Approaches of these types would be of value in planning and executing 

 seafloor operations and in designing penetrators for use as seafloor 

 survey tools • 



The analysis of the data, therefore, was divided into two general 

 areas. In the first, the accelerometer records were analyzed 

 statistically using regression analysis in an attempt to derive general 

 parameters which would be representative of soil and penetrator 

 characteristics. In the second area of analysis, the soil and penetrator 

 characteristics were inserted into several rational penetration 

 equations, and the resulting theoretical acceleration versus depth 

 plots were compared with the actual measured accelerometer data. 

 The results of these two analyses are included in the following sections 

 and a discussion of the implications of the results is included in 

 the DISCUSSION section. 



Regression Analysis 



Using the procedure outlined in the REDUCTION discussion, 

 acceleration, velocity, and displacement were calculated for each 

 test. Also, each set of test data was divided into a water region 

 and a soil penetration region. The next phase of the investigation 

 was to develop a means to evaluate the data. 



The approach that was employed was to examine the forces acting 

 on the object and develop an appropriate force equation. The basic 

 equation of interest was that forces on the object must equal the 

 mass of the object times its acceleration. The question then arises, 

 which forces are acting on the object? Solely in the water, there 

 are two: driving force (buoyancy and weight lumped together) and 

 drag force. As the object enters the soil, however, there are various 

 soil forces encountered in addition to the solely water forces 

 (hydrodynamic forces). These soil forces include wall friction, 

 frontal resistance and inertial forces. 



I F = ma = F^ + F^ + Fg^ + F^^ + F^ (2) 



where F = force, pounds 



m = mass , slugs 



a = acceleration, feet per second per second 



F = driving force which reflects the weight of object and 

 the buoyancy of the object in water 



F = water drag force on the surface of the object 

 H 



F„„ = frictional force on the walls of the object produced 

 Sw , , . T 

 by the soil 



