transverse bulkheads (at each station from 0#~20#) were used  to reinforce the transverse stiffness of  the   model

measures the weighted average  of

where ballast blocks were located。 The weight and    lo-

cations of the ballast blocks were suitably arranged to satisfy the similitude of the longitudinal weight distri- bution and the position of the centre of gravity of the

the functionnear the ‘jth ’ point of the data set on

ship。 Chen et al (2001) describes in detail the   principal

frequency level (n-1), and  c j

measures the weighted

particulars of the S175 container ship and the flexible

change in the function near the ‘jth’ point。

Repetition  of  this  procedure  for  the  term    including

nm

model manufacturing process。

The model was self-propelled, travelling with the car- riage,  and  allowed  to  freely  surge,  heave,  pitch  and

a j , m  1,。。, n

and  accounting for  the periodic  be-

vibrate  vertically。  Sway,  roll  and  yaw  motions  were

haviour of the extended series of samples, the signal expression takes the form

restricted。 The speed of the model was set for a pre- scribed  propeller  revolution  rate  of  the  ship  and was

measured by the speed of the towing carriage。

Stresses, vertical bending moments, vertical accelera- tions  at  the  FP,  and  heave  and  pitch  motions   were

measured。 The 2-node frequency of the ship model floating  in  still  water  and,  the  vertical  steady    state

bending  moment  due  to  the forward  speed  were also

  

measured。 The heave and pitch motions were  measured

ponent motion measuring device。 A servo needle type wave height meter was firmly attached to the towing carriage with the probe positioned    approxi-

mately 4。5m in front of the model’s centre of gravity。文献综述

Vertical accelerations were measured by an acceler- ometer installed on the deck at the centreplane of Sta-

tion 20。 The bending moments were measured   through

Eq。 7 represents a linear operation and provides the wavelet expression describing a series of data by a se- ries of functions originally arising from a base of scal- ing functions and wavelet functions by shifting and compressing the independent variable x。 At each fre- quency level n-m (m=1, 2, …, n+1), the basis functions

strain gauges fixed on the starboard side-deck plate at

longitudinal stations。 The relation between the vertical bending moment and the value of strain was derived by a static calibration method assuming that the  creepage of the material is small and can be neglected。 The loca- tions of these measurement points were:

M1 near Station 15 (2。65m from AP); M2   at Station 12。5;

M3 near Station 10 (1。85m from AP); M4   at Station 7。5;

M5   near Station 5  (0。95m from AP)。

The experimental conditions for the S175 container ship model travelling at Fn=0。275 in regular head waves are listed in Table 1(: wavelength, a: wave amplitude)。

Table 1:  Experimental test conditions

Head sea, Fn=0。275

Case 2a/ Lpp