- Email: [email protected]
CAD in a Brazilian engineering firm
Comput. & Graphics Vol. 8, No. 3, pp. 227-230, 1984
0097-8493/84 $3.00 + .00 Pergamon Pre~s Lid.
Pnnled in the U.S.A.
Computer Graphics in Brazil
CAD IN A BRAZILIAN ENGINEERING FIRM ALBERTO AUGUSTO,JR.i" Promon Engenharia S.A., Silo Pauio, Brazil AbstractmAn outlined description of Promon Engenharia S.A. is given, followed by the CAD concept to be used, since there are several differing concepts. The steps which Promon took towards the use of computers in design work in the sixties, the first uses of CAD and acquisition of equipment made in the seventies as well as the course to be followed in the future are discussed. INTRODUCTION The introduction of new technologies in third world countries involves specific problems and difficulties. In this paper we shall outline the experience which Promon Engenharia S.A., a Brazilian consulting engineering firm, has had in setting up Computer Aided Design (CAD) procedures. Since it was founded in 1960 as a Brazilian-based firm of engineers and architects, Promon has responded to the growing needs of its market, both in Brazil and overseas. In its early years, the firm provided integrated engineering services to the process industries. In a short time, Promon diversified its operations to meet the needs of a growing variety of clients, both government agencies and private corporations. Today Promon is responsible for large, complex projects in such fields as process industries, mining and metallurgy, energy and hydro resources, buildings and public works, telecommunications and automation. Promon's permanent staff currently totals some 3200 employees, of which some 1200 are universitytrained professionals. THE CAD CONCEPT USED When we speak of engineering design we refer to the construction of a model of a complex physical system [1]. This model should be prepared in enough detail to allow for the construction and assembly of the system to which it is related. The physical systems normally designed by Promon are complex and involve a great number of components as well as various engineering specialties. Hierarchical breakdown is the traditional way of dealing with complex systems which have to be designed. The original problem is broken down into subproblems; each of these subproblems are, in turn, subdivided until a reasonably simple problem is arrived at. This method presents us with three basic difficulties: • Subdivision into subproblems reduces visibility, thus increasing coordination efforts. The information which gives us an overall view of the design is
l" Address correspondence to: End. R. Alvares Penteado, 97-50 Andar 01012-Centro-SfioPaulo.
scattered and great efforts are required to access, update and coordinate it. • A considerable amount of information goes from one hierarchical level to another, when the original problem is broken down. The design process is thus subject to mistakes in transcription, faulty interpretation or the omission of information. • Not all of a subproblem's variables are known and goals are not always well established. This generates interaction between subproblems of different hierarchical levels, with feedback from lower to higher levels; thus the process may not be looked upon as a linear sequence with set stages. At each subproblem level, tasks may be structured into four steps: • conception • analysis • sizing/detailing • representation In the first step, a subsystem is created which is capable of mirroring the features of the subproblem at issue. The analytic part then consists of submitting this subsystem to suitable tests which check the subsystem's validity. The subsystem is then specified in terms of its constituting elements. Finally, the subsystem is represented in reports, specifications, and especially in drawings. Wherever computing resources are used in any of the above activities, we can speak of Computer Aided Design in its widest sense. However, CAD also has a more restricted sense which we must explain. At first, computers were only used in design work as powerful calculators. Calculations which had been carried out manually were processed by machine. Calculation methods became feasible which would have been impossible without the use of a computer. For example, the finite element method was first used in structural engineering and was later adopted in other special fields such as fluid mechanics and thermodynamics. At a second stage, computers were developed which could produce engineering drawings. This was made possible due to the introduction of peripherals which allowed for man-machine graphic communication. However, it was the concept of a data base which made the next step in CAD development possible. It allowed the computer to coordinate, communicate and process technical information. A data base may
227
228
A. AUGUSTO,JR.
be thought of as a descriptive information model for a specific physical system. Using it, we can consider a new design procedure which is data-base centered rather than based on a breakdown of the hierarchy. The difficulties mentioned above, such as loss of visibility, deformation of information along a hierarchical flow and non-definition of variables of state and of objectives are thus eliminated. A design's data base provides central storage capacity for an enormous amount of information, ease in adapting models to changes, support for the geometric modeling function, rapid access to any of the parts of the model, semantic control (conflict analysis, interference, dependence, etc.), possibility of alternative solutions during certain periods of time, multiuser access, selectivity of this access to provide information security, backup facilities, recovery, reproduction, etc. The CAD concept can be situated in this context. The design is developed around a data base with the above mentioned properties and is set up by highly specialized, small teams working with integrated information and specific parameters. Detailing tasks are carried out automatically, and engineers study concepts, investigate alternatives and evaluate analytical tests. PROMON'S PRE..CAD PHASE In the sixties Promon had already begun to use computer resources in its design work. However, use of the computer was severely limited, due not only to the state of computers in engineering design itself, but also to the lack of specialized personnel and equipment within the company. Commercially available analytic programs such as STRESS were used. Some new in-house programs were developed in the fields of pipe stress analysis, continuous beam calculation and vessel calculation. PERT/CPM packages were also used. Nevertheless, the size and impact of these programs on design work was negligible. At the beginning of the seventies, the use of computers in design work began to come into its own. The company set up systems teams, developed a greater number of programs including other engineering specialties and acquired its first computer, an HP-3000. Promon was the first Brazilian consulting engineering firm to adopt a time-sharing system, thus introducing the use of interactive programs, Databased systems were set up in the fields of telecommunications and process industries. Graphic applications appeared at first with the use of off-line plotters and later with cathode ray terminals. FIRST STEPS USING CAD From 1975 on, Promon took its first steps towards setting up a Computer Aided Design program. Two factors were of prime importance, Information on experiments using CAD data based systems was now beginning to be desseminated. Carnegie Mellon University had developed the first versions of GLIDE [2], a system which was a graphics system to deal
with three-dimensional objects, a data based administration system, a high-level structured language and a CAD system. Conceptually, it was what we were looking for in a CAD system. The second factor which prompted Promon's move into CAD was the possibility of working on large engineering projects which were being undertaken in the late seventies, many of which involved the transfer of technology. As one of the largest consulting firms in the country, Promon became involved in works such as the Itaipu hydroelectric power development, large petrochemical complexes, nuclear power plants, etc. Due to its job commitments, Promon moved ahead quickly in its use of computing resources. The company could now count on a distributed computer network consisting of HP and DEC equipment, 50 in-house terminals, several graphic devices, access to large-size, third party equipment (CDC, IBM, UNIVAC) as well as access to bibliographic research systems abroad. In terms of software, Promon invested in the acquisition of basic packages (engineering monitoring systems such as GENESYS, graphic routine packages, mathematical routine packages) and in the development of large-scale programs using the finite element method, piping stress analysis, take-off counting systems, reinforced concrete beam sizing and detailing, rebar optimization and cutting programs, etc. [3-8]. Promon's use of CAD in nuclear power plant structural design is of special interest. [9] Nuclear plant structural design is much more complex than normal structural design, due specially to: ---earthquakes, which the structure must be planned to withstand; mrigorous safety measures dictated by the authorities; --large numbers of sizing standards and criteria with which the project must comply; - - t h e large number of events which affect the structure and which are represented by loading cases; mgeometric complexity of buildings housing nuclear equipment. Due to geometric complexity, the preparation of data for the finite element model is backed up by preprocessed programs which are used to maintain the consistency of data and graphically represent the model's geometry. The user can see a finite element three dimensional network on a graphical terminal or plotter. After structure processing (the inner structure of a reactor building was represented by a model with some 10,000 degrees of freedom and underwent 150 loading cases) the information generated by the finite element method analysis is organized into a data base and accessed in several post-processed programs. The amount of information may take up 50 MBytes on a disc. Post-processed programs are mainly used to calculate reinforced concrete, that is, to calculate the amount of steel reinforcement which should be placed
229
CAD in a Brazilian engineering firm
at each point of the structure. Thus, the re,suits of various loading cases are c o m b i n e d ' i 6 ~ n t actions which may act simultaneously. In the case of each loading combination, the quantities of reinforcements required are determined, and the most critical cases selected.
After concrete reinforcements have been sized and detailed, drawings of rebar lists are prepared Designers and draftsmen were trained to do this using cathode ray terminals. These automatically-produced lists facilitate reinforcement cutting, bending and assembly and elimi-
FOLHR E D I F I C ] 0 8 RUXILIARE6 RDMINISTRRTIVO6 ESCRITOR]O DO RLHOXRRIFRDO
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496.6"7
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0.0
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0.0
16.12
0.0
0.0
5.94
6
0.0
0.0
4.98
S
0.0
0.0
33.02
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0.0
4.38
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"70 Fig. 1.
230
A. AUGUSTO,JR.
nate the need to prepare drawings and sketches manually. Another advantage is the possibility of programming cutting sequences to minimize losses (see chart). THE FUTURE OF CAD AT PROMON The 80s ushered in a totally new situation in comparison with the previous decade, both in Brazil and abroad. Balance of payment difficulties hampered Brazilian imports and domestic industry does not yet produce equipment for use in CAD. On the other hand, Promon is clearly aware of the strategic importance of the introduction of CAD techniques in design development. The company intends to evolve slowly but surely in this direction. Despite the difficulties, investments are being made in interactive graphic stations and investments will be made in software and in the training of specialized CAD teams over the next four years. Today these investments are budgeted at some MU$2. In technical terms, the trend should be towards greater integration of the specialties involved in a project. Management of interferences, coordination of updating using several teams, and non-definition of alternative solutions are areas which will be left more and more for the computer to deal with. Automatic production of drawings should be extended to project areas which it does not cover at the
moment. Above all, a profound methodological change should take place with appreciable changes in the profiles of the professionals working in the design field. REFERENCES
1. L. M. G. Esmanhoto, Computer aided design--Fundamentos e tecnologia(Computer aided design-groundwork and technology). Proc. lsl CONA1, S~o Paulo (1983). 2. M. Bimbaum, el al., GLIDE--Reference Manual (1978). 3. E. Costa, et al., Bridge calculation system. Ist Sympo. on Computational Systems in Civil Engng., Rio de Janeiro (1977). 4. E. Costa, Experience on graphical applications in engineering. 1st Syrup. on Graph. Applic. by Comput., S~o Paulo (1978). 5. E. Costa et al., INTERNET: finite element network generation. 1st Sympo. on Graph. Applic. by Comput.. Sio Paulo (1978). 6. E. Costa, SINTAX: an integrated system of structural analysis. I1 Latin American Cong. on Comput. Meth. in Engng., Curitiba (1980). 7. N. Covas, DESVIGA: Desenho de Vigas de Concreto Armado (Drawings of reinforced concrete beams). II Latin American Cong. on Comput. Meth. in Engng., Curitiba (1980). 8. N. Covas, INTERNET: Gera~o de Malhas de Elementos Finitos (Generation of finite element networks). II Latin American Cong. on Comput. Method. in Engng., Curitiba (1980). 9. Projeto Estrutural de Usina Nuclear Usa CAD (Structural design of nuclear power plant uses CAD. Data News, 8(209), (6 Dec. 1983).
0097-8493/84 $3.00 + .00 Pergamon Pre~s Lid.
Pnnled in the U.S.A.
Computer Graphics in Brazil
CAD IN A BRAZILIAN ENGINEERING FIRM ALBERTO AUGUSTO,JR.i" Promon Engenharia S.A., Silo Pauio, Brazil AbstractmAn outlined description of Promon Engenharia S.A. is given, followed by the CAD concept to be used, since there are several differing concepts. The steps which Promon took towards the use of computers in design work in the sixties, the first uses of CAD and acquisition of equipment made in the seventies as well as the course to be followed in the future are discussed. INTRODUCTION The introduction of new technologies in third world countries involves specific problems and difficulties. In this paper we shall outline the experience which Promon Engenharia S.A., a Brazilian consulting engineering firm, has had in setting up Computer Aided Design (CAD) procedures. Since it was founded in 1960 as a Brazilian-based firm of engineers and architects, Promon has responded to the growing needs of its market, both in Brazil and overseas. In its early years, the firm provided integrated engineering services to the process industries. In a short time, Promon diversified its operations to meet the needs of a growing variety of clients, both government agencies and private corporations. Today Promon is responsible for large, complex projects in such fields as process industries, mining and metallurgy, energy and hydro resources, buildings and public works, telecommunications and automation. Promon's permanent staff currently totals some 3200 employees, of which some 1200 are universitytrained professionals. THE CAD CONCEPT USED When we speak of engineering design we refer to the construction of a model of a complex physical system [1]. This model should be prepared in enough detail to allow for the construction and assembly of the system to which it is related. The physical systems normally designed by Promon are complex and involve a great number of components as well as various engineering specialties. Hierarchical breakdown is the traditional way of dealing with complex systems which have to be designed. The original problem is broken down into subproblems; each of these subproblems are, in turn, subdivided until a reasonably simple problem is arrived at. This method presents us with three basic difficulties: • Subdivision into subproblems reduces visibility, thus increasing coordination efforts. The information which gives us an overall view of the design is
l" Address correspondence to: End. R. Alvares Penteado, 97-50 Andar 01012-Centro-SfioPaulo.
scattered and great efforts are required to access, update and coordinate it. • A considerable amount of information goes from one hierarchical level to another, when the original problem is broken down. The design process is thus subject to mistakes in transcription, faulty interpretation or the omission of information. • Not all of a subproblem's variables are known and goals are not always well established. This generates interaction between subproblems of different hierarchical levels, with feedback from lower to higher levels; thus the process may not be looked upon as a linear sequence with set stages. At each subproblem level, tasks may be structured into four steps: • conception • analysis • sizing/detailing • representation In the first step, a subsystem is created which is capable of mirroring the features of the subproblem at issue. The analytic part then consists of submitting this subsystem to suitable tests which check the subsystem's validity. The subsystem is then specified in terms of its constituting elements. Finally, the subsystem is represented in reports, specifications, and especially in drawings. Wherever computing resources are used in any of the above activities, we can speak of Computer Aided Design in its widest sense. However, CAD also has a more restricted sense which we must explain. At first, computers were only used in design work as powerful calculators. Calculations which had been carried out manually were processed by machine. Calculation methods became feasible which would have been impossible without the use of a computer. For example, the finite element method was first used in structural engineering and was later adopted in other special fields such as fluid mechanics and thermodynamics. At a second stage, computers were developed which could produce engineering drawings. This was made possible due to the introduction of peripherals which allowed for man-machine graphic communication. However, it was the concept of a data base which made the next step in CAD development possible. It allowed the computer to coordinate, communicate and process technical information. A data base may
227
228
A. AUGUSTO,JR.
be thought of as a descriptive information model for a specific physical system. Using it, we can consider a new design procedure which is data-base centered rather than based on a breakdown of the hierarchy. The difficulties mentioned above, such as loss of visibility, deformation of information along a hierarchical flow and non-definition of variables of state and of objectives are thus eliminated. A design's data base provides central storage capacity for an enormous amount of information, ease in adapting models to changes, support for the geometric modeling function, rapid access to any of the parts of the model, semantic control (conflict analysis, interference, dependence, etc.), possibility of alternative solutions during certain periods of time, multiuser access, selectivity of this access to provide information security, backup facilities, recovery, reproduction, etc. The CAD concept can be situated in this context. The design is developed around a data base with the above mentioned properties and is set up by highly specialized, small teams working with integrated information and specific parameters. Detailing tasks are carried out automatically, and engineers study concepts, investigate alternatives and evaluate analytical tests. PROMON'S PRE..CAD PHASE In the sixties Promon had already begun to use computer resources in its design work. However, use of the computer was severely limited, due not only to the state of computers in engineering design itself, but also to the lack of specialized personnel and equipment within the company. Commercially available analytic programs such as STRESS were used. Some new in-house programs were developed in the fields of pipe stress analysis, continuous beam calculation and vessel calculation. PERT/CPM packages were also used. Nevertheless, the size and impact of these programs on design work was negligible. At the beginning of the seventies, the use of computers in design work began to come into its own. The company set up systems teams, developed a greater number of programs including other engineering specialties and acquired its first computer, an HP-3000. Promon was the first Brazilian consulting engineering firm to adopt a time-sharing system, thus introducing the use of interactive programs, Databased systems were set up in the fields of telecommunications and process industries. Graphic applications appeared at first with the use of off-line plotters and later with cathode ray terminals. FIRST STEPS USING CAD From 1975 on, Promon took its first steps towards setting up a Computer Aided Design program. Two factors were of prime importance, Information on experiments using CAD data based systems was now beginning to be desseminated. Carnegie Mellon University had developed the first versions of GLIDE [2], a system which was a graphics system to deal
with three-dimensional objects, a data based administration system, a high-level structured language and a CAD system. Conceptually, it was what we were looking for in a CAD system. The second factor which prompted Promon's move into CAD was the possibility of working on large engineering projects which were being undertaken in the late seventies, many of which involved the transfer of technology. As one of the largest consulting firms in the country, Promon became involved in works such as the Itaipu hydroelectric power development, large petrochemical complexes, nuclear power plants, etc. Due to its job commitments, Promon moved ahead quickly in its use of computing resources. The company could now count on a distributed computer network consisting of HP and DEC equipment, 50 in-house terminals, several graphic devices, access to large-size, third party equipment (CDC, IBM, UNIVAC) as well as access to bibliographic research systems abroad. In terms of software, Promon invested in the acquisition of basic packages (engineering monitoring systems such as GENESYS, graphic routine packages, mathematical routine packages) and in the development of large-scale programs using the finite element method, piping stress analysis, take-off counting systems, reinforced concrete beam sizing and detailing, rebar optimization and cutting programs, etc. [3-8]. Promon's use of CAD in nuclear power plant structural design is of special interest. [9] Nuclear plant structural design is much more complex than normal structural design, due specially to: ---earthquakes, which the structure must be planned to withstand; mrigorous safety measures dictated by the authorities; --large numbers of sizing standards and criteria with which the project must comply; - - t h e large number of events which affect the structure and which are represented by loading cases; mgeometric complexity of buildings housing nuclear equipment. Due to geometric complexity, the preparation of data for the finite element model is backed up by preprocessed programs which are used to maintain the consistency of data and graphically represent the model's geometry. The user can see a finite element three dimensional network on a graphical terminal or plotter. After structure processing (the inner structure of a reactor building was represented by a model with some 10,000 degrees of freedom and underwent 150 loading cases) the information generated by the finite element method analysis is organized into a data base and accessed in several post-processed programs. The amount of information may take up 50 MBytes on a disc. Post-processed programs are mainly used to calculate reinforced concrete, that is, to calculate the amount of steel reinforcement which should be placed
229
CAD in a Brazilian engineering firm
at each point of the structure. Thus, the re,suits of various loading cases are c o m b i n e d ' i 6 ~ n t actions which may act simultaneously. In the case of each loading combination, the quantities of reinforcements required are determined, and the most critical cases selected.
After concrete reinforcements have been sized and detailed, drawings of rebar lists are prepared Designers and draftsmen were trained to do this using cathode ray terminals. These automatically-produced lists facilitate reinforcement cutting, bending and assembly and elimi-
FOLHR E D I F I C ] 0 8 RUXILIARE6 RDMINISTRRTIVO6 ESCRITOR]O DO RLHOXRRIFRDO
REVI8RO
RCO CORP. aJflflT| T] IITOLR UNIT
PO
(CII)
DOBRRHENT08
OROE
R
6.3
6"79
90 BO:9.1;Crl
?3
CR-50-R
~ lt~) COMER. DIM, PONTA TOTN,. 001. RLrTR (141
(CIN) 9O
1
0
30/10/80
LH-RRRIIR-11-ST-3114 LISTR NUHERO 1 DE 1
PwCl~! l
5.00
S
0.0
0.0
496.6"7
I;
0.0
0.0
8.18
6
0.0
0.0
68.63
0.0
0.0
16.12
0.0
0.0
5.94
6
0.0
0.0
4.98
S
0.0
0.0
33.02
0.0
0.0
4.38
6OO
?0
'70 2
R
6.3
409
BDd.GCN
2
2?0
?0
90 3
R
6.3
461
BO=B.ECH
13
292
OE
I
4
iz
e.o
216
7 8D=12.0CM
BO:9.GCR 6
D
6.3
99
6 95 6O
60 6
R 6.3
249
BD=O.ECN
2
160
SO
60
"7
R 6.3
264
13
6D--.8.ECM lSS BD:]2.0CM
8
D
8.0
'73
6
"70 Fig. 1.
230
A. AUGUSTO,JR.
nate the need to prepare drawings and sketches manually. Another advantage is the possibility of programming cutting sequences to minimize losses (see chart). THE FUTURE OF CAD AT PROMON The 80s ushered in a totally new situation in comparison with the previous decade, both in Brazil and abroad. Balance of payment difficulties hampered Brazilian imports and domestic industry does not yet produce equipment for use in CAD. On the other hand, Promon is clearly aware of the strategic importance of the introduction of CAD techniques in design development. The company intends to evolve slowly but surely in this direction. Despite the difficulties, investments are being made in interactive graphic stations and investments will be made in software and in the training of specialized CAD teams over the next four years. Today these investments are budgeted at some MU$2. In technical terms, the trend should be towards greater integration of the specialties involved in a project. Management of interferences, coordination of updating using several teams, and non-definition of alternative solutions are areas which will be left more and more for the computer to deal with. Automatic production of drawings should be extended to project areas which it does not cover at the
moment. Above all, a profound methodological change should take place with appreciable changes in the profiles of the professionals working in the design field. REFERENCES
1. L. M. G. Esmanhoto, Computer aided design--Fundamentos e tecnologia(Computer aided design-groundwork and technology). Proc. lsl CONA1, S~o Paulo (1983). 2. M. Bimbaum, el al., GLIDE--Reference Manual (1978). 3. E. Costa, et al., Bridge calculation system. Ist Sympo. on Computational Systems in Civil Engng., Rio de Janeiro (1977). 4. E. Costa, Experience on graphical applications in engineering. 1st Syrup. on Graph. Applic. by Comput., S~o Paulo (1978). 5. E. Costa et al., INTERNET: finite element network generation. 1st Sympo. on Graph. Applic. by Comput.. Sio Paulo (1978). 6. E. Costa, SINTAX: an integrated system of structural analysis. I1 Latin American Cong. on Comput. Meth. in Engng., Curitiba (1980). 7. N. Covas, DESVIGA: Desenho de Vigas de Concreto Armado (Drawings of reinforced concrete beams). II Latin American Cong. on Comput. Meth. in Engng., Curitiba (1980). 8. N. Covas, INTERNET: Gera~o de Malhas de Elementos Finitos (Generation of finite element networks). II Latin American Cong. on Comput. Method. in Engng., Curitiba (1980). 9. Projeto Estrutural de Usina Nuclear Usa CAD (Structural design of nuclear power plant uses CAD. Data News, 8(209), (6 Dec. 1983).