OBJECTIVES OF TREE METHODS

PRESENTED BY

JAGADISH (ME09307)

BHAGWAT (MEO933O6)

•It shows the objectives in a diagrammatic or in a tree structure or hierarchical pattern hence it is called as objective tree method.

•The aim of this method is to clarify the design objectives and sub-objectives and the relationship between them.

• It shows the objectives and general means for achieving them, which are in consideration.

WHAT IS OBJECTIVE TREE METHODS ?

PROCEDURE OF OBJECTIVES TREE METHOD

• Prepare a List of Design Objectives (Client or Your Advisor Requirements, User Needs or Product Purpose).

– Some from the design brief– Others by questioning the client – More by discussion in the design team

• Group the Objectives into Sets of hierarchical levels, each concerned with one Highest-Level Objective.

• Draw Tree of Objectives, showing hierarchical relationships and interconnections.

• Main objective – m/c tool must be safe and reliable• Its sub-objectives are,

- Low risk of injury to the operator. - Low risk of operator mistake. - Low risk of damage to work piece or tool. - Automatic cut-out overload.

Step2: Order the list into sets of higher level & lower level objectives.

-It must be safe. -Low risk of injury to the operator. -Low risk of operator mistake. -Low risk of damage to work piece or tool. -Automatic cut-out overload.

EX. MACHINE TOOL.

Step1: Prepare list of design objectives

STEP 3. Drawing of tree structure

mmmmaccMachine must be safe

Low Low risk of injury to oprator

Low risk of injury to oprator

Low risk of damage to workpice or tool

Outmatic cut-out on overload

‘HOW’

‘WHY’

Fig- Hierarchical diagram of relationship between objectives.

Low risk of operator mistake

EX. HIGH PRESSURE PUMP

• Client’s Requirements:

1. Rationalize range of pumps to reduce manufacturing costs (Standardization)

2. Improve Reliability

3. Convenient to varied and changing needs of customers

DESIGNERS’ ELABORATIONS

1. By Reliable & Convenient client means robust (not easily fail)

2. Initial List of Objectives becomes:

1. Reliable

2. Convenient

1. Robust

3. Standardized Range

ELABORATIONS ON INITIAL OBJECTIVES

• Investigating problems with existing pumps revealed that thermal expansion of connecting pipes generates thermal stresses that can cause cracking & leakages. Consequently robustness & reliability were requested • Investigating convenience objective revealed another two

sub-objectives:

– Pumps should be easy to install & replace

– Pumps should occupy the minimum space

EXPANDED LIST OF OBJECTIVES:

1. Reliable Robust

Resistant to external mechanical stresses

Unaffected by thermal expansion of pipes

2. Convenient

Easy to install & replace

Occupy minimum space

3. Standardized Range

RELIABLE

ROBUST

RESISTANCE TO EXTERNAL

MECHANICAL STRESSES

UNAFFECTED BY THERMAL

EXPANSION

CONVENIENT

EASY TO HANDLE

NSTALLED INLINE

WITH PIPELINE

S

OCCUPIES MINIMUM

SPACE

SMALL BASE

MODULAR

RANGE OF

SIZES

Objective tree for high pressure pump

DESIGN FOR SAFE LADDER

QUESTIONS

THANK YOU!