Quiet fall life on Lulu Island and Stressmen 13

Oval is opened and ready for the 2010:

The doors are really opened and you can come in:

Nice modern facilities inside but I prefer my outside exercises in the places like this:

Then it’s great to watch pilots landing skills together with eagles:

Or other pilot technique to navigate this huge bulker through our delta:

The story is continued with Stressmen 13

There were many other interesting problems in the Ilyushin Design Bureau in the end of seventies. One of them, analysis of the Il-102 frame, gave me a chance to look at very unusual structure. Ground attack aircraft had armor panels as fuselage structural elements. The wing had huge landing gear what left nothing except leading edge for torsion balancing. But it worked and only small modifications of the initial project were done on the base of our analysis and airplane was built. Looking ugly with its humped fuselage it was sitting in the assembling rig close to the Il-86.

Same time Volodya Peresypkin was looking for the effective wing structural scheme for the future Il-96. Solovov’s sandwich element was used for this purpose. Analysis of internal forces and theoretical material distribution gave good hint for the new scheme. Different backswept wing boxes with landing gear beam were analyzed too. All of them including Il-86, Boeing-707, Boeing-747, A-300 showed that there is undesirable interaction between landing gear beam and wing box in the area where beam is attached to the rear spar. The new scheme was found with small triangle thin-wall box behind the spar between spar and beam, which makes this interaction softer. The scheme was protected by patent and really implemented in the Il-96 wing structure.

Trips to Moscow were often. I liked Ilyushin Design Bureau and used every opportunity to walk through its experimental plant to see what new they have in production. Huge rigs for the Il-86 and small for the Il-102, the riveting, cutting, stamping, machining, assembling – I still remember sounds and smells of this walk. During lunch time we visited very nice canteen with good food that was much diverse and tastier than we had in KuAI. Moscow was announced as a “city of communist style of life” and Muscovites really lived better life than people from the provinces.

Ilyushins used not only PRASAK in that time, but Systema-4 which was TsAGI’s production, created by Vitaly Chuban’s team. It was written in FORTRAN for the BESM-6, Soviet super computer. I liked to go to BESM-6 hall to see this giant alive. But Our M-220 was situated on the B territory, 15 minutes walk from main facilities. And we liked this too as it gave us a chance for shopping and even drinking couple of beers on the way from one place to another.

There were several places for beer drinking in vicinity of Central Aerodrome area. The most popular between us was a very simple beer-bar in Petrovsky Park near Petrovsky Palace which was occupied by Air Force Academy named after Ghukovsky. Great Russian history is presented here everywhere. It was pleasant to drink the bear in the place that is surrounded by Russian aviation historical artifacts and discuss current aviation problems that really face us. Many solutions were found here during friendly conversations supported by Ghigulevsky beer and pickled herring on the piece of black bread.

Fall Urban Views and Stressmen 12

Rainy day in Vancouver is what we got used too. And I like such days and my walk in Kitsilano Beach and Granville Island in rainy weather.

The harbor is very quiet:

Downtown looks attractive from under the bridge:

Aquabus has rainbow colors what makes it cheerful:

This boat had a very high tide one day:

Granville Island is wearing fall colors:

And I continue my story, Stressmen 12

One morning at the end of November 1977 Ekaterina Alekseevna told me that I have to go to Moscow and resolve the problem of the Il-86 nose landing gear box collapse.

“Last night Abramov gave a call and informed me that during towing test they turned the nose leg inside out. Ghenya Makeev and Nina Kell will go with you. You have to create the model, simulate the test, understand well the reasons of the failure and find repair variants in two weeks” – was the order.

In the next day morning Aeroflot’s Tu-154B brought our team to Domodedovo airport. We took the bus outside the terminal and in one and half hour arrived to the Ilyushins Design Bureau check-point. Our passports and so called warrants were examined and recorded, the First Department (State Security) certificates taken out to be returned on our way back. Only after this we got our passes to enter inside the fence.

The Airframe Strength team was situated on the second floor of the old design office building. Valery Ivanovich was glad to see us:

“Let’s go and have a look at the airplane” – was his proposal after several words of greeting.

“OK, but let’s take our hotel orders on the way” – I answered, knowing well, that if we do not do this now, later they will close the service office and we will sleep on the street.

“Yes, let’s do this too. But sorry, guys, all rooms on Pilot Nesterov Street are occupied now, therefore we booked your rooms in Zarya.

“Holly smoke! Have you ever been there yourself?” – Ghenka exclaimed. We had the experience of staying in these Altay, Vostok, Zarya row of hotels that were built for 1957 World Youth Festival and well known now as a chip places that are very popular between people from Caucasus and Middle Asia Republics.

“What can I do, guys! I have no hotel and my two bedroom apartment is not good for your staying too”.

“OK, we will survive this time as did this before” – I put a period into discussion.

And the work started.

The front leg niche (thin wall box type of structure) is pressurized as it is situated in the fuselage pressurized area. The thin wall structure was stiffened by ribs, positioned inside the fuselage, leaving outside wall surfaces smooth. The stiffening of the box was designed to prevent buckling of this thin wall structure under internal fuselage pressure. Working very closely with designers, who provided us with geometrical and material data, we created finite element model during the first week. Then, through calculations, we found that ground towing load case leads to high compressions in some areas of the box structure, which never happens in flight conditions with pressurized fuselage. This compression was a reason of buckling and structural collapse. The effective repair variant was found too, what was reinforcement of the existing system of stiffeners in particular area.

Beautiful Fall and Stressmen 11

It was a nice walk in the neighborhood. What the impressive colors around! Look at this:

And at this:

The bays are covered by thin veil of mist:

And forest is really golden:

And this is continuation, Stressmen 11

My first scientific public presentation happened at TsAGI’s “Young Scientists Conference”, which Sergey Rychkov and I attended in 1978. I reported on the issues of the Il-76 wing-fuselage interface and its modification, Sergey presented problems of the Il-86 rear fuselage structure and fuselage-empennage interaction.

We arrived to Moscow week earlier with our usual tasks at Ilyushins. The conference placards were prepared in the company’s hotel room on the 7 Pilot Nesterov street at night time after our main work in design office. The conference took place in the TsAGI’s Palace of Culture in Ghukosky downtown. Electrical train was common means of transportation to this place from Moscow. You have to take it on Kazansky railway station and in one hour of pleasant trip in Moscow suburbs the Otdykh (The Rest) platform surrounded by pine forest is a place of your destination. I like the walk from railway platform to TsAGI through pine forest and quiet small town streets.

The personnel of the TsAGI’s third department were our major listeners, reviewers, referees and critics. Vladimir Fedorovich Kutyinov, the Head of this department, paid attention to the event and asked his people to take part in the conference actively. Therefore it was a chance for me to make acquaintance with Georgy Zamula, Eugeniy Lipin, Victor Biryuk and other TsAGI leads. There were many questions to the presentation, our illustrations of structural behavior were really interesting for audience. Georgy Zamula stressed importance of detailed structural analysis on the base of finite element calculations. He praised our reports and told that these are examples of structural analysis he would like to see his guys provided him.

Conference banquet was very impressive by its excellent buffet with big amount of food and drinks. But, what was really important, there were many young engineers and researchers, not all of them mails, good music and very good new acquaintance.

After successful presentation in TsAGI I had another public affair: examination on the Marxist Leninist Philosophy. We had it on Tuesday of the week after our return from Moscow. Of course I was not prepared but something told me that this test can’t be serious. The event took part in the philosophy classroom in the first building of KuAI. Docent Taller met us and we got our questions. I read them and then started to look on the walls which were covered by placards with major dogmas and communist leaders’ citations. Of course I found several of them that suited to my questions. And when docent asked if somebody is ready I raised my hand.

Robert Taller looked at my piece of paper and understood the situation clearly. But instead of asking additional questions and digging dipper into my knowledge of the subject he started conversation about my research work. I told him the fresh story of my participation in the conference and what kind of research I reported there. He was really interested and asked many questions about the Il-76 structure, the situation in the Ilyushin design bureau and my future career in structural analysis field. We spend ten minutes in this conversation when Docent Kwitnoy entered the room. Robert took my student record-book and announced:

“Excellent”

But Mr. Kwitnoy stopped him by saying:

“Wait, wait, let me have a look”.

He took my paper, had a look, understood everything and acted in a wink:

“Tell me, what else Vladimir Ilyich told about class definition except what you rewrote from the wall?”

I had no answer to this question ant to three other questions he asked me after first one.

“Very bad” – was his verdict and he tried to take my record-book from Robert’s hands. But Robert kept it and asked to step out for negotiations. They went out the room and in couple of minutes returned back. Robert announced:

“Passably” – and put mark into examination log and into my record-book.

I do not know what kind of discussion they had, but of course I was mad about Kwitnoy uprising in examination room. It was upset event but I forget about this in fifteen minutes after returning to my routines of NIG-1 research duties.

Walking in the rain and Stressmen 10

It was hot and dry summer this year. September and half of October were unusually dry and warm too. But finally rain came back and we have usual weather which still pleasant for cows in Delta:

And it still pleasant to walk in parks like this:

And of course, in the forest:

Such walks helps to remember some events, therefore I continue, Stressmen 10

The Il-76 was not the only problem that NIG-1 had in hands in those times. Sergey Rychkov analyzed the rear fuselage of the Il-86, Russian “respond” to the A-300. The first assembled airframe of the Il-86 was tested for static load cases in the Inlyshin’s huge testing facilities close to assembling shop and there were several problems with the structure. Volodya Peresypking managed engineering aspects, Katya Ivanona provided administrations. She pushed Volodya to start writing his PhD thesis. And in parallel to this very important problem of the future Il-96 wing to fuselage interface was under analysis and optimization in the NIG-1 too.

Our travels to Moscow were often. We prefer to take train as a mean of transportation. It took us 18 hour by “Ghiguly” speed train to reach Moscow. You board the train in Kuibyshev in the afternoon and next early morning step off on the platform of Kazanskaya Station in Moscow. Comfortable enough compartments gave you a chance to have good chat, informal information exchange, and even some rest and good sleeping. There was one other reason why we liked railway better than air transportation. There was shortage of the food and goods in the USSR in that time. But Moscow, as a city of communist style of life, was supplied much well than other cities and regions of the country. Therefore every trip to Moscow was the trip for shopping. For example, I had special 60 liter backpack for my Moscow travels. And every time on my way back it was filled up with such things like apples, oranges, meat, coffee, candies, cheese, bananas, sausage, bottles of vines and other similar stuff. The weight of such loaded backpack can be heavier than 40 kilograms, but Aeroflot, the only airline in the Soviet Union, allowed you to take 20 kilograms aboard and the price for extra weight was high enough.

NIG-1 as a scientific research group had to have personnel with highest level of qualification. There were two doctorate degrees in the USSR and still are two in Russia: Candidate of Science, what is equivalent to the Western PhD, and Doctor of Science, what is higher than PhD and has no equivalent in North America, but has something similar in Germany and France. Being researcher we were motivated to get doctorate degree, but this was not simple. First of all we had to attend two courses: English language and Marxist Philosophy and then, finishing them, took two examinations on these subjects. We were assigned to this course together with Sergey Rychkov. English language lessons were very interesting for me. I understood importance of English for my career. But it was obvious for me even in the middle of 70s that Marxist Philosophy was absolutely inapplicable to real life. I attended only one lesson of Professor Taller and understood well that he has same opinion.

And of course, being researches we had to take part in conferences with our own reports. Publishing of our articles was compulsory too. One of my first scientific papers was written in collaboration with Valery Mischuk and Volodya Peresypkin. It is based on the analysis of the Il-76 wing to fuselage interface.

Fall colors and Stressmen 9

I like this bog area on Lulu Island:

It’s interesting that blueberries are still here:

And they are tasty:

And I continue the story, Stressmen 9

3. PRASAK time

My first serious structural analysis task was related to the Il-76 wing-fuselage interface. The ground fatigue test revealed low life for several primary structural elements in the zone where the fuselage was attached to the wing. First of all it was the upper part of the frame #41, which is the main frame attached to the rear wing spar. There was a fast propagating crack in the frame web.

Drag angle that connected stringer #9 and rib #4 had fatigue damages too. And there were two more places with fatigue problems: fasteners that connected stringers #0 and #2 to wing ribs and panels, and insulation web between rear spar and fuselage flat pressurized panel behind the wing.

NIG-1 office was situated in the KuAI’s building #3 on Moskovskoe Shosse street but BESM-4 was placed in the building #1 in Kuibyshev downtown on Molodogvardeiskaya street. This means that we traveled often in the city. But the major peculiarity of our computer work was its scheduling for the night shifts. For several years I had approximately one night shift per week. And this was not only for me but for major personnel of the NIG-1.

Soon we got another computer with M-20 command system. It was M-222, a little bit advanced in comparison with BESM-4, with magnetic dram and wider magnetic tapes, what made it faster.

My new task demanded often travels to the Ilyushin Design Bureau. They were situated in Moscow near central airfield the former Khodynskoe Pole. Sukhoy, Yakovlev and Mikoyan are placed near by too. The Ilyushin’s “strength of the airframe” brigade headed by Valery Abramov were our clients. Finite element method was not popular in the design bureau in that time. Most of analyses were hand calculations. Certification requirements were covered by natural tests. For the Il-76 fatigue evaluation they used to stands: fuselage and wing. The fuselage stand included the major portion of the fuselage itself and short wing imitator. And wing test consisted of the wing itself and short part of the central fuselage.

Our model was much more accurate for wing-fuselage interface analysis in comparison with what analytical methods. And very soon we proved that there are stress concentration in the fatigue damaged areas. Visualization of the displacements and stresses in the area revealed the reasons of crack concentrations very soon. Our illustrations were used for repair decision making.

Russian geese back and Stressmen 8

Russian snow geese arrived:

I call them Russian because they were born in Russia on the Wrangler Island. It looks that they like Lulu Island and enjoy their staying here:

My story is continued, Stressmen 8

Sergey Rychkov graduated from KuAI one year later than I but he wasn’t enlisted for the military service and started his job at NIG-1 one year earlier. Sergey has good brains and interest to what he is doing. The interest led him to programming in M-20 machine codes, and, after some exercises, he started to realize new ideas for the PRASAK development.

The first idea was implementation of the Fully Stressed Design (FSD) algorithm. This is important tool for structural optimization at early design stages. Sergey programmed the simple recurrence relation for membrane element thicknesses and rod cross section areas. The program worked successfully and was used for so called theoretically optimal material distribution search. Some researches are still playing with similar programs calling them topological optimizer. And this was and still is practical approach. Fully stressed algorithm deletes materials from the zones where it is not loaded and adds material in places where stresses are higher than allowables. Such fully stressed design gives good hints for designer how the structural scheme can look like. And even more important for designer is the knowledge about internal forces distribution in the FSD. Internal forces are the base for real detailed design. This technique was used effectively for structural design of the fuselage main frames for blended wing-body schemes in particular.

The second idea was programming for plotter. It’s so difficult now even to imaging how we managed to debug finite element model without visualization. Yes, it was not simple. But we had no not only monitor screens, but plotters too. Therefore, to see what our model is we made visualization by hands using squared paper. All this changed when KuAI obtained the first plotter, named Vector. Vector was one pen two axis plotter with simple command system. There was only one computer, BESM-4 to which we could connect it. However there was no software even in M-20 codes for the Vector in our possession. Somebody told us that programmers in Novosibirsk University wrote this software for Vector attached to BESM-4. In January 1977 I was sent for business trip to Novosibisk Academ Gorodok (Campus of the Siberia Branch of the Russian Academy of Sciences) with the order to make copy of their software. I made two copies and brought them back. The software realizes the basic plotter command like “lift the pen”, “drop the pen”, “make horizontal incremental step”, “make vertical incremental step”. These four commands were enough for Sergey to write a program which made our work much more effective.

Six year anniversary and Stressmen 7

Six years ago we landed here:

Six years are a children age and we still continue to wonder the beauty of the Beautiful British Columbia.

Walking on the beach I was thinking about continuation of my story. Stressmen 7

The NIG-1 had a bicipital leadership in the faces of Katya Ivanova and her husband, Volodya Peresypkin. Katya was a good manager and Volodya provided engineering supervision. The first successful algorithms and programming of the finite element method was done by Volodya. PRASAK is the name of the software written in M-20 machine codes and working at such computers like BESM-4, M-220 and M-222. As usually the first version of the PRASAK had lots of bugs and Ghenya Makeev was a person who debugged it effectively, tested, made some modifications and shaped finally into commercial version, which could be distributed. The PRASAK’s finite element library contained several elements: rod, triangle, shear panel, membrane panel and I-beam. Four triangles were used for panel creation. Internal node was eliminated during triangles combining. I-beam element was a combination of web (membrane panel) and two caps (rods). In the early 70-s, knowing nothing about “shear locking”, Peresypkin and Makeev resolved problem of excessive shear stiffness by redistribution material between web triangles. Beam’s caps had eccentricities and element was very effective for simulation of the spars, ribs and frames.

There were several part-time researchers in the NIG-1. One of them, Alexander Solovov, created effective tool for the wing topological optimization in the PRASAK’s package. The tool allowed defining of the number and position of spars and ribs, their orientations and mass properties together with mass properties of the skins. Special eight node ”sandwich” element was a base of this tool. The “sandwich” consisted of two membrane skins and pure shear core between them. Such elements were used for wing structure simulation at the earliest design stages. Several critical load cases have to be applied. Structural mass was minimized and von Mises stresses in the skins and shear stresses in the core were constrained by their allowable values. Fully stressed design algorithm was applied to the model. The convergence was reached fast due to the fact that such structure behaves like statically determined. Main internal loads distribution in the skins and core were used as major output. Their analysis gave a good idea about spar positioning, their orientation, rib’s pitch and orientation. So called “theoretical weight” was defined by this model too. This is a weight of such fully stressed sandwich model. “Theoretical weight” is a good criterion for different structural schemes comparison at early design stages.

Wild beaches and Stressmen 6

Clothing is optional on the beaches like this:

And only the signs like this ask you to put something on:

Summer is still here, but the days are shorter and some kind of the fall spirit is in the air:

There are many other fall tokens. For example, this boat at Lulu mooring:

The Tartu wears Canadian flag, not Estonian. And this is right, because Tartu is an inlet on the Queen Charlotte Island, not the university city on the Baltic you’ve thought. Guys brought wild salmon and other sea products for sale.

And I continue my story. Stressmen 6

My first task was graphical presentation of analysis results obtained for A-50 (Soviet AWACS) antenna fairing. A-50 was Beriev’s modification of the Il-76 into airborne early warning plane. It was designed and manufactured at TASTC (Taganrog Aviation Scientific-Technical Complex). NIG-1 has strong and reliable links with this company for many years.

Fiberglass fairing had a complicated sandwich structure: upper face skin, upper honeycomb core, internal skin, lower core, and back face skin. Usage of two cores gave a chance to reduce honeycomb cell height and, as a result of this, increase stresses of honeycomb local buckling. Antenna was fixed on the central thin-wall box which provided its rotation and was attached to the antenna pylon.

KPRK (Komplex Prochnastnogo Raschetf Kryliev or Wing Stress Analysis Complex) created by Victor Glezer at Tupolev Design Bureau was used as a major analysis tool. KPRK was a simple and one of the first finite element software for the Soviet BESM-4 computer. There were only two types of element: two node rod and for node pure shear panel. But this software was revolution in thin wall structures analysis and even two simple elements were good enough for accurate simulation of redundant structures and their effective analysis.

My task was simple and boring. There were not only screens not available for graphic output, but even plotters were not in our possession yet. What we had as analysis results output were listings, long paper tapes with numbers printed in columns. Finite element mesh templates were used for manual data presentation in graphical format. First we manually wrote stress numbers for every particular element for every particular load case and then, if needed, provided this data interpolation into graphs. The fairing cross section shape resembled cucumber and we called this task “penciling cucumbers”.

The major goal was to find the answer to the following question. Which type of fiberglass fairing fixing on the metal central box has to be applied: cantilevered of pivoted? And we proved that pivoted is much better from structural behavior with much less reactions at fairing-box connection.

Working on the “cucumbers” was not the only thing I had for office time spending. I started self education in the finite element analysis area. O.K. Zenkevich “Finite Element Method in Engineering” book was on of the first but not the best. The bad Xerox copy of “Theory of Matrix Structural Analysis” of J.S. Przemieniecki was revealed soon. And of course meeting with NIG-1 personnel, making acquaintance, conversations, discussions were the most important subject of this introductory period of my new job.

Garibaldi Lake and Stressmen 5

It took me 3 hours to hike this place (9 km with 900 m elevation):

The swimming was refreshing. And, of course, I was thinking about my story a little. Stressmen 5

At 10 am on the 3d of April 1976 I was staying near the KiPLA chair door on the second floor of the third KuAI’s building. I had an appointment for introductory meeting with my new boss, Scientific Supervisor of the NIG-1 (NIG is Nauchno Issledovatelskaya Gruppa or Scientific Research Group), Docent Valery Andreevich Komarov. The chair secretary told me that Valery Andreevich is reading lecture now and will be here soon. One more person, the student like looking guy, was waiting Docent Komarov too. I started simple conversation and made my introduction telling him my name and the reason of my presence here. Vitaly Mateveev, the student of the fifth course, was serious, not willing for chatting but answered my questions.

“Are you working for Komarov?” – was my first question.

“Yes” – Vitaly was short.

“And what kind of work are you doing for him?”

“We are developing special analysis tools, finite elements in particular”

“For what kind of the airplane?” – I continued.

“For the Il-86” – was the short answer again.

It was a positive surprise for me, because my suggestions to what can be done in the KuAI for structural design were not going further than Serial Design Bureau of the Kuibyshev Aviation Plant.

Valery Andreevich arrived at 10:10 and after short conversation with Vitaly on the subject of his future diploma project he took me to the NIG-1.

I was introduced to Ekaterina Alexeevna Ivanova, manager, and the NIG-1 leads in the room #101. Ekaterina Alexeevna told me that I will be working under supervision of Valery Mischuk and we moved to the room on the opposite side of the corridor then. Valery showed me my desk and my first working day as a junior researcher started.

Nice September weather, bird-cherries and Stressmen 4

It was not a bad idea to check if we have mushrooms of this season above the ground after couple of real rains. I had a good walk in the forest and made conclusion that mushrooms are still sitting in the soil. But I found something even more interesting:

The name of these berries is cheryomukha or bird-cherries. They are very tasty with smell and flavor of my childhood. The car was parked not far from this beach::

Nice place to sit a little and think about the events happened many years ago. Stressmen 4

I served as a lieutenant and a senior lieutenant of strategic missile regiment in the Soviet Army. It was compulsory service and I was conscripted to it simultaneously with my graduation from SSAU. My Missilemen story in ten portions is published in the blog and you can see the links in the right column of this page.

At the end of the second year there was serious proposal to continue the service as a regular officer with many benefits like salary two times higher in comparison with an engineer, good accommodation and social package. But I was not ready for this and understand well that money is not everything in this world. My sole belonged to Volga, Ghiguly, sailing, diving, hiking and good time spending with my friends in Samara. I couldn’t image my life without this. There were many possibilities to be employed in Samara, because it was one of the biggest aerospace centers of the Soviet Union. It was guarantied place for me in such companies like Kuibyshev Aviation Plant where the Tu-154 and the Tu-95 were manufacturing or Progress Plant with South launcher production. But I didn’t even think about possibility to work at military production oriented factory with its very strict regulations. I remembered well the word of my uncle Vitya, who spent all his life in Progress’s shops:

“Slava, enjoy your student’s life now. After graduation you will go to military plant and spend your life surrounded by barbed wires and armed securities. Believe me, the plant is the same what the labor camp is”.

Of course I didn’t dream about labor camp and linked my future with the job which is interesting for me and gives me time for other kind of activities. There were not many places like this and one of them was a position of junior researcher in my alma mater. It was very attractive for me, because every year summer vacation was guarantied by this position. I started to think about this in February 1976 and wrote a letter to aircraft design department with description of my desire. I mentioned that I graduated with excellent marks of my diploma project and all aerospace disciplines we were taught. Of course I remembered about my research work and results I got in sandwich panel optimization. The reply arrived in March. It was written by Valery Komarov who told me that I can start my work in KiPLA chair as junior researcher in April.

I knew nothing what are they doing in KiPLA related to research but believed that this is the best alternative I have. It seems to me now that this was right decision.