽  
Thomas Kang
Keyword(s):  
Ground Motion ◽  
Dynamic Performance ◽  
Time History ◽  
Bending Moment ◽  
Element Model ◽  
Structural Performance ◽  
Far Field ◽  
Inelastic Behavior ◽  
Earthquake Loads ◽  
Arch Bridges

This study assessed the structural performance of reinforced concrete (RC) arch bridges under strong ground motion. A detailed three-dimensional finite element model of a 400 m RC arch bridge with composite superstructure and double RC piers was developed and its behavior when subjected to strong earthquakes examined. Two sets of ground motion records were applied to simulate pulse-type near- and far-field motions. The inelastic behavior of the concrete elements was then evaluated via a seismic time history analysis. The concept of Demand to Capacity Ratios (DCR) was utilized to produce an initial estimate of the dynamic performance of the structure, emphasizing the importance of capacity distribution of force and bending moment within the RC arch and the springings and piers of the bridge. The results showed that the earthquake loads, broadly categorized as near- and far-field earthquake loads, changed a number of the bridge’s characteristics and hence its structural performance.

Bruton tyrosine kinase inhibitors (BTKi) therapies in chronic lymphocytic leukemia (CLL): Review of multiple trials data for incidence of lymphocytosis and designation of partial response with lymphocytosis (PRL).

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. e19502-e19502
Author(s):  
Jayant Narang ◽  
Christiana Caplan ◽  
Katarina Ludajic ◽  
Sambit Ray ◽  
Surabhi Bajpai ◽  
...  
Keyword(s):  
Partial Response ◽  
Kinase Inhibitors ◽  
Absolute Lymphocyte Count ◽  
Lymphocytic Leukemia ◽  
Additional Parameter ◽  
True Incidence ◽  
Overall Response ◽  
Group A ◽  
Definition Of ◽  
Group B

e19502 Background: In trials with BTKi, lymphocytosis alone may not be a sign of progression but rather treatment related redistribution of lymphocytes from tissues into the peripheral blood (Cheson et al 2012). This observation was later incorporated in iwCLL 2018 criteria. However, no clear details were provided on how to assess lymphocytosis along with other parameters to derive an overall timepoint response (OTR) in a clinical trial setting. While PRL is a response category used to assess lymphocytosis in many clinical trials, it has not been defined in iwCLL 2018. Furthermore, iwCLL 2018 defines Absolute Lymphocyte Count (ALC) progression (PD) as an increase of ALC ≥ 50% compared to baseline whereas conventionally progression is defined in comparison to nadir, which may lead to under reporting of ALC PD. Methods: Data from multiple (8) phase II/III CLL trials with BTKi (frontline and relapsed/refractory setting), were retrospectively analyzed. Subjects with a post baseline (post-BL) timepoint (TP) were analyzed for the incidence of ALC PD and an OTR designation of PRL, PD and other non-PD assessments (Stable Disease (SD), Non-PD and Unknown (UNK)). Results: We identified 1976 subjects with a total of 17134 post BL TPs. There were 1182 TPs (6%) with ALC PD. Out of these TPs with ALC PD, 497 TPs had OTR of PRL (42% TPs with ALC PD), 365 TPs (31%) were assessed as non-PD and 320 (27%) TPs were assessed as PD. 104 TPs (33%) of subjects with OTR of PD had at least one additional parameter driving PD. Thus, ALC PD is a common occurrence with BTKi and in line with the Cheson 2012 guidance, ALC PD alone should not be considered as overall progression. We propose that initial ALC PD with BTKi should not be considered a sign of progression but rather a treatment effect and should be assessed as PRL. However, PRL should only be assessed if Partial Response (PR) is achieved in at least 2 other involved iwCLL group A parameters (nodes, liver or spleen) and 1 group B parameter (hemoglobin or platelets). An initial decrease/normalization of the ALC compared to baseline with a subsequent progression compared to nadir, may be considered true progression in a setting of continued BTKi. If only one other group A parameter is involved and is PR with associated ALC PD, SD may be a more appropriate overall response than PRL. Conclusions: ALC PD and PRL are common in BTKi, but there is a need for standardization of the definition of ALC PD and its role in determination of OTR of PRL. We propose that ALC PD should be assessed by comparing ALC with nadir and not baseline. If PRL is assigned only when PR is met by other criteria along with ALC PD, PRL could be a part of determining Overall response rate (ORR) in protocols. Future prospective studies are needed to estimate the true incidence of ALC PD and its impact on ORR with BTKi as well as other agents which induce lymphocytosis.

Force Analysis of the Anchor Chains and the Cable in the Crane-System with a Floating Base in Regular Waves

2014 ◽  
Vol 494-495 ◽  
pp. 321-327
Author(s):  
Ya Xin Huang ◽  
Bing Wang ◽  
Jun Yi Liu
Keyword(s):  
Numerical Simulation ◽  
Discrete Time ◽  
Time History ◽  
Roll Motion ◽  
Force Analysis ◽  
Time Transfer ◽  
Regular Waves ◽  
Body Model ◽  
Floating Base ◽  
Rigid Body Model

In order to analyze the force of the anchor chains and the cable in the crane-system with a floating base, firstly the system is simplified to two-rigid-body model and the anchor chains in the system are in symmetric layout; then the motion response of the system as well as the force of the anchor chains and the cable are solved by use of discrete time transfer matrix method, lastly the time history curves of motion of the system and the force of the anchor chains and the cable are obtained. The results of numerical simulation show that the roll motion has greater influences on the system comparing with sway and heave, the amplitudes of sway and heave are small. Furthermore, the force of the anchor chains are mainly caused by the roll motion while the force caused by sway and heave are relatively small.

Wave Induced Pressures on Pipelines Near a Sloping Boundary Due to Regular Waves

2002 ◽  
Author(s):  
K. A. Roopsekhar ◽  
V. Sundar
Keyword(s):  
Time History ◽  
Wave Direction ◽  
Regular Waves ◽  
Scattering Parameter ◽  
Similarity Parameter ◽  
Experimental Procedure ◽  
Sloping Bed ◽  
Model Setup ◽  
Force Time ◽  
Wave Induced

The hydrodynamic pressures due to regular waves around the circumference of a pipeline near a sloping rigid bed and placed parallel to the wave direction have been measured. The pressures were integrated to obtain the force time history, from which the peak horizontal and vertical forces were evaluated. The effects of relative clearance of pipe from the bed and its relative position from the toe of the sloping bed on the pressures and forces on the pipeline as a function scattering parameter and wave steepness are reported. The reflection characteristics of the sloping bed in the presence of the pipeline are reported as a function of surf similarity parameter and compared with the results from existing literature. The details of the model setup, experimental procedure, results and discussion are presented in this paper.

scholarly journals Seismic Effectiveness of Multiple Seismic Measures on a Continuous Girder Bridge

2020 ◽  
Vol 10 (2) ◽  
pp. 624 ◽  
Author(s):  
Yumin Zhang ◽  
Yun Shi ◽  
Dengke Liu
Keyword(s):  
Time History ◽  
Bending Moment ◽  
Large Earthquake ◽  
Economic Losses ◽  
Bridge Structure ◽  
Expansion Joint ◽  
Maximum Reduction ◽  
Joint Application ◽  
Safety Research ◽  
Joint Displacement

Seismic hazards, such as bridge pounding, unseating, collapse, etc., cause significant economic losses and affect traffic and safety. Research on seismic measures, such as limiting and unseating prevention devices for the bridge, can effectively prevent damage to the bearings, such as excessive displacement, the pounding of the beam end, etc., in an earthquake. In this paper, the dynamic time-history analysis method was used to study the mechanical behaviors of the bridge structure, such as its seismic performance, structural displacement, pier bending moment, etc. We found that different combinations of seismic measures can effectively reduce the displacement at the bridge expansion joint and bearings. The joint application of an expansion device, restrainer, and unseating prevention devices shows the best limiting effect on bridge displacement and expansion joint displacement. The maximum reduction of bridge expansion joint displacement reaches 48% and is within the allowable deformation range of an expansion device in a large earthquake, and the maximum reduction of bearing displacement reaches 34%, which only slightly exceeds the shear deformation of the bearing. The expansion device, restrainer, and unseating prevention devices have smaller internal forces in this case than other cases, without damage. In contrast to the previous studies on single seismic measures of unseating restrainers, this study investigates the combination of multiple seismic measures and earthquakes of various magnitude. It reveals the catastrophe process of the bridge structure and the cooperation law of seismic measures in an earthquake.

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