In the Japanese shipbuilding industry, efforts to improve technology and productivity have been carried out recently。 One of them is the application of CIM (Computer Integrated Manufacturing) system, and the other is mechanization and robotization。 Following these applications, the next step may be simulation based design and production, considering human activity。 This paper focuses on ship production work and introduces some examples of human simulation relating to physical work such as welding, grinding and lifting。78315

Keywords: Simulation; Virtual human; Welding work; Grinding work; Lifting; Physical burden

Introduction

Since, Japan has become a nation of aged people, the shipbuilding industry now relies on aged workers who have less physical strength and also young workers who have less skill。 Thus, the worker’s age structure seems to have a wine-glass shape。

In order to increase productivity and quality, and to maintain the industrial safety and health in such situations, the current production system must be reviewed so that it will be suitable for human oriented production: easier physically for elder workers, and easier for inexperienced young workers。 Developments in biomechanics and ergonomics, together with computer simulation techniques, help to realize the newly proposed “ergofactory” which incorporates productivity and humanity (comfort) in manufacturing。

This report states firstly what will be most important, following the introduction of shipbuilding CIM (Computer Integrated Manufacturing) system, in improving the shipbuilding work in the current situation。 These improvements may include: 1。 simulation based design and production system (Okumoto, 2000; Okumoto, 2002) as a basis of virtual factory; 2。 a production system using fully applied digital manufacturing from    computer data。

Next, human task simulations have been introduced using a virtual human model on a computer, based on biomechanics and ergonomics for physical work in shipbuilding such as welding, grinding, and lifting。 These simulations include static strength predictions on a human body and the estimation of energy expenditure during such works。 Based on these analyses, a number of  preferable work  methods have  been  proposed。 The

use of such human models in research has increased recently in popularity。

This paper will help to modernize the current shipbuilding industry, which is said to be a 3-D (Dangerous, Dirty, Difficult) working environment, based on human oriented production。

Simulation Based Production

By the application of CIM system, the parts of the ship are coded numerically and defined in detail in design and production; this data set is referred to as  the product model。 Therefore, more precise production engineering becomes possible using these numerical data。 Hence, in order to raise the productivity of shipbuilding, it becomes important to examine and confirm the production process preliminarily at the early design stage using various simulations, because skilled persons of the production site become few。

Fortunately, since the capability of computers has improved remarkably in recent times, moreover, the price of computers has become cheaper, and also since the application technologies of FEM (Finite Element Method) and AI (Artificial Intelligence) have been widely spreading, computer simulations in ship production have recently become more easy。

Fig。1 shows an idea for a new ship manufacturing system。 Using the product model defined by the CIM system, simulation based design and production can be carried out, and the total optimization of the process may be achieved accordingly。 This concept is called COM (Computer Optimized Manufacturing)。 In production, the digital manufacturing will  be carried out by simulation based production and by application of recent IT (Information Technology)。