Abstract: Motion response of floating structures is of great
concern in marine engineering. Nonlinearity is an inherent property
of any floating bodies subjected to irregular waves. These floating
structures are continuously subjected to environmental loadings from
wave, current, wind etc. This can result in undesirable motions of the
vessel which may challenge the operability. For a floating body to
remain in its position, it should be able to induce a restoring force
when displaced. Mooring is provided to enable this restoring force.
This paper discusses the hydrodynamic performance and motion
characteristics of an 8 point spread mooring system applied to a pipe
laying barge operating in the West African sea. The modelling of the
barge is done using a computer aided-design (CAD) software
RHINOCEROS. Irregular waves are generated using a suitable wave
spectrum. Both frequency domain and time domain analysis is done.
Numerical simulations based on potential theory are carried out to
find the responses and hydrodynamic performance of the barge in
both free floating as well as moored conditions. Initially, potential
flow frequency domain analysis is done to obtain the Response
Amplitude Operator (RAO) which gives an idea about the structural
motion in free floating state. RAOs for different wave headings are
analyzed. In the following step, a time domain analysis is carried out
to obtain the responses of the structure in the moored condition. In
this study, wave induced motions are only taken into consideration.
Wind and current loads are ruled out and shall be included in further
studies. For the current study, 2000 seconds simulation is taken. The
results represent wave induced motion responses, mooring line
tensions and identify critical mooring lines.
Abstract: An attempt in this paper proposes a re-modification to
the minimum moment approach of resource leveling which is a modified minimum moment approach to the traditional method by
Harris. The method is based on critical path method. The new approach suggests the difference between the methods in the
selection criteria of activity which needs to be shifted for leveling resource histogram. In traditional method, the improvement factor
found first to select the activity for each possible day of shifting. In
modified method maximum value of the product of Resources Rate
and Free Float was found first and improvement factor is then
calculated for that activity which needs to be shifted. In the proposed
method the activity to be selected first for shifting is based on the largest value of resource rate. The process is repeated for all the
remaining activities for possible shifting to get updated histogram.
The proposed method significantly reduces the number of iterations
and is easier for manual computations.